使用Spring获得包含自定义注解的对象

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直接上代码比较容易理解。

RpcService.java

package com.mrbcy.bigdata.basic.spring.annotation;import java.lang.annotation.ElementType;import java.lang.annotation.Retention;import java.lang.annotation.RetentionPolicy;import java.lang.annotation.Target;import org.springframework.stereotype.Component;@Target({ ElementType.TYPE })//注解用在接口上@Retention(RetentionPolicy.RUNTIME)//VM将在运行期也保留注释，因此可以通过反射机制读取注解的信息@Componentpublic @interface RpcService {    String value();}

HelloService.java

package com.mrbcy.bigdata.basic.spring.annotation;public interface HelloService {    String hello(String name);}

HelloServiceImpl.java

package com.mrbcy.bigdata.basic.spring.annotation;@RpcService("HelloServicebb")public class HelloServiceImpl implements HelloService {    public String hello(String name) {        return "Hello! " + name;    }    public void test(){        System.out.println("test");    }}

MyServer.java

package com.mrbcy.bigdata.basic.spring.annotation;import java.lang.reflect.Method;import java.util.Map;import org.springframework.beans.BeansException;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.context.ApplicationContext;import org.springframework.context.ApplicationContextAware;import org.springframework.context.support.ClassPathXmlApplicationContext;import org.springframework.stereotype.Component;@Component        //ApplicationContextAware会为Component组件调用setApplicationContext方法；  测试Myserver3时注释public class MyServer implements ApplicationContextAware {    public static void main(String[] args) {        ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext2.xml");    }    public void setApplicationContext(ApplicationContext ctx)            throws BeansException {        Map<String, Object> serviceBeanMap = ctx                .getBeansWithAnnotation(RpcService.class);        for (Object serviceBean : serviceBeanMap.values()) {            try {                //获取自定义注解上的value                String value = serviceBean.getClass().getAnnotation(RpcService.class).value();                System.out.println("注解上的value: " + value);                //反射被注解类，并调用指定方法                Method method = serviceBean.getClass().getMethod("hello",                        new Class[] { String.class });                Object invoke = method.invoke(serviceBean, "bbb");                System.out.println(invoke);            } catch (Exception e) {                e.printStackTrace();            }        }    }}

applicationContext2.xml

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"       xmlns:context="http://www.springframework.org/schema/context"       xsi:schemaLocation="http://www.springframework.org/schema/beans       http://www.springframework.org/schema/beans/spring-beans.xsd       http://www.springframework.org/schema/context       http://www.springframework.org/schema/context/spring-context.xsd">    <context:component-scan base-package="com.mrbcy.bigdata.basic.spring.annotation"/></beans>

执行结果：

注解上的value: HelloServicebbHello! bbb

可以看出Spring框架拿到了使用了我们自定义注解的类然后成功调用了它的成员函数。

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