zoukankan      html  css  js  c++  java

  • 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：

    Java代码  收藏代码
    1. package test2;  
    2.   
    3. import java.lang.annotation.ElementType;  
    4. import java.lang.annotation.Retention;  
    5. import java.lang.annotation.RetentionPolicy;  
    6. import java.lang.annotation.Target;  
    7.   
    8.   
    9. @Retention(RetentionPolicy.RUNTIME)   
    10. @Target(ElementType.METHOD)  
    11. public @interface ProxyTag {  
    12.     public Class proxyClass();  
    13. }  
    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：

    Java代码  收藏代码
    1. import java.lang.reflect.InvocationHandler;  
    2. import java.lang.reflect.Method;  
    3. import java.lang.reflect.Proxy;  
    4.   
    5. public abstract class  ProxyBean implements InvocationHandler{  
    6.       
    7.     private Object o;  
    8.   
    9.       
    10.     private String methodName;  
    11.       
    12.     public Object bind(Object obj,String methodName){  
    13.         this.o = obj;  
    14.         return Proxy.newProxyInstance(obj.getClass().getClassLoader(), obj.getClass().getInterfaces(), this);  
    15.     }  
    16.       
    17.       
    18.     public Object invoke(Object proxy, Method method, Object[] obj)  
    19.             throws Throwable {  
    20.         if(method.getName().equals(methodName)){  
    21.             this.before();  
    22.             Object result = method.invoke(o, obj);  
    23.             this.after();  
    24.             return result;  
    25.         }else{  
    26.             Object result = method.invoke(o, obj);  
    27.             return result;  
    28.         }  
    29.           
    30.     }  
    31.       
    32.     public abstract void before();  
    33.       
    34.     public abstract void after();  
    35. }  
    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：

    Java代码  收藏代码
    1. import java.lang.reflect.Constructor;  
    2. import java.lang.reflect.InvocationTargetException;  
    3. import java.lang.reflect.Method;  
    4.   
    5. public class ProxyFactory {  
    6.       
    7.       
    8.     public static <T> T getProxyBean(Class<T> clazz){  
    9.         T t = (T) newInstance(clazz);  
    10.         Method[] methods = clazz.getMethods();  
    11.           
    12.         for(int i=0;i<methods.length;i++){  
    13.             ProxyTag pt = methods[i].getAnnotation(ProxyTag.class);  
    14.             if(pt == null){  
    15.                 continue;  
    16.             }  
    17.             ProxyBean pb = (ProxyBean) newInstance(pt.proxyClass());  
    18.             t = (T) pb.bind(t, methods[i].getName());  
    19.         }  
    20.         return t;  
    21.     }  
    22.       
    23.     private static Object newInstance(final Class clazz){  
    24.         try {  
    25.             Constructor cons = clazz.getConstructor();  
    26.             return cons.newInstance(new Class[]{});  
    27.         } catch (SecurityException e) {  
    28.             // TODO Auto-generated catch block  
    29.             e.printStackTrace();  
    30.         } catch (NoSuchMethodException e) {  
    31.             // TODO Auto-generated catch block  
    32.             e.printStackTrace();  
    33.         } catch (IllegalArgumentException e) {  
    34.             // TODO Auto-generated catch block  
    35.             e.printStackTrace();  
    36.         } catch (InstantiationException e) {  
    37.             // TODO Auto-generated catch block  
    38.             e.printStackTrace();  
    39.         } catch (IllegalAccessException e) {  
    40.             // TODO Auto-generated catch block  
    41.             e.printStackTrace();  
    42.         } catch (InvocationTargetException e) {  
    43.             // TODO Auto-generated catch block  
    44.             e.printStackTrace();  
    45.         }  
    46.         return null;  
    47.     }  
    48. }  
    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：

    Java代码  收藏代码
    1. package test2;  
    2.   
    3. public class ProxyClass extends ProxyBean{  
    4.   
    5.     public void after() {  
    6.         System.out.println("after....");  
    7.     }  
    8.   
    9.     public void before() {  
    10.         System.out.println("before....");  
    11.     }  
    12. }  
    package test2;

public class ProxyClass extends ProxyBean{

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

	public void before() {
		System.out.println("before....");
	}
}
    Java代码  收藏代码
    1. public class ProxyClass2 extends ProxyBean{  
    2.   
    3.     public void after() {  
    4.         System.out.println("after2....");  
    5.     }  
    6.   
    7.     public void before() {  
    8.         System.out.println("before2....");  
    9.     }  
    10. }  
    public class ProxyClass2 extends ProxyBean{

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

	public void before() {
		System.out.println("before2....");
	}
}
     
    Java代码  收藏代码
    1. public interface IDemo {  
    2.     public void sayHello();  
    3.     public void sayHello2();  
    4. }  
    public interface IDemo {
	public void sayHello();
	public void sayHello2();
}
     
    Java代码  收藏代码
    1. public class Demo implements IDemo{  
    2.       
    3.     @ProxyTag(proxyClass=ProxyClass.class)  
    4.     public void sayHello(){  
    5.         System.out.println("hello....");  
    6.     }  
    7.       
    8.     @ProxyTag(proxyClass=ProxyClass2.class)  
    9.     public void sayHello2(){  
    10.         System.out.println("hello2....");  
    11.     }  
    12. }  
    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....");
	}
}
    Java代码  收藏代码
    1. public class Test {  
    2.   
    3.     /** 
    4.      * @param args 
    5.      */  
    6.     public static void main(String[] args) {  
    7.           
    8.         IDemo demo = ProxyFactory.getProxyBean(Demo.class);  
    9.         demo.sayHello();  
    10.         System.out.println("-----------------------------");  
    11.         demo.sayHello2();  
    12.   
    13.     }  
    14.   
    15. }  
    public class Test {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		
		IDemo demo = ProxyFactory.getProxyBean(Demo.class);
		demo.sayHello();
		System.out.println("-----------------------------");
		demo.sayHello2();

	}

}
    Java代码  收藏代码
    1. before....  
    2. hello....  
    3. after....  
    4. -----------------------------  
    5. before2....  
    6. hello2....  
    7. after2.... 
  • 相关阅读:
    Yantai
    Star War
    douban's woshang
    cannot change font's type in coreldraw
    LuXun said
    WaiTan
    free ubuntu disk前天就收到了寄来的光盘
    Winter Swimming
    before buy laptop买本本前,先来看看
    ubuntu beginer
  • 原文地址：https://www.cnblogs.com/phoebus0501/p/1987552.html
Copyright © 2011-2022 走看看