SpringBoot封装自己的starter

        本文演示如何封装自己的SpringBoot starter。

一、新建一个SpringBoot项目my-spring-boot-starter

项目目录结构如下：

二、项目依赖文件

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.6.7</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <groupId>com.example</groupId>
    <artifactId>my-spring-boot-starter</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>my-spring-boot-starter</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
    </dependencies>

</project>

三、resources目录下添加目录META-INF下的文件spring.factories

org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
  com.example.myspringbootstarter.MyServiceAutoConfiguration

         读者可以查看SpringBoot自动配置原理，即可明白此处配置。此处MyServiceAutoConfiguration类为配置类，并将MyService交给Spring管理。

四、编写代码配置类和测试接口

public class MyService {

    public String hello(String name){
        return "Hello "+ name + " !";
    }
}


@Configuration
@ConditionalOnWebApplication
public class MyServiceAutoConfiguration {

    @Bean
    public MyService hello(){
        return new MyService();
    }
}

 五、新建测试工程，引入自定义starter的依赖

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.6.7</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.my</groupId>
    <artifactId>springboot-starter-test</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>springboot-starter-test</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>com.example</groupId>
            <artifactId>my-spring-boot-starter</artifactId>
            <version>0.0.1-SNAPSHOT</version>
        </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>

此处引入自定义的starter依赖（使用Maven工具install原starter项目）：

        <dependency>
            <groupId>com.example</groupId>
            <artifactId>my-spring-boot-starter</artifactId>
            <version>0.0.1-SNAPSHOT</version>
        </dependency>

说明：引入自定义starter后，在项目的依赖下可以查看到：

六、编写测试类

@RestController
public class TestController {

    @Autowired
    private MyService myService;

    @GetMapping("/hello")
    public String hello(@RequestParam(value = "name") String name){
        return myService.hello(name);
    }
}

七、启动测试项目并测试

        至此，封装自己的SpringBoot starter成功！