java动态代理--代理接口无实现类

使用通过接口定义，或解析接口注解等完成相关功能，如mybatis的SqlSession.getMapper的实现

1.接口定义

package cn.proxy;

public interface IHello {
String say(String aa);
}


2.代理实现
package cn.proxy;

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

/**
* JDK动态代理代理类
*
*/
@SuppressWarnings("unchecked")
public class FacadeProxy implements InvocationHandler {
@Override
public Object invoke(Object proxy, Method method, Object[] args)
throws Throwable {
System.out.println("接口方法调用开始");
//执行方法
System.out.println("method toGenericString:"+method.toGenericString());
System.out.println("method name:"+method.getName());
System.out.println("method args:"+(String)args[0]);
System.out.println("接口方法调用结束");
return "调用返回值";
}

public static <T> T newMapperProxy(Class<T> mapperInterface) {
ClassLoader classLoader = mapperInterface.getClassLoader();
Class<?>[] interfaces = new Class[]{mapperInterface};
FacadeProxy proxy = new FacadeProxy();
return (T) Proxy.newProxyInstance(classLoader, interfaces, proxy);
}
}


4.运行
package cn.proxy;

public class Test {
public static void main(String[] args) {
IHello hello = FacadeProxy.newMapperProxy(IHello.class);
System.out.println(hello.say("hello world"));
}
}


运行结果：
接口方法调用开始
method toGenericString:public abstract java.lang.String cn.proxy.IHello.say(java.lang.String)
method name:say
method args:hello world
接口方法调用结束
调用返回值