hadoop29---自定义注解

Posted 2020-11-05 672530440

自定义注解：

package cn.itcast_04_springannotation.userdefinedannotation.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;
//自定义注解的规范

@Target({ ElementType.TYPE }) //表示@RpcService这个注解是用在类上的，METHOD表示注解用在方法上的。
@Retention(RetentionPolicy.RUNTIME) //注解的生命周期，VM将在运行期保留注解，spring会把这个注解标注的类做实例化。
@Component //让spring去扫描
public @interface RpcService {
    String value();//@RpcService("HelloServicebb")的HelloServicebb
}

service接口

package cn.itcast_04_springannotation.userdefinedannotation.service;


public interface HelloService {
    String hello(String name);
}

service实现：

package cn.itcast_04_springannotation.userdefinedannotation.service.impl;

import cn.itcast_04_springannotation.userdefinedannotation.annotation.RpcService;
import cn.itcast_04_springannotation.userdefinedannotation.service.HelloService;


@RpcService("HelloServicebb")
public class HelloServiceImpl implements HelloService {
    public String hello(String name) {
        return "Hello! " + name;
    }
    
    public void test(){
        System.out.println("test");
    }
}

测试：

package cn.itcast_04_springannotation.userdefinedannotation.test;

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;

import cn.itcast_04_springannotation.userdefinedannotation.annotation.RpcService;
import cn.itcast_04_springannotation.userdefinedannotation.service.HelloService;

@Component        //测试Myserver3时注释
public class MyServer implements ApplicationContextAware {
    //如果某个类实现了ApplicationContextAware接口，会在类初始化完成后调用setApplicationContext（）方法进行操作
    @SuppressWarnings("resource")
    public static void main(String[] args) {
        ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext("spring2.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">
               
               //扫描包，把自定义和不是自定义的注解都加进来
            <context:component-scan base-package="cn.itcast_04_springannotation.userdefinedannotation"/>
            
        </beans>*/
    }


    public void setApplicationContext(ApplicationContext ctx)
            throws BeansException {
        Map<String, Object> serviceBeanMap = ctx
                .getBeansWithAnnotation(RpcService.class);//拿到标注了自定义注解的对象
        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();
            }
        }
    }

}

测试2：

package cn.itcast_04_springannotation.userdefinedannotation.test;

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;

import cn.itcast_04_springannotation.userdefinedannotation.annotation.RpcService;
import cn.itcast_04_springannotation.userdefinedannotation.service.HelloService;

//@RunWith(SpringJUnit4ClassRunner.class)
//@ContextConfiguration(locations = "classpath:spring2.xml")
//@Component
public class MyServer2 implements ApplicationContextAware {
    @SuppressWarnings("resource")
    public static void main(String[] args) {
        ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext("spring2.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="cn.itcast_04_springannotation.userdefinedannotation"/>
            
        </beans>*/
    
        Map<String, Object> beans = ctx.getBeansWithAnnotation(RpcService.class);
        for(Object obj: beans.values()){
            HelloService hello=(HelloService) obj;
            String hello2 = hello.hello("mmmm");
            System.out.println(hello2);
        }
    }

    /*@Test
    public void helloTest1() {
    System.out.println("开始junit测试……");
    }*/

    public void setApplicationContext(ApplicationContext ctx)
            throws BeansException {
        Map<String, Object> serviceBeanMap = ctx
                .getBeansWithAnnotation(RpcService.class);
        for (Object serviceBean : serviceBeanMap.values()) {
            try {
                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();
            }
        }
    }

}

测试3：

package cn.itcast_04_springannotation.userdefinedannotation.test;

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

import cn.itcast_04_springannotation.userdefinedannotation.service.HelloService;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = "classpath:spring2.xml")
@Component
public class MyServer3 {
    @Autowired
    HelloService helloService;

    @Test
    public void helloTest1() {
        System.out.println("开始junit测试……");
        String hello = helloService.hello("ooooooo");
        System.out.println(hello);
    }

}