spring学习--11 composite annotation and meta annotation

组合注解与其注解的注解具有相同的作用

1. 组合注解

package com.annotation;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Configuration
@ComponentScan
public @interface CompositeConfiguration {
    String[] values() default {};
}

2. Service类

package com.annotation;

import org.springframework.stereotype.Service;

@Service
public class DemoService {
    public void outputResult() {
        System.out.println("We can also get bean from composite annotation.");
    }
}

3. Configuration annotated by composite annotation

package com.annotation;

@CompositeConfiguration
public class DemoConfig {

}

4. Test

package com.annotation;

import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = {DemoConfig.class})
public class Bootrap {
    @Autowired
    DemoService service;

    @org.junit.Test
    public void test() {
        service.outputResult();
    }
}