搭建SpringBoot工程步骤

建构工程步骤

打开Idea-> new Project ->Spring Initializr ->填写group、artifact ->钩上web(开启web功能）->点下一步就行了。

工程目录

创建完工程，工程的目录结构如下：

yaml 复制代码

- src
	-main
		-java
			-package
				-SpringbootApplication
		-resouces
			- statics
			- templates
			- application.yml
	-test
- pom

pom文件为基本的依赖管理文件
resouces 资源文件
- statics 静态资源
- templates 模板资源
- application.yml 配置文件
SpringbootApplication程序的入口。

pom.xml的依赖：

java 复制代码

<?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.forezp</groupId>
	<artifactId>springboot-first-application</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>jar</packaging>

	<name>springboot-first-application</name>
	<description>Demo project for Spring Boot</description>

	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>1.5.2.RELEASE</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>

	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
		<java.version>1.8</java.version>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>


</project>

其中spring-boot-starter-web不仅包含spring-boot-starter,还自动开启了web功能。

功能演示

说了这么多，你可能还体会不到，举个栗子，比如你引入了Thymeleaf的依赖，spring boot 就会自动帮你引入SpringTemplateEngine，当你引入了自己的SpringTemplateEngine，spring boot就不会帮你引入。它让你专注于你的自己的业务开发，而不是各种配置。

再举个栗子,建个controller：

java 复制代码

import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.bind.annotation.RequestMapping;

@RestController
public class HelloController {

    @RequestMapping("/")
    public String index() {
        return "Greetings from Spring Boot!";
    }

}

启动SpringbootFirstApplication的main方法，打开浏览器localhost:8080,浏览器显示：

Greetings from Spring Boot!

神奇之处：

你没有做任何的web.xml配置。
你没有做任何的sping mvc的配置; springboot为你做了。
你没有配置tomcat ;springboot内嵌tomcat.

启动springboot 方式

cd到项目主目录:

mvn clean  
mvn package  编译项目的jar

mvn spring-boot: run 启动
cd 到target目录，java -jar 项目.jar

来看看springboot在启动的时候为我们注入了哪些bean

在程序入口加入：

java 复制代码

@SpringBootApplication
public class SpringbootFirstApplication {

	public static void main(String[] args) {
		SpringApplication.run(SpringbootFirstApplication.class, args);
	}

	@Bean
	public CommandLineRunner commandLineRunner(ApplicationContext ctx) {
		return args -> {

			System.out.println("Let's inspect the beans provided by Spring Boot:");

			String[] beanNames = ctx.getBeanDefinitionNames();
			Arrays.sort(beanNames);
			for (String beanName : beanNames) {
				System.out.println(beanName);
			}

		};
	}

}

程序输出：

Let's inspect the beans provided by Spring Boot: basicErrorController beanNameHandlerMapping beanNameViewResolver characterEncodingFilter commandLineRunner conventionErrorViewResolver defaultServletHandlerMapping defaultViewResolver dispatcherServlet dispatcherServletRegistration duplicateServerPropertiesDetector embeddedServletContainerCustomizerBeanPostProcessor error errorAttributes errorPageCustomizer errorPageRegistrarBeanPostProcessor
.... ....

在程序启动的时候，springboot自动诸如注入了40-50个bean.

单元测试

通过@RunWith() @SpringBootTest开启注解：

java 复制代码

@RunWith(SpringRunner.class)
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
public class HelloControllerIT {

    @LocalServerPort
    private int port;

    private URL base;

    @Autowired
    private TestRestTemplate template;

    @Before
    public void setUp() throws Exception {
        this.base = new URL("http://localhost:" + port + "/");
    }

    @Test
    public void getHello() throws Exception {
        ResponseEntity<String> response = template.getForEntity(base.toString(),
                String.class);
        assertThat(response.getBody(), equalTo("Greetings from Spring Boot!"));
    }
}