<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>org.elvin</groupId>
 <artifactId>my-spring-boot-starter</artifactId>
 <version>1.0-SNAPSHOT</version>
 <packaging>jar</packaging>
 <name>my-spring-boot-starter</name>
 <url>http://maven.apache.org</url>
 <properties>
 <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 </properties>
 <dependencies>
 <dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-autoconfigure</artifactId>
 <version>1.5.9.RELEASE</version>
 </dependency>
 <dependency>
 <groupId>junit</groupId>
 <artifactId>junit</artifactId>
 <version>3.8.1</version>
 <scope>test</scope>
 </dependency>
 </dependencies>
 <build>
 <plugins>
 <plugin>
 <groupId>org.apache.maven.plugins</groupId>
 <artifactId>maven-compiler-plugin</artifactId>
 <version>2.3.2</version>
 <configuration>
  <source>1.8</source>
  <target>1.8</target>
 </configuration>
 </plugin>
 </plugins>
 </build>
</project>

package org.elvin;
import org.springframework.boot.context.properties.ConfigurationProperties;/**
 * author: Elvin
 * Date: 2017/12/12 14:51
 * Description:
 */
@ConfigurationProperties(prefix = "hello")
public class HelloServiceProperties {
 //默认配置内容
 private static final String MSG = "world";
 private String msg = MSG;
 public String getMsg() {
 return msg;
 }
 public void setMsg(String msg) {
 this.msg = msg;
 }
}

package org.elvin;
/**
 * author: Elvin
 * Date: 2017/12/12 14:55
 * Description:
 */
public class HelloService {
 private String msg;
 public String sayHello(){
 return "Hello " + msg;
 }
 public String getMsg() {
 return msg;
 }
 public void setMsg(String msg) {
 this.msg = msg;
 }
}

package org.elvin;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
/**
 * author: Elvin
 * Date: 2017/12/12 14:59
 * Description:
 */
@Configuration
@EnableConfigurationProperties(HelloServiceProperties.class)
@ConditionalOnClass(HelloService.class)
@ConditionalOnProperty(prefix = "hello", value="enabled", matchIfMissing =true )
public class HelloServiceAutoConfiguration {
 @Autowired
 private HelloServiceProperties helloServiceProperties;
 @Bean
 @ConditionalOnMissingBean(HelloService.class)
 public HelloService helloService(){
 HelloService helloService = new HelloService();
 helloService.setMsg(helloServiceProperties.getMsg());
 return helloService;
 }
}

org.springframework.boot.autoconfigure.EnableAutoConfiguration=org.elvin.HelloServiceAutoConfiguration

<dependency>
   <groupId>org.elvin</groupId>
   <artifactId>my-spring-boot-starter</artifactId>
   <version>1.0-SNAPSHOT</version>
  </dependency>

package org.elvin.learn.springboot.controller;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.elvin.*;
/**
 * author: Elvin
 * Date: 2017/12/12 15:34
 * Description:
 */
@RestController
@RequestMapping("hello")
public class HelloController {
 @Autowired
 private HelloService helloService;
 @RequestMapping("index")
 public String index(){
  return helloService.sayHello();
 }
}