java中的代理

package cn.itcast.day3;

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.ArrayList;
import java.util.Collection;

public class ProxyTest {

/**
* @param args
*/
public static void main(String[] args) throws Exception {
// TODO Auto-generated method stub
Class clazzProxy1 = Proxy.getProxyClass(Collection.class.getClassLoader(), Collection.class);
System.out.println(clazzProxy1.getName());

System.out.println("----------begin constructors list----------");
/*
* $Proxy0() $Proxy0(InvocationHandler,int)
*/
Constructor[] constructors = clazzProxy1.getConstructors();
for (Constructor constructor : constructors) {
String name = constructor.getName();
StringBuilder sBuilder = new StringBuilder(name);
sBuilder.append('(');
Class[] clazzParams = constructor.getParameterTypes();
for (Class clazzParam : clazzParams) {
sBuilder.append(clazzParam.getName()).append(',');
}
if (clazzParams != null && clazzParams.length != 0)
sBuilder.deleteCharAt(sBuilder.length() - 1);
sBuilder.append(')');
System.out.println(sBuilder.toString());
}

System.out.println("----------begin methods list----------");
/*
* $Proxy0() $Proxy0(InvocationHandler,int)
*/
Method[] methods = clazzProxy1.getMethods();
for (Method method : methods) {
String name = method.getName();
StringBuilder sBuilder = new StringBuilder(name);
sBuilder.append('(');
Class[] clazzParams = method.getParameterTypes();
for (Class clazzParam : clazzParams) {
sBuilder.append(clazzParam.getName()).append(',');
}
if (clazzParams != null && clazzParams.length != 0)
sBuilder.deleteCharAt(sBuilder.length() - 1);
sBuilder.append(')');
System.out.println(sBuilder.toString());
}

System.out.println("----------begin create instance object----------");
// Object obj = clazzProxy1.newInstance();
Constructor constructor = clazzProxy1.getConstructor(InvocationHandler.class);
class MyInvocationHander1 implements InvocationHandler {

public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
// TODO Auto-generated method stub
return null;
}

}
Collection proxy1 = (Collection) constructor.newInstance(new MyInvocationHander1());

System.out.println(proxy1);
proxy1.clear();
// proxy1.size();
// System.out.println("111111111111111");

Collection proxy2 = (Collection) constructor.newInstance(new InvocationHandler() {

public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
return null;
}

});

final ArrayList target = new ArrayList();
Collection proxy3 = (Collection) getProxy(target, new MyAdvice());
proxy3.add("zxx");
proxy3.add("lhm");
proxy3.add("bxd");
System.out.println(proxy3.size());
System.out.println(proxy3.getClass().getName());
}

private static Object getProxy(final Object target, final Advice advice) {
Object proxy3 = Proxy.newProxyInstance(target.getClass().getClassLoader(),
/* new Class[]{Collection.class}, */
target.getClass().getInterfaces(), new InvocationHandler() {

public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {

/*
* long beginTime = System.currentTimeMillis(); Object retVal =
* method.invoke(target, args); long endTime =
* System.currentTimeMillis();
* System.out.println(method.getName() + " running time of " +
* (endTime - beginTime)); return retVal;
*/

advice.beforeMethod(method);
Object retVal = method.invoke(target, args);
advice.afterMethod(method);
return retVal;

}
});
return proxy3;
}

}

----------------------------------------------------------------------------

package cn.itcast.day3;

import java.lang.reflect.Method;

public interface Advice {
void beforeMethod(Method method);
void afterMethod(Method method);
}
----------------------------------------------------------

package cn.itcast.day3;

import java.lang.reflect.Method;

public class MyAdvice implements Advice {
long beginTime = 0;

public void afterMethod(Method method) {
// TODO Auto-generated method stub
System.out.println("调用方法后做的事！");
long endTime = System.currentTimeMillis();
System.out.println(method.getName() + " running time of " + (endTime - beginTime));

}

public void beforeMethod(Method method) {
// TODO Auto-generated method stub
System.out.println("调用方法前做的事！");
beginTime = System.currentTimeMillis();
}

}