JDK dynamic proxies and cglib dynamic proxies

Object java.lang.reflect.Proxy.newProxyInstance (ClassLoader loader, class<?>[] Interfaces,invocationhandler H ) throwsillegalargumentexception

Returns an instance of a proxy class for the specified interfaces which dispatches method invocations to the specified Cation handler

This means that the method returns a proxy class for the specified interface, which dispatches the method call to the specified invocation handle, the so-called invocation handler is the proxy.

It is clear that the classes in the JDK to be dynamically represented need to implement an interface.

public class Robotproxy implements Invocationhandler {

	private Object target;
	
	@Override Public
	object Invoke (Object proxy, Method method, object[] args)
			throws Throwable {
		SYSTEM.OUT.PRINTLN ("Robot proxy access");
		Object result = Method.invoke (target, args);
		SYSTEM.OUT.PRINTLN ("Robot proxy Leave");
		return result;
	}

	public object getinstance (object target) {
		this.target = target;
		Return Proxy.newproxyinstance (Target.getclass (). getClassLoader (), 
				Target.getclass (). Getinterfaces (), this);

}

Using agents

Robot Robot = new Robot ();
		
Robotproxy rproxy = new Robotproxy ();
Language IRobot = (Language) rproxy.getinstance (robot);
Irobot.spell ("Hello World, I name is a intelegent robot!");

This proxy returns the interface type

Robot IRobot = (Robot) rproxy.getinstance (Robot);

Change to the above code will be an error

Exception in thread "main" Java.lang.ClassCastException: $Proxy 0 cannot is cast to Robot
At Robottest.main (robottest.java:13)

Cglib is a dynamic proxy that is implemented by generating subclasses of classes, allowing the interface to be represented without implementation.

public class Robotcglibproxy implements Methodinterceptor {

	private Object target;
	
	public object getinstance (object target) {
		this.target = target;
		Enhancer enhancer = new enhancer ();
		Enhancer.setsuperclass (Target.getclass ());
		Enhancer.setcallback (this);
		return Enhancer.create ();
	}
	
	@Override public
	Object intercept (Object obj, Method method, object[] args,
			methodproxy proxy) throws Throwable {
		System.out.println ("Robot cglib proxy Access");
		Object result = Proxy.invoke (target, args);
		System.out.println ("Robot cglib proxy Leave");
		return result;
	}

To test the interface, I removed it.

public class Robot {public

	void spell (String words) {
		System.out.println (words);
	}
	
	Public String Getrobotname () {return
		' Timi ';
	}

}

Robot Robot = new Robot ();
Robotcglibproxy rcproxy = new Robotcglibproxy ();
Robot Icrobot = (Robot) rcproxy.getinstance (Robot);
Icrobot.spell ("Hello World, I name is a intelegent robot!");
System.out.println ("Robot name is:" +icrobot.getrobotname ());