转:注解+动态代理例子

在公司没事干了，学习下动态代理模式（关于代理的基础只是有很多帖子都有我就不重复了），做了个注解动态代理的例子，给那些学习注解或动态代理的初学者。

花了将近1小时，没做个什么优化，大牛勿喷。

几个主要的类：

注解类：

package test2;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;


@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface ProxyTag {
    public Class proxyClass();
}

package test2;



import java.lang.annotation.ElementType;

import java.lang.annotation.Retention;

import java.lang.annotation.RetentionPolicy;

import java.lang.annotation.Target;





@Retention(RetentionPolicy.RUNTIME) 

@Target(ElementType.METHOD)

public @interface ProxyTag {

	public Class proxyClass();

}

 

代理类父类：

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

public abstract class  ProxyBean implements InvocationHandler{

    private Object o;


    private String methodName;

    public Object bind(Object obj,String methodName){
        this.o = obj;
        return Proxy.newProxyInstance(obj.getClass().getClassLoader(), obj.getClass().getInterfaces(), this);
    }


    public Object invoke(Object proxy, Method method, Object[] obj)
            throws Throwable {
        if(method.getName().equals(methodName)){
            this.before();
            Object result = method.invoke(o, obj);
            this.after();
            return result;
        }else{
            Object result = method.invoke(o, obj);
            return result;
        }

    }

    public abstract void before();

    public abstract void after();
}

import java.lang.reflect.InvocationHandler;

import java.lang.reflect.Method;

import java.lang.reflect.Proxy;



public abstract class  ProxyBean implements InvocationHandler{

	

	private Object o;



	

	private String methodName;

	

	public Object bind(Object obj,String methodName){

		this.o = obj;

		return Proxy.newProxyInstance(obj.getClass().getClassLoader(), obj.getClass().getInterfaces(), this);

	}

	

	

	public Object invoke(Object proxy, Method method, Object[] obj)

			throws Throwable {

		if(method.getName().equals(methodName)){

			this.before();

			Object result = method.invoke(o, obj);

			this.after();

			return result;

		}else{

			Object result = method.invoke(o, obj);

			return result;

		}

		

	}

	

	public abstract void before();

	

	public abstract void after();

}

代理工厂：

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

public class ProxyFactory {


    public static <T> T getProxyBean(Class<T> clazz){
        T t = (T) newInstance(clazz);
        Method[] methods = clazz.getMethods();

        for(int i=0;i<methods.length;i++){
            ProxyTag pt = methods[i].getAnnotation(ProxyTag.class);
            if(pt == null){
                continue;
            }
            ProxyBean pb = (ProxyBean) newInstance(pt.proxyClass());
            t = (T) pb.bind(t, methods[i].getName());
        }
        return t;
    }

    private static Object newInstance(final Class clazz){
        try {
            Constructor cons = clazz.getConstructor();
            return cons.newInstance(new Class[]{});
        } catch (SecurityException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (NoSuchMethodException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IllegalArgumentException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (InstantiationException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return null;
    }
}

import java.lang.reflect.Constructor;

import java.lang.reflect.InvocationTargetException;

import java.lang.reflect.Method;



public class ProxyFactory {

	

	

	public static <T> T getProxyBean(Class<T> clazz){

		T t = (T) newInstance(clazz);

		Method[] methods = clazz.getMethods();

		

		for(int i=0;i<methods.length;i++){

			ProxyTag pt = methods[i].getAnnotation(ProxyTag.class);

			if(pt == null){

				continue;

			}

			ProxyBean pb = (ProxyBean) newInstance(pt.proxyClass());

			t = (T) pb.bind(t, methods[i].getName());

		}

		return t;

	}

	

	private static Object newInstance(final Class clazz){

		try {

			Constructor cons = clazz.getConstructor();

			return cons.newInstance(new Class[]{});

		} catch (SecurityException e) {

			// TODO Auto-generated catch block

			e.printStackTrace();

		} catch (NoSuchMethodException e) {

			// TODO Auto-generated catch block

			e.printStackTrace();

		} catch (IllegalArgumentException e) {

			// TODO Auto-generated catch block

			e.printStackTrace();

		} catch (InstantiationException e) {

			// TODO Auto-generated catch block

			e.printStackTrace();

		} catch (IllegalAccessException e) {

			// TODO Auto-generated catch block

			e.printStackTrace();

		} catch (InvocationTargetException e) {

			// TODO Auto-generated catch block

			e.printStackTrace();

		}

		return null;

	}

}

 测试类：

package test2;

public class ProxyClass extends ProxyBean{

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

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

package test2;



public class ProxyClass extends ProxyBean{



	public void after() {

		System.out.println("after....");

	}



	public void before() {

		System.out.println("before....");

	}

}

public class ProxyClass2 extends ProxyBean{

    public void after() {
        System.out.println("after2....");
    }

    public void before() {
        System.out.println("before2....");
    }
}

public class ProxyClass2 extends ProxyBean{



	public void after() {

		System.out.println("after2....");

	}



	public void before() {

		System.out.println("before2....");

	}

}

 

public interface IDemo {
    public void sayHello();
    public void sayHello2();
}

public interface IDemo {

	public void sayHello();

	public void sayHello2();

}

 

public class Demo implements IDemo{

    @ProxyTag(proxyClass=ProxyClass.class)
    public void sayHello(){
        System.out.println("hello....");
    }

    @ProxyTag(proxyClass=ProxyClass2.class)
    public void sayHello2(){
        System.out.println("hello2....");
    }
}

public class Demo implements IDemo{

	

	@ProxyTag(proxyClass=ProxyClass.class)

	public void sayHello(){

		System.out.println("hello....");

	}

	

	@ProxyTag(proxyClass=ProxyClass2.class)

	public void sayHello2(){

		System.out.println("hello2....");

	}

}

public class Test {

    /**
     * @param args
     */
    public static void main(String[] args) {

        IDemo demo = ProxyFactory.getProxyBean(Demo.class);
        demo.sayHello();
        System.out.println("-----------------------------");
        demo.sayHello2();

    }

}

public class Test {



	/**

	 * @param args

	 */

	public static void main(String[] args) {

		

		IDemo demo = ProxyFactory.getProxyBean(Demo.class);

		demo.sayHello();

		System.out.println("-----------------------------");

		demo.sayHello2();



	}



}

before....
hello....
after....
-----------------------------
before2....
hello2....
after2....