java代理模式的实现方法

package com.sample.sping_ireport.cglib;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.Calendar;
import java.util.GregorianCalendar;

public class ProxyTest {
    public static void main(String[] args) {
        InvocationHandler handler = null;//调用代理
        AbstractUserDao userDao = new UserDao();//DAO
        handler = new DaoLogHandler(userDao);
        AbstractUserDao proxy = null;
        //动态创建代理对象，用于代理一个AbstarctUserDao类型的真实主题对象
        proxy = (AbstractUserDao) Proxy.newProxyInstance(AbstractUserDao.class.getClassLoader(), new Class[]{AbstractUserDao.class}, handler);
        proxy.findUserById("张无忌");
        
        System.out.println("------------------------");
        
        AbstractDocumentDao docDAO = new DocumentDao();  
        handler = new DaoLogHandler(docDAO);  
        AbstractDocumentDao proxy_new = null;  
        //动态创建代理对象，用于代理一个AbstractDocumentDAO类型的真实主题对象  
        proxy_new = (AbstractDocumentDao)Proxy.newProxyInstance(AbstractDocumentDao.class.getClassLoader(), new Class[]{AbstractDocumentDao.class}, handler);  
        proxy_new.deleteDocumentById("D001"); //调用代理对象的业务方法  
    }
}
interface AbstractUserDao{
    public Boolean findUserById(String userId);
}
interface AbstractDocumentDao{
    public Boolean deleteDocumentById(String documentId);
}
class UserDao implements AbstractUserDao{
    @Override
    public Boolean findUserById(String userId) {
        if(userId.equalsIgnoreCase("张无忌")){
            System.out.println("查询ID为"+userId+"的信息成功");
            return true;
        }else{
            System.out.println("查询ID为"+userId+"的信息失败");
            return false;
        }
    }
}
class DocumentDao implements AbstractDocumentDao{
    @Override
    public Boolean deleteDocumentById(String documentId) {
        if(documentId.equalsIgnoreCase("D001")){
            System.out.println("删除ID为"+documentId+"的文档成功");
            return true;
        }else{
            System.out.println("查询ID为"+documentId+"的文档失败");
            return false;
        }
    }
}
//自定义请求处理类,用于实现代理
class DaoLogHandler implements InvocationHandler{
    private Calendar calendar;
    private Object object;
    //带参和无参构造
    public DaoLogHandler(){
    }
    public DaoLogHandler(Object object){
        this.object = object;
    }
    
    @Override
    public Object invoke(Object proxy, Method method, Object[] args)throws Throwable {
        beforeInvoke();
        Object result = method.invoke(object, args);
        afterInvoke();
        return result;
    }
    //调用之后
    private void afterInvoke() {
        calendar = new GregorianCalendar();
        int hour = calendar.get(Calendar.HOUR_OF_DAY);
        int minute = calendar.get(Calendar.MINUTE);
        int second = calendar.get(Calendar.SECOND);
        int millSecond = calendar.get(Calendar.MILLISECOND);
        String time = hour + ":" +minute +":" +second +":" +millSecond;
        System.out.println("调用结束时间"+time);
    }
    //在调用之前
    public void beforeInvoke() {
        calendar = new GregorianCalendar();
        int hour = calendar.get(Calendar.HOUR_OF_DAY);
        int minute = calendar.get(Calendar.MINUTE);
        int second = calendar.get(Calendar.SECOND);
        int millSecond = calendar.get(Calendar.MILLISECOND);
        String time = hour + ":" +minute +":" +second+":" +millSecond;
        System.out.println("调用开始时间"+time);
    }
    
}
-----------------------------------
代码执行结果：
调用开始时间10:38:2:902
查询ID为张无忌的信息成功
调用结束时间10:38:2:903
------------------------
调用开始时间10:38:2:904
删除ID为D001的文档成功
调用结束时间10:38:2:905