java静态代理，动态代理（JDK,CGLib）

静态代理

Hello接口

public interface Hello {
    void say(String name);
}

Hello实现类

public class HelloImpl implements  Hello {
    public void say(String name) {
        System.out.println("Hello "+name);
    }
}

Hello代理类

public class HelloProxy implements  Hello {
    private Hello hello;
    public HelloProxy(){
        hello = new HelloImpl();
    }
    public void say(String name) {
        before();
        hello.say(name);
        after();
    }

    private void before(){
        System.out.println("before");
    }

    private void after(){
        System.out.println("after");
    }
}

测试类

public class Main {
    public static void main(String[] args) {
        Hello helloProxy = new HelloProxy();
        helloProxy.say("world");
    }
}

JDK动态代理

DynamicProxy 类

public class DynamicProxy implements InvocationHandler {
    private Object target;

    public DynamicProxy(Object target){
        this.target = target;
    }


    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        System.out.println("before");
        Object result = method.invoke(target,args);
        System.out.println("after");
        return result;
    }
}

测试类

public class main {
    public static void main(String[] args) {
        Hello hello = new HelloImpl();
        DynamicProxy dynamicProxy = new DynamicProxy(hello);
        Hello helloProxy = (Hello)Proxy.newProxyInstance(
                hello.getClass().getClassLoader(),
                hello.getClass().getInterfaces(),
                dynamicProxy
        );
        helloProxy.say("world");
    }
}

CGLib

CGLibProxy类

public class CGLibProxy implements MethodInterceptor{

    private static CGLibProxy instance = new CGLibProxy();

    private CGLibProxy(){
    }

    public static CGLibProxy getInstance(){
        return instance;
    }
    public <T> T getProxy(Class<T> cls){
        return (T) Enhancer.create(cls,this);
    }
    public Object intercept(Object o, Method method, Object[] objects, MethodProxy methodProxy) throws Throwable {
        System.out.println("before");
        Object result = methodProxy.invokeSuper(o,objects);
        System.out.println("after");
        return result;

    }
}

测试类

public class Main {
    public static void main(String[] args) {
        Hello helloProxy = CGLibProxy.getInstance().getProxy(HelloImpl.class);
        helloProxy.say("world");
    }
}