Spring Boot自定义Starter

文章目录

1. 1. 一、maven依赖
2. 2. 二、设置配置文件相应类目的前缀
3. 3. 三、编写AutoConfigure类
4. 4. 四、在resources/META-INF/下创建spring.factories文件
5. 5. 五、原理
6. 6. 六、鸣谢

一、maven依赖

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-autoconfigure</artifactId>
    </dependency>
</dependencies>

二、设置配置文件相应类目的前缀

@ConfigurationProperties("example.service")
public class ExampleServiceProperties {
    private String prefix;
    private String suffix;
    //省略 getter setter

三、编写AutoConfigure类

@Configuration
//当classpath下发现该类的情况下进行自动配置
@ConditionalOnClass(ExampleService.class)
@EnableConfigurationProperties(ExampleServiceProperties.class)
public class ExampleAutoConfigure {

    @Autowired
    private ExampleServiceProperties properties;

    @Bean
    //当Spring Context中不存在该Bean时
    @ConditionalOnMissingBean
    //当配置文件中example.service.enabled=true时
    @ConditionalOnProperty(prefix = "example.service",value = "enabled",havingValue = "true")
    ExampleService exampleService (){
        return  new ExampleService(properties.getPrefix(),properties.getSuffix());
    }

}

四、在resources/META-INF/下创建spring.factories文件

org.springframework.boot.autoconfigure.EnableAutoConfiguration=com.example.autocinfigure.ExampleAutoConfigure

五、原理

1. Spring Boot在启动时扫描项目所依赖的JAR包，寻找包含spring.factories文件的JAR包
2. 根据spring.factories配置加载AutoConfigure类
3. 根据 @Conditional注解的条件，进行自动配置并将Bean注入Spring Context

六、鸣谢

http://www.jianshu.com/p/45538b44e04e