Maven系列第8篇：大型Maven项目，快速按需任意构建

azhou的代码园2023-10-21 12:02

本篇涉及到的内容属于神技能，多数使用maven的人都经常想要的一种功能，但是大多数人都不知道如何使用，废话不多说，上干货。

需求背景

我们需要做一个电商项目，一般都会做成微服务的形式，按业务进行划分，本次我们主要以账户业务 和订单业务为例，我们将这两块业务分别作为2个大的模块来开发，而订单模块又会调用账户模块中的接口，所以对账户模块接口部分会有依赖。

我们以maven来搭建项目，项目的目录结构如下：

b2b
    b2b-account
        b2b-account-api
        b2b-account-service
    b2b-order
        b2b-order-api
        b2b-order-service
b2b-account

账户模块，其中包含2个小模块：b2b-account-api和b2b-account-service

b2b-account-api

账户模块对外暴露的接口部分，以供外部调用

b2b-account-service

账户模块具体业务实现，依赖于b2b-account-api模块

b2b-order

订单模块，也是包含2个小模块：b2b-order-api和b2b-order-service

b2b-order-api

订单模块对外暴露的接口部分，以供外部调用

b2b-order-service

订单模块具体业务实现，依赖2个模块b2b-order-api、b2b-account-api

搭建项目结构

我们按照上面的需求，使用maven搭建项目结构，具体过程如下。

创建b2b项目

打开idea，点击File->New->Project，如下图：

选择Maven，如下图：

点击上图的Next，输入坐标信息，如下图：

点击上图的Next，输入Project Name为b2b，如下图：

点击上图的Finish，完成项目的创建，如下图：

删除下图中无用的代码：

变成了下面这样：

配置一下idea的maven环境，点击File->Settings，如下图：

点击上面的OK完成配置。

在b2b下创建b2b-account模块

注意这里是创建模块，不是项目了，注意下面的操作过程。

选中b2b项目目录，如下图：

点击File->New->Module，如下图：

选择Maven，如下图：

点击Next，如下图：

点击上面第二个...，将Parent置为None，如下图：

输入坐标信息，如下图：

点击上图中的Next，输入Project name为b2b-account，如下图：

点击Finish，完成b2b-account模块的创建，如下图：

删除b2b-account中src目录，如下图：

项目结构变成了下面这样：

在b2b-account模块下面创建b2b-account-api模块

选中b2b-account，如下图：

点击File->New->Module，如下图：

选择Maven，如下图：

点击上图中的Next，如下图：

将上面的Add as module to设置为b2b-account模块，表示新增的这个模块被b2b-account聚合进行管理。

点击Parent后面的...，选择None，将Parent对应的值置为None。

如下图：

输入坐标信息，如下图：

点击Next，默认如下图：

我们需要对上面3个输入框的值进行修改，修改成下面这样：

点击Finish，完成创建，如下图：

在b2b-account模块下创建b2b-account-service模块

这个过程参考在b2b-account模块下面创建b2b-account-api模块。

在b2b下创建b2b-order模块

这个过程参考在b2b下创建b2b-account模块。

在b2b-order模块下面创建b2b-order-api模块

这个过程参考在b2b-account模块下面创建b2b-account-api模块。

在b2b-order模块下面创建b2b-order-service模块

这个过程参考在b2b-account模块下面创建b2b-account-api模块。

项目结构创建成功

上面都创建成功之后，项目结构如下图

参与过大型maven项目开发的是不是很熟悉很亲切，多数互联网项目的maven结构就是这样一大片maven模块。

引入项目依赖

b2b-account-service依赖于b2b-account-api模块，所以在b2b-account-service/pom.xml中加入下面配置：

<dependencies>
    <dependency>
        <groupId>${project.groupId}</groupId>
        <artifactId>b2b-account-api</artifactId>
        <version>${project.version}</version>
    </dependency>
</dependencies>

由于项目的groupId,version都是一样的，所以直接通过${}这种方式引用了。

b2b-order-service依赖2个模块b2b-order-api、b2b-account-api，所以在b2b-order-service/pom.xml中加入下面配置：

<dependencies>
    <dependency>
        <groupId>${project.groupId}</groupId>
        <artifactId>b2b-account-api</artifactId>
        <version>${project.version}</version>
    </dependency>
    <dependency>
        <groupId>${project.groupId}</groupId>
        <artifactId>b2b-order-api</artifactId>
        <version>${project.version}</version>
    </dependency>
</dependencies>
此时每个模块pom.xml如下
b2b/pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.javacode2018</groupId>
    <artifactId>b2b</artifactId>
    <packaging>pom</packaging>
    <version>1.0-SNAPSHOT</version>
    <modules>
        <module>b2b-account</module>
        <module>b2b-order</module>
    </modules>

</project>
b2b-account/pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.javacode2018</groupId>
    <artifactId>b2b-account</artifactId>
    <packaging>pom</packaging>
    <version>1.0-SNAPSHOT</version>
    <modules>
        <module>b2b-account-api</module>
        <module>b2b-account-service</module>
    </modules>

</project>
b2b-account-api/pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.javacode2018</groupId>
    <artifactId>b2b-account-api</artifactId>
    <version>1.0-SNAPSHOT</version>

</project>
b2b-account-service/pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.javacode2018</groupId>
    <artifactId>b2b-account-service</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>${project.groupId}</groupId>
            <artifactId>b2b-account-api</artifactId>
            <version>${project.version}</version>
        </dependency>
    </dependencies>

</project>
b2b-order/pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.javacode2018</groupId>
    <artifactId>b2b-order</artifactId>
    <packaging>pom</packaging>
    <version>1.0-SNAPSHOT</version>
    <modules>
        <module>b2b-order-api</module>
        <module>b2b-order-service</module>
    </modules>

