代码篇之代理

public class ProxyTest {

    public static void main(String[] args) throws Exception{
        Class clazzProxy1 = Proxy.getProxyClass(Collection.class.getClassLoader(), Collection.class);
        System.out.println(clazzProxy1.getName());
        
        System.out.println("----------begin constructors list----------");
        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----------");
        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----------");
        Constructor constructor = clazzProxy1.getConstructor(InvocationHandler.class);
        class MyInvocationHander1 implements InvocationHandler{
            public Object invoke(Object proxy, Method method, Object[] args)
                    throws Throwable {
                return null;
            }
        
        }
        Collection proxy1 = (Collection)constructor.newInstance(new MyInvocationHander1());
        
        System.out.println(proxy1);
        proxy1.clear();
        
        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;
    }

}

Advice类

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

MyAdvice类

public class MyAdvice implements Advice {
    long beginTime = 0;
    public void afterMethod(Method method) {
        // TODO Auto-generated method stub
        System.out.println("从传智播客毕业上班啦！");        
        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("到传智播客来学习啦！");
        beginTime = System.currentTimeMillis();
    }

}