JAVA动态代理实例

1.被动态代理类需要实现一个接口

public interface Subject {

    void request();
}

2.创建被动态代理类

public class RealSubject implements Subject{
    @Override
    public void request() {
        System.out.println("real subject");
    }
}

3.创建动态代理类

public class DynamicSubject implements InvocationHandler {

    private Object sub;

    public DynamicSubject(Object obj){
        this.sub = obj;
    }

    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        System.out.println("before");

        method.invoke(this.sub, args);

        System.out.println("end");
        return null;
    }
}

4.使用动态代理

public class Client {

    public static void main(String[] args){
        RealSubject rs = new RealSubject();
        InvocationHandler ds = new DynamicSubject(rs);
        Class<?> cls = rs.getClass();

        Subject subject = (Subject) Proxy.
                newProxyInstance(cls.getClassLoader(), cls.getInterfaces(), ds);

        subject.request();

        System.out.println(subject.getClass());
        //class com.sun.proxy.$Proxy0
        System.out.println(subject.getClass().getSuperclass());
        //class java.lang.reflect.Proxy
    }
}

5.控制台打印效果

before
real subject
end
class com.sun.proxy.$Proxy0
class java.lang.reflect.Proxy