</project>
b2b-order-api/pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.javacode2018</groupId>
    <artifactId>b2b-order-api</artifactId>
    <version>1.0-SNAPSHOT</version>

</project>
b2b-order-service/pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.javacode2018</groupId>
    <artifactId>b2b-order-service</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>${project.groupId}</groupId>
            <artifactId>b2b-account-api</artifactId>
            <version>${project.version}</version>
        </dependency>
        <dependency>
            <groupId>${project.groupId}</groupId>
            <artifactId>b2b-order-api</artifactId>
            <version>${project.version}</version>
        </dependency>
    </dependencies>

</project>

注意：上面项目的结构属于父子结构，使用maven中聚合的方式进行管理的，对应聚合不是太了解的，可以看上篇文章有详细介绍。

b2b中包含了2个子模块b2b_account和b2b_order，这3个package都是pom。

b2b_account中包含了2个子模块，2个子模块package是默认的jar类型。

b2b_order中包含了2个子模块，2个子模块package是默认的jar类型。

反应堆

上面项目都开发好了，我们需要安装到本地仓库，一般情况下，我们会这么做，在b2b/pom.xml所在目录执行下面命令：

mvn clean install

我们来感受一下这个命令的效果：

D:\code\IdeaProjects\b2b>mvn clean install
[INFO] Scanning for projects...
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Build Order:
[INFO]
[INFO] b2b-account-api                                                    [jar]
[INFO] b2b-account-service                                                [jar]
[INFO] b2b-account                                                        [pom]
[INFO] b2b-order-api                                                      [jar]
[INFO] b2b-order-service                                                  [jar]
[INFO] b2b-order                                                          [pom]
[INFO] b2b                                                                [pom]
[INFO]
[INFO] ------------------< com.javacode2018:b2b-account-api >------------------
[INFO] Building b2b-account-api 1.0-SNAPSHOT                              [1/7]
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ b2b-account-api ---
[INFO] Deleting D:\code\IdeaProjects\b2b\b2b-account\b2b-account-api\target
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ b2b-account-api ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] Copying 0 resource
[INFO]
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ b2b-account-api ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ b2b-account-api ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory D:\code\IdeaProjects\b2b\b2b-account\b2b-account-api\src\test\resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ b2b-account-api ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ b2b-account-api ---
[INFO] No tests to run.
[INFO]
[INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ b2b-account-api ---
[INFO] Building jar: D:\code\IdeaProjects\b2b\b2b-account\b2b-account-api\target\b2b-account-api-1.0-SNAPSHOT.jar
[INFO]
[INFO] --- maven-install-plugin:2.4:install (default-install) @ b2b-account-api ---
[INFO] Installing D:\code\IdeaProjects\b2b\b2b-account\b2b-account-api\target\b2b-account-api-1.0-SNAPSHOT.jar to C:\Users\Think\.m2\repository\com\javacode2018\b2b-account-api\1.0-SNAPSHOT\b2b-account-api-1.0-SNAPSHOT.jar
[INFO] Installing D:\code\IdeaProjects\b2b\b2b-account\b2b-account-api\pom.xml to C:\Users\Think\.m2\repository\com\javacode2018\b2b-account-api\1.0-SNAPSHOT\b2b-account-api-1.0-SNAPSHOT.pom
[INFO]
[INFO] ----------------< com.javacode2018:b2b-account-service >----------------
[INFO] Building b2b-account-service 1.0-SNAPSHOT                          [2/7]
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ b2b-account-service ---
[INFO] Deleting D:\code\IdeaProjects\b2b\b2b-account\b2b-account-service\target
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ b2b-account-service ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] Copying 0 resource
[INFO]
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ b2b-account-service ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ b2b-account-service ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory D:\code\IdeaProjects\b2b\b2b-account\b2b-account-service\src\test\resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ b2b-account-service ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ b2b-account-service ---
[INFO] No tests to run.
[INFO]
[INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ b2b-account-service ---
[INFO] Building jar: D:\code\IdeaProjects\b2b\b2b-account\b2b-account-service\target\b2b-account-service-1.0-SNAPSHOT.jar
[INFO]
[INFO] --- maven-install-plugin:2.4:install (default-install) @ b2b-account-service ---
[INFO] Installing D:\code\IdeaProjects\b2b\b2b-account\b2b-account-service\target\b2b-account-service-1.0-SNAPSHOT.jar to C:\Users\Think\.m2\repository\com\javacode2018\b2b-account-service\1.0-SNAPSHOT\b2b-account-service-1.0-SNAPSHOT.jar
[INFO] Installing D:\code\IdeaProjects\b2b\b2b-account\b2b-account-service\pom.xml to C:\Users\Think\.m2\repository\com\javacode2018\b2b-account-service\1.0-SNAPSHOT\b2b-account-service-1.0-SNAPSHOT.pom
[INFO]
[INFO] --------------------< com.javacode2018:b2b-account >--------------------
[INFO] Building b2b-account 1.0-SNAPSHOT                                  [3/7]
[INFO] --------------------------------[ pom ]---------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ b2b-account ---
[INFO]
[INFO] --- maven-install-plugin:2.4:install (default-install) @ b2b-account ---
[INFO] Installing D:\code\IdeaProjects\b2b\b2b-account\pom.xml to C:\Users\Think\.m2\repository\com\javacode2018\b2b-account\1.0-SNAPSHOT\b2b-account-1.0-SNAPSHOT.pom
[INFO]
[INFO] -------------------< com.javacode2018:b2b-order-api >-------------------
[INFO] Building b2b-order-api 1.0-SNAPSHOT                                [4/7]
