使用JDK支持的代理模式, 动态代理
场景如下: 本文例子代理了ArrayList, 在ArrayList每次操作时, 在操作之前和之后都进行一些额外的操作.
这里是代理的实现.
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
public class ArrayListProxy implements InvocationHandler {
private Object proxy;
public ArrayListProxy(Object obj) {
this.proxy = obj;
}
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Exception {
System.out.println("before calling " + method);
if (args != null) {
for (Object arg : args) {
System.out.println(arg);
}
}
Object o = method.invoke(this.proxy, args);
System.out.println("after calling " + method);
return o;
}
}
封装了Proxy.newProxyInstance()方法, 方便取得代理对象.
import java.lang.reflect.Proxy;
public class MyUtils {
public static Object getProxy(Object obj) {
Class cls = obj.getClass();
return Proxy.newProxyInstance(
cls.getClassLoader(),
cls.getInterfaces(),
new ArrayListProxy(obj)
);
}
}
在这里进行运行测试
import java.util.ArrayList;
import java.util.List;
@SuppressWarnings("unchecked")
public class Main {
public static void main(String[] args) {
List realList = new ArrayList<String>(10);
List proxyList = (List) MyUtils.getProxy(realList);
proxyList.add("New");
System.out.print("\n\n");
proxyList.add("York");
}
}
原文：https://www.cnblogs.com/noKing/p/9063811.html