spring boot 入门之 helloworld

第一步：创建一个普通的maven项目 

第二步：配置springboot基础依赖配置（即配置pom和启动类）

POM配置

<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>spring-boot-example</groupId>
  <artifactId>spring-boot-example</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <name>spring-boot-example</name>
  <description>spring-boot-example</description>
  
  <!-- 继承父包 -->
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.19.RELEASE</version>
        <relativePath></relativePath>
    </parent>
  
  <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>
  
  <properties>
        <java.version>1.8</java.version>
  </properties>

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

配置启动类

@RestController      // @RestController  相当于 @Controller 加上  @ResponseBody
@EnableAutoConfiguration
public class HelloController {

    public static void main(String[] args) {
        SpringApplication.run(HelloController.class, args);
    }
    
    @RequestMapping("/example/hello")
    public int hello(){
        return 1;
    }

}

最后，启动springboot应用

方式一：eclipse中直接运行main方法

方式二：命令行执行  java -jar spring-boot-example.jar &

方式三：打包成war文件，放tomcat中运行

结果如下图所示：

发布的http服务测试：http://localhost:8080/example/hello，测试成功！，如下图所示

关于打包成war形式，放入tomcat中运行需要注意：

第一步：修改pom文件：新增黑色字体部分内容

<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>spring-boot-example</groupId>
  <artifactId>spring-boot-example</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <name>spring-boot-example</name>
  <description>spring-boot-example</description>
  <packaging>war</packaging>
  
  <!-- 继承父包 -->
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.19.RELEASE</version>
        <relativePath></relativePath>
    </parent>
  
  <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>
        
        <!-- 确保内置servlet container 不会干涉发布该war包的servlet container，方案是标记内置servlet container 的依赖为    provided -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
            <scope>provided</scope>
        </dependency>
  </dependencies>

第二步：更改程序入口类 Application.java 使其继承SpringBootServletInitializer，并重写configure方法，（即加粗字体部分）

@RestController      // @RestController  相当于 @Controller 加上  @ResponseBody
@SpringBootApplication
public class HelloController extends SpringBootServletInitializer{

    @Override
    public SpringApplicationBuilder configure(SpringApplicationBuilder application){
        return  application.sources(HelloController.class);
    }
    
    public static void main(String[] args) {
        SpringApplication.run(HelloController.class, args);
    }
    
    @RequestMapping("/example/hello")
    public int hello(){
        return 1;
    }
}

用 tomcat验证结果：