Maven+mybatis - 技术栈

maven：使用java语言编写的基于项目对象模型的项目管理工具软件

maven的仓库：中央仓库，本地仓库，镜像仓库

maven的资源坐标：

GroupId：一般是逆向公司域名com.zrt

ArtifactId：一般是项目（jar）名mysql-connector-java.

Version：版本号8.0.28

框架：

重复基础代码封装，同时添加额外功能

Mybatis:

持久层框架（数据库连接框架），ORM框架（对象/关系映射）

1.创建数据库表

2.创建maven项目

3.添加依赖

在pol.xml文件中配置

XML 复制代码

<dependencies>
    <!-- mysql驱动的依赖 -->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>8.0.28</version>
    </dependency>

    <!-- Mybatis依赖 -->
    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis</artifactId>
        <version>3.5.6</version>
    </dependency>
</dependencies>

4.创建mybatis全局配置文件

在resources文件中配置xml文件

XML 复制代码

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "https://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
//环境配置
    <environments default="mysql">//默认链接mysql
        <environment id="mysql">
            <transactionManager type="JBDC"></transactionManager>//事务处理jdbc/manager
            <dataSource type="POOLED">//数据源信息UNPOOLED/POOLED/JNDI（POOLED 数据库连接池，数据库连接请求频率高就要用到）
                <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/bookmanager?useSSL=false&amp;serverTimezone=UTC&amp;allowPublicKeyRetrieval=true"/>
                <property name="username" value="root"/>
                <property name="password" value="zrt20031002"/>
            </dataSource>
        </environment>
    </environments>
</configuration>

5.创建实体类

java 复制代码

//要和数据库中列明保持一致
public class Book {
    private int id;
    private String name;
    private String author;
    private double price;

    public int getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public String getAuthor() {
        return author;
    }

    public double getPrice() {
        return price;
    }

    public void setId(int id) {
        this.id = id;
    }

    public void setName(String name) {
        this.name = name;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

    public void setPrice(double price) {
        this.price = price;
    }

    public Book(int id, String name, String author, double price) {
        this.id = id;
        this.name = name;
        this.author = author;
        this.price = price;
    }
}

6.创建映射文件

XML 复制代码

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "https://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper>
    <select id="selectAllBooks" resultType="com.zrt.pojo.Book">
        select * from t_book
    </select>
</mapper>

把映射文件放到mysatis配置文件中去，就能实现mysatis项目加载映射文件

XML 复制代码

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "https://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <environments default="mysql">
        <environment id="mysql">
            <transactionManager type="JBDC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/bookmanager?useSSL=false&amp;serverTimezone=UTC&amp;allowPublicKeyRetrieval=true"/>
                <property name="username" value="root"/>
                <property name="password" value="zrt20031002"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="mapper/BookMapper.xml"></mapper>
    </mappers>
</configuration>

7.编写测试类------自动项目

java 复制代码

package com.zrt.test;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

public class Test {
    public static void main(String[] args) throws IOException {
        //指定核心配置文件的路径：
        String resource = "mybatis.xml";
        //获取加载配置文件的一个输入流：
        InputStream inputStream = Resources.getResourceAsStream(resource);
        //加载配置文件，创建工厂类
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        //通过工厂类获取一个会话：
        SqlSession sqlSession = sqlSessionFactory.openSession();
        //执行查询语句
        List<com.zrt.pojo.Book> list = sqlSession.selectList("a.b.selectAllBooks");
        //遍历：
        for (com.zrt.pojo.Book book : list) {
            System.out.println(book.getId() + "---" + book.getName() + "---" + book.getAuthor() + "---" + book.getPrice());
        }
            //关闭会话
        sqlSession.close();
    }
}