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ b2b-order-api ---
[INFO] Deleting D:\code\IdeaProjects\b2b\b2b-order\b2b-order-api\target
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ b2b-order-api ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] Copying 0 resource
[INFO]
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ b2b-order-api ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ b2b-order-api ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory D:\code\IdeaProjects\b2b\b2b-order\b2b-order-api\src\test\resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ b2b-order-api ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ b2b-order-api ---
[INFO] No tests to run.
[INFO]
[INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ b2b-order-api ---
[INFO] Building jar: D:\code\IdeaProjects\b2b\b2b-order\b2b-order-api\target\b2b-order-api-1.0-SNAPSHOT.jar
[INFO]
[INFO] --- maven-install-plugin:2.4:install (default-install) @ b2b-order-api ---
[INFO] Installing D:\code\IdeaProjects\b2b\b2b-order\b2b-order-api\target\b2b-order-api-1.0-SNAPSHOT.jar to C:\Users\Think\.m2\repository\com\javacode2018\b2b-order-api\1.0-SNAPSHOT\b2b-order-api-1.0-SNAPSHOT.jar
[INFO] Installing D:\code\IdeaProjects\b2b\b2b-order\b2b-order-api\pom.xml to C:\Users\Think\.m2\repository\com\javacode2018\b2b-order-api\1.0-SNAPSHOT\b2b-order-api-1.0-SNAPSHOT.pom
[INFO]
[INFO] -----------------< com.javacode2018:b2b-order-service >-----------------
[INFO] Building b2b-order-service 1.0-SNAPSHOT                            [5/7]
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ b2b-order-service ---
[INFO] Deleting D:\code\IdeaProjects\b2b\b2b-order\b2b-order-service\target
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ b2b-order-service ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] Copying 0 resource
[INFO]
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ b2b-order-service ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ b2b-order-service ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory D:\code\IdeaProjects\b2b\b2b-order\b2b-order-service\src\test\resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ b2b-order-service ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ b2b-order-service ---
[INFO] No tests to run.
[INFO]
[INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ b2b-order-service ---
[INFO] Building jar: D:\code\IdeaProjects\b2b\b2b-order\b2b-order-service\target\b2b-order-service-1.0-SNAPSHOT.jar
[INFO]
[INFO] --- maven-install-plugin:2.4:install (default-install) @ b2b-order-service ---
[INFO] Installing D:\code\IdeaProjects\b2b\b2b-order\b2b-order-service\target\b2b-order-service-1.0-SNAPSHOT.jar to C:\Users\Think\.m2\repository\com\javacode2018\b2b-order-service\1.0-SNAPSHOT\b2b-order-service-1.0-SNAPSHOT.jar
[INFO] Installing D:\code\IdeaProjects\b2b\b2b-order\b2b-order-service\pom.xml to C:\Users\Think\.m2\repository\com\javacode2018\b2b-order-service\1.0-SNAPSHOT\b2b-order-service-1.0-SNAPSHOT.pom
[INFO]
[INFO] ---------------------< com.javacode2018:b2b-order >---------------------
[INFO] Building b2b-order 1.0-SNAPSHOT                                    [6/7]
[INFO] --------------------------------[ pom ]---------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ b2b-order ---
[INFO]
[INFO] --- maven-install-plugin:2.4:install (default-install) @ b2b-order ---
[INFO] Installing D:\code\IdeaProjects\b2b\b2b-order\pom.xml to C:\Users\Think\.m2\repository\com\javacode2018\b2b-order\1.0-SNAPSHOT\b2b-order-1.0-SNAPSHOT.pom
[INFO]
[INFO] ------------------------< com.javacode2018:b2b >------------------------
[INFO] Building b2b 1.0-SNAPSHOT                                          [7/7]
[INFO] --------------------------------[ pom ]---------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ b2b ---
[INFO]
[INFO] --- maven-install-plugin:2.4:install (default-install) @ b2b ---
[INFO] Installing D:\code\IdeaProjects\b2b\pom.xml to C:\Users\Think\.m2\repository\com\javacode2018\b2b\1.0-SNAPSHOT\b2b-1.0-SNAPSHOT.pom
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary for b2b 1.0-SNAPSHOT:
[INFO]
[INFO] b2b-account-api .................................... SUCCESS [  1.806 s]
[INFO] b2b-account-service ................................ SUCCESS [  0.298 s]
[INFO] b2b-account ........................................ SUCCESS [  0.082 s]
[INFO] b2b-order-api ...................................... SUCCESS [  0.229 s]
[INFO] b2b-order-service .................................. SUCCESS [  0.254 s]
[INFO] b2b-order .......................................... SUCCESS [  0.058 s]
[INFO] b2b ................................................ SUCCESS [  0.069 s]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  3.072 s
[INFO] Finished at: 2019-11-20T16:03:27+08:00
[INFO] ------------------------------------------------------------------------

注意上面有这样的输出：

[INFO] Reactor Build Order:
[INFO]
[INFO] b2b-account-api                                                    [jar]
[INFO] b2b-account-service                                                [jar]
[INFO] b2b-account                                                        [pom]
[INFO] b2b-order-api                                                      [jar]
[INFO] b2b-order-service                                                  [jar]
[INFO] b2b-order                                                          [pom]
[INFO] b2b                                                                [pom]

maven会根据模块之间的依赖关系，然后会得到所有模块的构建顺序，上面共有7个pom.xml文件，也就是7个maven构件，按照上面列出的顺序依次进行构建。

可以看到b2b-account-api是被其他一些模块依赖的，所以这个放在了第一个。

mvn命令对多模块构件时，会根据模块的依赖关系而得到模块的构建顺序，这个功能就是maven的反应堆（reactor）做的事情，反应堆会根据模块之间的依赖关系、聚合关系、继承关系等等，从而计算得出一个合理的模块构建顺序，所以反应堆的功能是相当强大的。

