编写场景启动器（starter）需要注意其层级关系、需要使用到的依赖、自动配置的实现等。

  1. @Configuration  //指定这个类是一个配置类
  2. @ConditionalOnXXX  //在指定条件成立的情况下自动配置类生效
  3. @AutoConfigureAfter  //指定自动配置类的顺序
  4. @Bean  //给容器中添加组件
  5. @ConfigurationPropertie结合相关xxxProperties类来绑定相关的配置
  6. @EnableConfigurationProperties //让xxxProperties生效加入到容器中
  7. 自动配置类要能加载
  8. 将需要启动就加载的自动配置类，配置在META-INF/spring.factories
  9. org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
  10. org.springframework.boot.autoconfigure.admin.SpringApplicationAdminJmxAutoConfiguration,\
  11. org.springframework.boot.autoconfigure.aop.AopAutoConfiguration,\

步骤说明

image.png
启动器只用来做依赖导入，需要专门来写一个自动配置模块。启动器依赖自动配置，其他项目需要使用改模块只需要引入启动器（starter）即可。

1、启动器模块

  1. <?xml version="1.0" encoding="UTF-8"?>
  2. <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  3.          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  4.     <modelVersion>4.0.0</modelVersion>
  5.     <groupId>com.gmd.starter</groupId>
  6.     <artifactId>gmd-spring-boot-starter</artifactId>
  7.     <version>1.0-SNAPSHOT</version>
  8.     <!--启动器-->
  9.     <dependencies>
  10.         <!--引入自动配置模块-->
  11.         <dependency>
  12.             <groupId>com.gmd.starter</groupId>
  13.             <artifactId>gmd-spring-boot-starter-autoconfigurer</artifactId>
  14.             <version>0.0.1-SNAPSHOT</version>
  15.         </dependency>
  16.     </dependencies>
  17. </project>

2、自动配置模块

  1. <?xml version="1.0" encoding="UTF-8"?>
  2. <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  3.    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  4.    <modelVersion>4.0.0</modelVersion>
  5.    <groupId>com.gmd.starter</groupId>
  6.    <artifactId>gmd-spring-boot-starter-autoconfigurer</artifactId>
  7.    <version>0.0.1-SNAPSHOT</version>
  8.    <packaging>jar</packaging>
  9.    <name>gmd-spring-boot-starter-autoconfigurer</name>
  10.    <description>Demo project for Spring Boot</description>
  11.    <parent>
  12.       <groupId>org.springframework.boot</groupId>
  13.       <artifactId>spring-boot-starter-parent</artifactId>
  14.       <version>1.5.10.RELEASE</version>
  15.       <relativePath/> <!-- lookup parent from repository -->
  16.    </parent>
  17.    <properties>
  18.       <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  19.       <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
  20.       <java.version>1.8</java.version>
  21.    </properties>
  22.    <dependencies>
  23.       <!--引入spring-boot-starter；所有starter的基本配置-->
  24.       <dependency>
  25.          <groupId>org.springframework.boot</groupId>
  26.          <artifactId>spring-boot-starter</artifactId>
  27.       </dependency>
  28.    </dependencies>
  29. </project>
package com.gmd.starter;
import org.springframework.boot.context.properties.ConfigurationProperties;
@ConfigurationProperties(prefix = "gmd.hello")
public class HelloProperties {
    private String prefix;
    private String suffix;
    public String getPrefix() {
        return prefix;
    }
    public void setPrefix(String prefix) {
        this.prefix = prefix;
    }
    public String getSuffix() {
        return suffix;
    }
    public void setSuffix(String suffix) {
        this.suffix = suffix;
    }
}

package com.gmd.starter;
public class HelloService {
    HelloProperties helloProperties;
    public HelloProperties getHelloProperties() {
        return helloProperties;
    }
    public void setHelloProperties(HelloProperties helloProperties) {
        this.helloProperties = helloProperties;
    }
    public String sayHello(String name){
        return helloProperties.getPrefix()+"-" +name + helloProperties.getSuffix();
    }
}

package com.gmd.starter;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
@ConditionalOnWebApplication //web应用才生效
@EnableConfigurationProperties(HelloProperties.class)
public class HelloServiceAutoConfiguration {
    @Autowired
    HelloProperties helloProperties;
    @Bean
    public HelloService helloService(){
        HelloService service = new HelloService();
        service.setHelloProperties(helloProperties);
        return service;
    }
}

3、测试
将该项目安装到maven仓库中，然后另起一项目依赖该自定义的场景启动器。

更多SpringBoot整合示例：
https://github.com/spring-projects/spring-boot/tree/master/spring-boot-samples

尚硅谷SpringBoot学习教程代码：
https://github.com/mxg133/learnforSpringBoot