1.自定義啓動器starter

 

1. 新建maven工程yahang-spring-boot-starter (starter是一個空JAR包，僅僅作爲maven下載jar包的啓動器)
2. 新建maven工程yahang-spring-boot-starter-autoconfigure (實際工作的模塊)
3. yahang-spring-boot-starter作爲一個啓動器，設置依賴於yahang-spring-boot-starter-autoconfigure
4.     <dependency>

          <groupId>com.njupt</groupId>

          <artifactId>yahang-spring-boot-starter-autoconfigure</artifactId>

          <version>0.0.1-SNAPSHOT</version>

       </dependency>
5. yahang-spring-boot-starter-autoconfigure模塊下，設置依賴於spring-boot-starter
6.      <dependency>

            <groupId>org.springframework.boot</groupId>

            <artifactId>spring-boot-starter</artifactId>

            <version>2.3.0.RELEASE</version>

        </dependency>
7. yahang-spring-boot-starter-autoconfigure模塊下，新建包com.njupt,然後新建一個實體類，該實體類爲要配置爲bean的類
   1. public class MyDataSource {
   2.     public String url;
   3.     public String username;
   4.     public String password;
   5.     public MyDataSource(String url, String username, String password) {
   6.         super();
   7.         this.url = url;
   8.         this.username = username;
   9.         this.password = password;
   10.     }  
   11. }
8. yahang-spring-boot-starter-autoconfigure模塊下的com.njupt包下,然後新建一個MyDataSourceProperties類，該實體類爲讀取yml文件的類，並設置getter,setter方法。
   1. @ConfigurationProperties(prefix = "yahang.mydatasource")
   2. public class MyDataSourceProperties {
   3.     private String url;
   4.     private String username;
   5.     private String password;
9. yahang-spring-boot-starter-autoconfigure模塊下的com.njupt包下,然後新建一個MyDataSourceAutoConfigure類，該類使用MyDataSourceProperties對象的屬性，new MyDataSource對象，並注入爲Bean
   1. @Configuration
   2. @ConditionalOnWebApplication
   3. @EnableConfigurationProperties(MyDataSourceProperties.class)
   4. public class MyDataSourceAutoConfigure {
   5.    
   6.     @Autowired
   7.     private MyDataSourceProperties myDataSourceProperties;
   8.    
   9.     @Bean
   10.     public MyDataSource getDataSource() {
   11.         String url=myDataSourceProperties.getUrl();
   12.         String username=myDataSourceProperties.getUsername();
   13.         String password=myDataSourceProperties.getPassword();
   14.         return new MyDataSource(url, username, password);
   15.     }
   16. }
10. 爲了讓Springboot加載MyDataSourceAutoConfigure，需要在resources目錄下新建META-INF/spring.factories
    1. org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
    2. com.njupt.MyDataSourceAutoConfigure
11. 使用maven install 安裝autoconfigure和starter模塊。
12. 測試
     
    1. 新建Springboot的web應用，pom文件引入自定義的starter
    2.         <dependency>

                 <groupId>com.njupt</groupId>

                 <artifactId>yahang-spring-boot-starter</artifactId>

                 <version>0.0.1-SNAPSHOT</version>

                 </dependency>
    3. 編寫application.yml
       1. yahang:
       2.   mydatasource:
       3.     url: localhaost
       4.     username: yahang
       5.     password: 123456
    4. 編寫測試代碼
       1. @Controller
       2. public class MyController {
       3.    
       4.     @Autowired
       5.     private MyDataSource dataSource;
       6.     @ResponseBody
       7.     @RequestMapping("/test")
       8.     public String getDatasource() {
       9.         return dataSource.url+" : "+ dataSource.username+" : "+dataSource.password;
       10.     }
       11. }
    5. 測試