按需随意构建

有这样的一种场景：b2b-account-api被b2b-account-service和b2b-order-service依赖了，所以当b2b-account-api有修改的时候，我们希望他们3个都能够被重新构建一次，而不是去对所有的模块都进行重新构建，我们只希望被影响的模块都能够参与重新构建，大家有什么好的办法？

上面列出的只是2个模块的功能，真正的电商项目还有很多模块，如果每次修改一个模块，我们都去重新打包所有的模块，这个构建过程耗时是非常久的，只能干等着，我们需要的是按需构建，需要构建哪些模块让我们自己能够随意指定，这样也可以加快构建的速度，所以我们需要这样的功能

maven反应堆帮我们考虑到了这种情况，mvn命令提供了一些功能可以帮我们实现这些操作，我们看一下mvn的帮助文档，mvn -h可以查看帮助，如下：

D:\code\IdeaProjects\b2b>mvn -h

usage: mvn [options] [<goal(s)>] [<phase(s)>]

Options:
 -am,--also-make                        If project list is specified, also
                                        build projects required by the
                                        list
 -amd,--also-make-dependents            If project list is specified, also
                                        build projects that depend on
                                        projects on the list
 -B,--batch-mode                        Run in non-interactive (batch)
                                        mode (disables output color)
 -b,--builder <arg>                     The id of the build strategy to
                                        use
 -C,--strict-checksums                  Fail the build if checksums don't
                                        match
 -c,--lax-checksums                     Warn if checksums don't match
 -cpu,--check-plugin-updates            Ineffective, only kept for
                                        backward compatibility
 -D,--define <arg>                      Define a system property
 -e,--errors                            Produce execution error messages
 -emp,--encrypt-master-password <arg>   Encrypt master security password
 -ep,--encrypt-password <arg>           Encrypt server password
 -f,--file <arg>                        Force the use of an alternate POM
                                        file (or directory with pom.xml)
 -fae,--fail-at-end                     Only fail the build afterwards;
                                        allow all non-impacted builds to
                                        continue
 -ff,--fail-fast                        Stop at first failure in
                                        reactorized builds
 -fn,--fail-never                       NEVER fail the build, regardless
                                        of project result
 -gs,--global-settings <arg>            Alternate path for the global
                                        settings file
 -gt,--global-toolchains <arg>          Alternate path for the global
                                        toolchains file
 -h,--help                              Display help information
 -l,--log-file <arg>                    Log file where all build output
                                        will go (disables output color)
 -llr,--legacy-local-repository         Use Maven 2 Legacy Local
                                        Repository behaviour, ie no use of
                                        _remote.repositories. Can also be
                                        activated by using
                                        -Dmaven.legacyLocalRepo=true
 -N,--non-recursive                     Do not recurse into sub-projects
 -npr,--no-plugin-registry              Ineffective, only kept for
                                        backward compatibility
 -npu,--no-plugin-updates               Ineffective, only kept for
                                        backward compatibility
 -nsu,--no-snapshot-updates             Suppress SNAPSHOT updates
 -ntp,--no-transfer-progress            Do not display transfer progress
                                        when downloading or uploading
 -o,--offline                           Work offline
 -P,--activate-profiles <arg>           Comma-delimited list of profiles
                                        to activate
 -pl,--projects <arg>                   Comma-delimited list of specified
                                        reactor projects to build instead
                                        of all projects. A project can be
                                        specified by [groupId]:artifactId
                                        or by its relative path
 -q,--quiet                             Quiet output - only show errors
 -rf,--resume-from <arg>                Resume reactor from specified
                                        project
 -s,--settings <arg>                    Alternate path for the user
                                        settings file
 -t,--toolchains <arg>                  Alternate path for the user
                                        toolchains file
 -T,--threads <arg>                     Thread count, for instance 2.0C
                                        where C is core multiplied
 -U,--update-snapshots                  Forces a check for missing
                                        releases and updated snapshots on
                                        remote repositories
 -up,--update-plugins                   Ineffective, only kept for
                                        backward compatibility
 -v,--version                           Display version information
 -V,--show-version                      Display version information
                                        WITHOUT stopping build
 -X,--debug                             Produce execution debug output

上面列出了mvn命令后面的一些选项，有几个选项本次我们需要用到，如下：

-pl,--projects <arg>

构件指定的模块，arg表示多个模块，之间用逗号分开，模块有两种写法

-pl 模块1相对路径 [,模块2相对路径] [,模块n相对路径]
-pl [模块1的groupId]:模块1的artifactId [,[模块2的groupId]:模块2的artifactId] [,[模块n的groupId]:模块n的artifactId]

举例：

下面命令都是在b2b/pom.xml来运行

mvn clean install -pl b2b-account
mvn clean install -pl b2b-account/b2b-account-api
mvn clean install -pl b2b-account/b2b-account-api,b2b-account/b2b-account-service
mvn clean install -pl :b2b-account-api,b2b-order/b2b-order-api
mvn clean install -pl :b2b-account-api,:b2b-order-service
-rf,--resume-from <arg>

