动态代理

自定义2个接口subject1,subject2

package proxy;

public interface Subject1 {
    public void doSomething();
}



package proxy;

public interface Subject2 {
    public void doOtherthing();
}

定义2个真实的RealSubject1(implements subject1),RealSubject2(implements subject1,subject2)

package proxy;

public class RealSubject1 implements Subject1 {

    @Override
    public void doSomething() {
        // TODO Auto-generated method stub
        System.out.println("realSubject1 invoke from Subject1");
    }

}

package proxy;

public class RealSubject2 implements Subject2,Subject1{

    @Override
    public void doOtherthing() {
        System.out.println("realSubject2 invoke from Subject2");
        
    }
    @Override
    public void doSomething() {
        System.out.println("realSubject2 invoke from Subject1");

    }

}

创建一个invocationHandler

package proxy;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;

public class DynanicSubject implements InvocationHandler {
    private Object o1;
    public DynanicSubject(Object obj){
        this.o1=obj;
    }
    @Override
    public Object invoke(Object proxy, Method method, Object[] args)
            throws Throwable {
        System.out.println("执行前");
        method.invoke(o1, args);
        System.out.println("执行后");
        return null;
    }

}

创建测试类

package proxy;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Proxy;

public class Client {
    public static void main(String[] args) {
               //分别创建真实类对象以及handler
        Subject1 sub1=new RealSubject1();
        RealSubject2 sub2=new RealSubject2();
                 
        InvocationHandler hander=new DynanicSubject(sub1);
        InvocationHandler hander2=new DynanicSubject(sub2);
                 //创建动态代理类 （由于RealSubject2实现2个接口，因此下面进行2此转换，分别调用2个方法）
        Subject1 su=(Subject1)Proxy.newProxyInstance(hander.getClass().getClassLoader(), sub1.getClass().getInterfaces(), hander);
        Subject2 su2=(Subject2)Proxy.newProxyInstance(hander2.getClass().getClassLoader(), sub2.getClass().getInterfaces(), hander2);
        su.doSomething();
        su2.doOtherthing();
        Subject1 su3=(Subject1)Proxy.newProxyInstance(hander2.getClass().getClassLoader(), sub2.getClass().getInterfaces(), hander2);
        su3.doSomething();
    }
}  

执行结果：

执行前
realSubject1 invoke from Subject1
执行后
执行前
realSubject2 invoke from Subject2
执行后
执行前
realSubject2 invoke from Subject1
执行后