Java动态代理

JDK动态代理

1.编写接口，提供对外需要被代理的方法
2.编写这个类的实现类，真实被代理的对象
3.编写一个InvocationHandler接口实现类，它里面定义了一个invoke方法调用代理对象时执行具体方法

接口

public interface IHello {
    void sayHello(String name);
}

接口实现类

public class HelloImpl implements IHello {

    @Override
    public void sayHello(String name) {
        System.out.println("hello "+name);
    }
}

InvocationHandler接口实现类

public class JdkProxy implements InvocationHandler {
    private Object target;

    
    public Object binding(Object target){
        this.target=target;
        return Proxy.newProxyInstance(target.getClass().getClassLoader(),target.getClass().getInterfaces(),this);
    }
    
    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        System.out.println("调用之前");
        Object res = method.invoke(target, args);
        System.out.println("调用之后");

        return res;
    }
}

测试

public class JProxyTest {
    public static void main(String[] args) {
        JdkProxy jdkProxy = new JdkProxy();
        IHello binding = (IHello) jdkProxy.binding(new HelloImpl());
        binding.sayHello("jdk");

    }
}

CGLIB动态代理

1.编写真实被代理的对象(类)
2.编写一个MethodInterceptor接口实现类，它里面定义了一个intercept方法调用代理对象时执行具体方法

被代理的对象(类)

public class Person {
    public void sayHello(String name) {
        System.out.println("Hello " + name);
    }
}

MethodInterceptor接口实现类

public class ProxyCglib implements MethodInterceptor {
    public Object getPorxy(Class t){
        Enhancer enhancer = new Enhancer();
        enhancer.setSuperclass(t);
        enhancer.setCallback(this);
        return enhancer.create();
    }
    @Override
    public Object intercept(Object o, Method method, Object[] objects, MethodProxy methodProxy) throws Throwable {
        System.out.println("调用对象之前");
        Object o = methodProxy.invokeSuper(o, objects);
        System.out.println("调用对象之后");
        return o;
    }
}

测试

public class TestDemo {
    public static void main(String[] args) {
        ProxyCglib proxyCglib = new ProxyCglib();
        Person porxy = (Person) proxyCglib.getPorxy(Person.class);
        porxy.sayHello("kkkk");
    }
}