从指定的模块恢复反应堆

-am,--also-make

同时构建所列模块的依赖模块

-amd,--also-make-dependents

同时构件依赖于所列模块的模块

下面我们通过6个案例细说上面这些用法。

注意：下面所有案例都在b2b/pom.xml所在目录执行。

案例1

只构建p-account模块，运行命令

mvn clean install -pl b2b-account

效果如下：

D:\code\IdeaProjects\b2b>mvn clean install -pl b2b-account
[INFO] Scanning for projects...
[INFO]
[INFO] --------------------< com.javacode2018:b2b-account >--------------------
[INFO] Building b2b-account 1.0-SNAPSHOT
[INFO] --------------------------------[ pom ]---------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ b2b-account ---
[INFO]
[INFO] --- maven-install-plugin:2.4:install (default-install) @ b2b-account ---
[INFO] Installing D:\code\IdeaProjects\b2b\b2b-account\pom.xml to C:\Users\Think\.m2\repository\com\javacode2018\b2b-account\1.0-SNAPSHOT\b2b-account-1.0-SNAPSHOT.pom
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  0.907 s
[INFO] Finished at: 2019-11-20T16:12:51+08:00
[INFO] ------------------------------------------------------------------------

可以看到只构建了b2b-account。

案例2

只构建b2b-account-api模块，运行命令：

mvn clean install -pl b2b-account/b2b-account-api

效果如下：

D:\code\IdeaProjects\b2b>mvn clean install -pl b2b-account/b2b-account-api
[INFO] Scanning for projects...
[INFO]
[INFO] ------------------< com.javacode2018:b2b-account-api >------------------
[INFO] Building b2b-account-api 1.0-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ b2b-account-api ---
[INFO] Deleting D:\code\IdeaProjects\b2b\b2b-account\b2b-account-api\target
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ b2b-account-api ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] Copying 0 resource
[INFO]
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ b2b-account-api ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ b2b-account-api ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory D:\code\IdeaProjects\b2b\b2b-account\b2b-account-api\src\test\resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ b2b-account-api ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ b2b-account-api ---
[INFO] No tests to run.
[INFO]
[INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ b2b-account-api ---
[INFO] Building jar: D:\code\IdeaProjects\b2b\b2b-account\b2b-account-api\target\b2b-account-api-1.0-SNAPSHOT.jar
[INFO]
[INFO] --- maven-install-plugin:2.4:install (default-install) @ b2b-account-api ---
[INFO] Installing D:\code\IdeaProjects\b2b\b2b-account\b2b-account-api\target\b2b-account-api-1.0-SNAPSHOT.jar to C:\Users\Think\.m2\repository\com\javacode2018\b2b-account-api\1.0-SNAPSHOT\b2b-account-api-1.0-SNAPSHOT.jar
[INFO] Installing D:\code\IdeaProjects\b2b\b2b-account\b2b-account-api\pom.xml to C:\Users\Think\.m2\repository\com\javacode2018\b2b-account-api\1.0-SNAPSHOT\b2b-account-api-1.0-SNAPSHOT.pom
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  2.853 s
[INFO] Finished at: 2019-11-20T16:14:37+08:00
[INFO] ------------------------------------------------------------------------

上面使用的是相对路径的写法，还有2种写法，大家可以去试试，如下：

mvn clean install -pl :b2b-account-api
mvn clean install -pl com.javacode2018:b2b-account-api

案例3

构建b2b-account-api和b2b-order-api，运行下面命令：

mvn clean install -pl b2b-account/b2b-account-api,b2b-order/b2b-order-api

效果如下：

D:\code\IdeaProjects\b2b>mvn clean install -pl b2b-account/b2b-account-api,b2b-order/b2b-order-api
[INFO] Scanning for projects...
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Build Order:
[INFO]
[INFO] b2b-account-api                                                    [jar]
[INFO] b2b-order-api                                                      [jar]
[INFO]
[INFO] ------------------< com.javacode2018:b2b-account-api >------------------
[INFO] Building b2b-account-api 1.0-SNAPSHOT                              [1/2]
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ b2b-account-api ---
[INFO] Deleting D:\code\IdeaProjects\b2b\b2b-account\b2b-account-api\target
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ b2b-account-api ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] Copying 0 resource
[INFO]
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ b2b-account-api ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ b2b-account-api ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory D:\code\IdeaProjects\b2b\b2b-account\b2b-account-api\src\test\resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ b2b-account-api ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ b2b-account-api ---
[INFO] No tests to run.
[INFO]
[INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ b2b-account-api ---
[INFO] Building jar: D:\code\IdeaProjects\b2b\b2b-account\b2b-account-api\target\b2b-account-api-1.0-SNAPSHOT.jar
[INFO]
[INFO] --- maven-install-plugin:2.4:install (default-install) @ b2b-account-api ---
[INFO] Installing D:\code\IdeaProjects\b2b\b2b-account\b2b-account-api\target\b2b-account-api-1.0-SNAPSHOT.jar to C:\Users\Think\.m2\repository\com\javacode2018\b2b-account-api\1.0-SNAPSHOT\b2b-account-api-1.0-SNAPSHOT.jar
[INFO] Installing D:\code\IdeaProjects\b2b\b2b-account\b2b-account-api\pom.xml to C:\Users\Think\.m2\repository\com\javacode2018\b2b-account-api\1.0-SNAPSHOT\b2b-account-api-1.0-SNAPSHOT.pom
[INFO]
[INFO] -------------------< com.javacode2018:b2b-order-api >-------------------
[INFO] Building b2b-order-api 1.0-SNAPSHOT                                [2/2]
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ b2b-order-api ---
[INFO] Deleting D:\code\IdeaProjects\b2b\b2b-order\b2b-order-api\target
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ b2b-order-api ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] Copying 0 resource
[INFO]
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ b2b-order-api ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ b2b-order-api ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory D:\code\IdeaProjects\b2b\b2b-order\b2b-order-api\src\test\resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ b2b-order-api ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ b2b-order-api ---
[INFO] No tests to run.
[INFO]
[INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ b2b-order-api ---
[INFO] Building jar: D:\code\IdeaProjects\b2b\b2b-order\b2b-order-api\target\b2b-order-api-1.0-SNAPSHOT.jar
[INFO]
[INFO] --- maven-install-plugin:2.4:install (default-install) @ b2b-order-api ---
[INFO] Installing D:\code\IdeaProjects\b2b\b2b-order\b2b-order-api\target\b2b-order-api-1.0-SNAPSHOT.jar to C:\Users\Think\.m2\repository\com\javacode2018\b2b-order-api\1.0-SNAPSHOT\b2b-order-api-1.0-SNAPSHOT.jar
[INFO] Installing D:\code\IdeaProjects\b2b\b2b-order\b2b-order-api\pom.xml to C:\Users\Think\.m2\repository\com\javacode2018\b2b-order-api\1.0-SNAPSHOT\b2b-order-api-1.0-SNAPSHOT.pom
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary for b2b-account-api 1.0-SNAPSHOT:
[INFO]
[INFO] b2b-account-api .................................... SUCCESS [  2.874 s]
[INFO] b2b-order-api ...................................... SUCCESS [  0.393 s]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  3.554 s
[INFO] Finished at: 2019-11-20T16:15:57+08:00
[INFO] ------------------------------------------------------------------------

上面输出中可以看到只构建了2个目标模块。

案例4

我们只修改了b2b-account-api代码，所以我希望对这个重新打包，并且对这个有依赖的也重新打包，所以需要打包下面3个模块：

b2b-account-api
b2b-account-service
b2b-order-service

上面列表中的后面两个是依赖于b2b-account-api的，可以在b2b/pom.xml中执行下面命令：

mvn clean install -pl b2b-account/b2b-account-api -amd

我们看一下效果：

D:\code\IdeaProjects\b2b>mvn clean install -pl b2b-account/b2b-account-api -amd
[INFO] Scanning for projects...
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Build Order:
[INFO]
[INFO] b2b-account-api                                                    [jar]
[INFO] b2b-account-service                                                [jar]
[INFO] b2b-order-service                                                  [jar]
[INFO]
[INFO] ------------------< com.javacode2018:b2b-account-api >------------------
[INFO] Building b2b-account-api 1.0-SNAPSHOT                              [1/3]
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ b2b-account-api ---
[INFO] Deleting D:\code\IdeaProjects\b2b\b2b-account\b2b-account-api\target
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ b2b-account-api ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] Copying 0 resource
[INFO]
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ b2b-account-api ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ b2b-account-api ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory D:\code\IdeaProjects\b2b\b2b-account\b2b-account-api\src\test\resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ b2b-account-api ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ b2b-account-api ---
[INFO] No tests to run.
[INFO]
[INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ b2b-account-api ---
[INFO] Building jar: D:\code\IdeaProjects\b2b\b2b-account\b2b-account-api\target\b2b-account-api-1.0-SNAPSHOT.jar
[INFO]
[INFO] --- maven-install-plugin:2.4:install (default-install) @ b2b-account-api ---
[INFO] Installing D:\code\IdeaProjects\b2b\b2b-account\b2b-account-api\target\b2b-account-api-1.0-SNAPSHOT.jar to C:\Users\Think\.m2\repository\com\javacode2018\b2b-account-api\1.0-SNAPSHOT\b2b-account-api-1.0-SNAPSHOT.jar
[INFO] Installing D:\code\IdeaProjects\b2b\b2b-account\b2b-account-api\pom.xml to C:\Users\Think\.m2\repository\com\javacode2018\b2b-account-api\1.0-SNAPSHOT\b2b-account-api-1.0-SNAPSHOT.pom
[INFO]
[INFO] ----------------< com.javacode2018:b2b-account-service >----------------
[INFO] Building b2b-account-service 1.0-SNAPSHOT                          [2/3]
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ b2b-account-service ---
[INFO] Deleting D:\code\IdeaProjects\b2b\b2b-account\b2b-account-service\target
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ b2b-account-service ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] Copying 0 resource
[INFO]
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ b2b-account-service ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ b2b-account-service ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory D:\code\IdeaProjects\b2b\b2b-account\b2b-account-service\src\test\resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ b2b-account-service ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ b2b-account-service ---
[INFO] No tests to run.
[INFO]
[INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ b2b-account-service ---
[INFO] Building jar: D:\code\IdeaProjects\b2b\b2b-account\b2b-account-service\target\b2b-account-service-1.0-SNAPSHOT.jar
[INFO]
[INFO] --- maven-install-plugin:2.4:install (default-install) @ b2b-account-service ---
[INFO] Installing D:\code\IdeaProjects\b2b\b2b-account\b2b-account-service\target\b2b-account-service-1.0-SNAPSHOT.jar to C:\Users\Think\.m2\repository\com\javacode2018\b2b-account-service\1.0-SNAPSHOT\b2b-account-service-1.0-SNAPSHOT.jar
[INFO] Installing D:\code\IdeaProjects\b2b\b2b-account\b2b-account-service\pom.xml to C:\Users\Think\.m2\repository\com\javacode2018\b2b-account-service\1.0-SNAPSHOT\b2b-account-service-1.0-SNAPSHOT.pom
[INFO]
[INFO] -----------------< com.javacode2018:b2b-order-service >-----------------
[INFO] Building b2b-order-service 1.0-SNAPSHOT                            [3/3]
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ b2b-order-service ---
[INFO] Deleting D:\code\IdeaProjects\b2b\b2b-order\b2b-order-service\target
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ b2b-order-service ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] Copying 0 resource
[INFO]
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ b2b-order-service ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ b2b-order-service ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory D:\code\IdeaProjects\b2b\b2b-order\b2b-order-service\src\test\resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ b2b-order-service ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ b2b-order-service ---
[INFO] No tests to run.
[INFO]
[INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ b2b-order-service ---
[INFO] Building jar: D:\code\IdeaProjects\b2b\b2b-order\b2b-order-service\target\b2b-order-service-1.0-SNAPSHOT.jar
[INFO]
[INFO] --- maven-install-plugin:2.4:install (default-install) @ b2b-order-service ---
[INFO] Installing D:\code\IdeaProjects\b2b\b2b-order\b2b-order-service\target\b2b-order-service-1.0-SNAPSHOT.jar to C:\Users\Think\.m2\repository\com\javacode2018\b2b-order-service\1.0-SNAPSHOT\b2b-order-service-1.0-SNAPSHOT.jar
[INFO] Installing D:\code\IdeaProjects\b2b\b2b-order\b2b-order-service\pom.xml to C:\Users\Think\.m2\repository\com\javacode2018\b2b-order-service\1.0-SNAPSHOT\b2b-order-service-1.0-SNAPSHOT.pom
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary for b2b-account-api 1.0-SNAPSHOT:
[INFO]
[INFO] b2b-account-api .................................... SUCCESS [  2.440 s]
[INFO] b2b-account-service ................................ SUCCESS [  0.381 s]
[INFO] b2b-order-service .................................. SUCCESS [  0.364 s]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  3.508 s
[INFO] Finished at: 2019-11-20T16:05:00+08:00
[INFO] ------------------------------------------------------------------------

从上面输出中看一下反应堆列出的构建顺序：b2b-account-api、b2b-account-service、b2b-order-service。

上面过程给大家捋一捋：

上面命令先会运行-pl b2b-account-api得到一个反应堆列表，如下，只有一个模块：

b2b-account-api

然后后面又会执行amd，这个命令会找到对-pl b2b-account-api有依赖的构件，也就是：

b2b-account-service
b2b-order-serivce

然后反应堆会对3个构件进行排序，得到一个正确的构件顺序，如下：

[INFO] Reactor Build Order:
[INFO]
[INFO] b2b-account-api                                                    [jar]
[INFO] b2b-account-service                                                [jar]
[INFO] b2b-order-service                                                  [jar]

然后maven会依次对他们执行：

mvn clean install

案例5

需求：我们来构建b2b-order-service，希望b2b-account-service依赖的构件也能被同时构建，b2b-account-service依赖于b2b-account-api和b2b-order-api，可能b2b-account-service会依赖的更多。

可以使用下面命令：

mvn clean install -pl b2b-order/b2b-order-service -am

效果如下：

D:\code\IdeaProjects\b2b>mvn clean install -pl b2b-order/b2b-order-service -am
[INFO] Scanning for projects...
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Build Order:
[INFO]
[INFO] b2b-account-api                                                    [jar]
[INFO] b2b-order-api                                                      [jar]
[INFO] b2b-order-service                                                  [jar]
[INFO]
[INFO] ------------------< com.javacode2018:b2b-account-api >------------------
[INFO] Building b2b-account-api 1.0-SNAPSHOT                              [1/3]
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ b2b-account-api ---
[INFO] Deleting D:\code\IdeaProjects\b2b\b2b-account\b2b-account-api\target
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ b2b-account-api ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] Copying 0 resource
[INFO]
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ b2b-account-api ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ b2b-account-api ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory D:\code\IdeaProjects\b2b\b2b-account\b2b-account-api\src\test\resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ b2b-account-api ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ b2b-account-api ---
[INFO] No tests to run.
[INFO]
[INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ b2b-account-api ---
[INFO] Building jar: D:\code\IdeaProjects\b2b\b2b-account\b2b-account-api\target\b2b-account-api-1.0-SNAPSHOT.jar
[INFO]
[INFO] --- maven-install-plugin:2.4:install (default-install) @ b2b-account-api ---
[INFO] Installing D:\code\IdeaProjects\b2b\b2b-account\b2b-account-api\target\b2b-account-api-1.0-SNAPSHOT.jar to C:\Users\Think\.m2\repository\com\javacode2018\b2b-account-api\1.0-SNAPSHOT\b2b-account-api-1.0-SNAPSHOT.jar
[INFO] Installing D:\code\IdeaProjects\b2b\b2b-account\b2b-account-api\pom.xml to C:\Users\Think\.m2\repository\com\javacode2018\b2b-account-api\1.0-SNAPSHOT\b2b-account-api-1.0-SNAPSHOT.pom
[INFO]
[INFO] -------------------< com.javacode2018:b2b-order-api >-------------------
[INFO] Building b2b-order-api 1.0-SNAPSHOT                                [2/3]
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ b2b-order-api ---
[INFO] Deleting D:\code\IdeaProjects\b2b\b2b-order\b2b-order-api\target
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ b2b-order-api ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] Copying 0 resource
[INFO]
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ b2b-order-api ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ b2b-order-api ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory D:\code\IdeaProjects\b2b\b2b-order\b2b-order-api\src\test\resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ b2b-order-api ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ b2b-order-api ---
[INFO] No tests to run.
[INFO]
[INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ b2b-order-api ---
[INFO] Building jar: D:\code\IdeaProjects\b2b\b2b-order\b2b-order-api\target\b2b-order-api-1.0-SNAPSHOT.jar
[INFO]
[INFO] --- maven-install-plugin:2.4:install (default-install) @ b2b-order-api ---
[INFO] Installing D:\code\IdeaProjects\b2b\b2b-order\b2b-order-api\target\b2b-order-api-1.0-SNAPSHOT.jar to C:\Users\Think\.m2\repository\com\javacode2018\b2b-order-api\1.0-SNAPSHOT\b2b-order-api-1.0-SNAPSHOT.jar
[INFO] Installing D:\code\IdeaProjects\b2b\b2b-order\b2b-order-api\pom.xml to C:\Users\Think\.m2\repository\com\javacode2018\b2b-order-api\1.0-SNAPSHOT\b2b-order-api-1.0-SNAPSHOT.pom
[INFO]
[INFO] -----------------< com.javacode2018:b2b-order-service >-----------------
[INFO] Building b2b-order-service 1.0-SNAPSHOT                            [3/3]
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ b2b-order-service ---
[INFO] Deleting D:\code\IdeaProjects\b2b\b2b-order\b2b-order-service\target
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ b2b-order-service ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] Copying 0 resource
[INFO]
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ b2b-order-service ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ b2b-order-service ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory D:\code\IdeaProjects\b2b\b2b-order\b2b-order-service\src\test\resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ b2b-order-service ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ b2b-order-service ---
[INFO] No tests to run.
[INFO]
[INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ b2b-order-service ---
[INFO] Building jar: D:\code\IdeaProjects\b2b\b2b-order\b2b-order-service\target\b2b-order-service-1.0-SNAPSHOT.jar
[INFO]
[INFO] --- maven-install-plugin:2.4:install (default-install) @ b2b-order-service ---
[INFO] Installing D:\code\IdeaProjects\b2b\b2b-order\b2b-order-service\target\b2b-order-service-1.0-SNAPSHOT.jar to C:\Users\Think\.m2\repository\com\javacode2018\b2b-order-service\1.0-SNAPSHOT\b2b-order-service-1.0-SNAPSHOT.jar
[INFO] Installing D:\code\IdeaProjects\b2b\b2b-order\b2b-order-service\pom.xml to C:\Users\Think\.m2\repository\com\javacode2018\b2b-order-service\1.0-SNAPSHOT\b2b-order-service-1.0-SNAPSHOT.pom
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary for b2b-account-api 1.0-SNAPSHOT:
[INFO]
[INFO] b2b-account-api .................................... SUCCESS [  2.509 s]
[INFO] b2b-order-api ...................................... SUCCESS [  0.343 s]
[INFO] b2b-order-service .................................. SUCCESS [  0.340 s]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  3.455 s
[INFO] Finished at: 2019-11-20T16:46:45+08:00
[INFO] ------------------------------------------------------------------------

从上面输出中看一下反应堆列出的构建顺序：b2b-account-api、b2b-order-api、b2b-order-service。

上面过程给大家捋一捋：

上面命令先会运行-pl b2b-order-service得到一个反应堆列表：

b2b-order-service

然后后面又会执行am，这个命令会找到-pl b2b-order-service依赖的构件，也就是：

b2b-account-api
b2b-order-api

然后反应堆会对3个构件进行排序，得到一个正确的构件顺序，如下：

[INFO] Reactor Build Order:
[INFO]
[INFO] b2b-account-api                                                    [jar]
[INFO] b2b-order-api                                                      [jar]
[INFO] b2b-order-service                                                  [jar]

然后maven会依次对他们执行：

mvn clean install

案例6

分别执行下面2条mvn命令，先看一下效果：

mvn clean install
mvn clean install -rf b2b-order/b2b-order-service

输出中我们取出部分内容，如下。

第一条命令，反应堆产生的构建顺序是：

[INFO] Reactor Build Order:
[INFO]
[INFO] b2b-account-api                                                    [jar]
[INFO] b2b-account-service                                                [jar]
[INFO] b2b-account                                                        [pom]
[INFO] b2b-order-api                                                      [jar]
[INFO] b2b-order-service                                                  [jar]
[INFO] b2b-order                                                          [pom]
[INFO] b2b                                                                [pom]

第2条命令，反应堆产生的构建顺序是：

[INFO] Reactor Build Order:
[INFO]
[INFO] b2b-order-service                                                  [jar]
[INFO] b2b-order                                                          [pom]
[INFO] b2b                                                                [pom]

在仔细看一下上面2条命令的差别，后面的命令多了-rf b2b-order/b2b-order-service，具体过程如下：

会先执行下面命令

mvn clean install

反应堆会计算出需要构件的模块顺序，如下：

[INFO] Reactor Build Order:
[INFO]
[INFO] b2b-account-api                                                    [jar]
[INFO] b2b-account-service                                                [jar]
[INFO] b2b-account                                                        [pom]
[INFO] b2b-order-api                                                      [jar]
[INFO] b2b-order-service                                                  [jar]
[INFO] b2b-order                                                          [pom]
[INFO] b2b                                                                [pom]

-rf b2b-order/b2b-order-service对上面的反应堆构件顺序进行裁剪，将b2b-order/b2b-order-service前面的部分干掉，从b2b-order/b2b-order-service开始执行构建操作，所以剩下了3个需要构建的模块。

总结

  1. 需要掌握mvn命令中-pl、-am、-amd、-rf的各种用法

  2. 注意-pl后面的参数的写法：模块相对路径、或者[groupId].artifactId

还是那句话，上面这些用法大家会经常用到的，建议大家下去了多练练。看和操作，所获取到的是不能比的，看的过程中可能觉得一切都知道了，但是实际操作就不一样了，可能中间会遇到各种问题，然后自己会想办法解决这些问题，领会和学到的东西是不一样的！

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