How does proxy do in CGLIB?

package com.cglib; 

/** 
* Those are some base operation demo. 
*    
* @author daniel    cqyd505@gmail.com 
* @since 2010-07-08 11:25 
* 
*/ 
public class BaseOperations { 

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

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

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

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

/** 
*    
*/ 
package com.cglib; 

import java.lang.reflect.Method; 

import net.sf.cglib.proxy.MethodInterceptor; 
import net.sf.cglib.proxy.MethodProxy; 

/** 
* Method interceptor, as you see, this is a Interceptor, which can do some job before you call some method, 
* and the key is which can be used in call back by cglib, it's real cool! 
*    
* @author daniel    cqyd505@gmail.com 
* @since 2010-07-09 09:23 
* 
*/ 
public class MyMethodInterceptor implements MethodInterceptor{ 
    
  private String name; 

  public String getName() { 
    return name; 
  } 

  public void setName(String name) { 
    this.name = name; 
  } 

  public MyMethodInterceptor(String name) { 
    this.name = name; 
  } 

  /** 
    * Here we will set our interceptor for some method. 
    * As you see the interceptor is just for daniel by name. 
    */ 
  @Override 
  public Object intercept(Object arg0, Method arg1, Object[] arg2, 
      MethodProxy arg3) throws Throwable { 
    //interceptor 
    if (this.name.equals("daniel")) { 
      return arg3.invokeSuper(arg0, arg2); 
    }else{ 
      System.out.println("Method interceptor say: haha, just daniel can do delete! you are have no permits to do this operation!"); 
                        return null; 
    } 
  } 

} 

package com.cglib; 

import java.lang.reflect.Method; 

import net.sf.cglib.proxy.CallbackFilter; 

/** 
* Interceptro filter, which mean this is a filter for interceptor, in other words, when app use the interceptor, filter 
* will be called first, so it's can use for abstract the logic or bussiness into the filter, mean while you can    
* set many interceptor and not case it use or not, the "CallBackFilter" will charge it, you just need to foucs 
* at what will you do in filter.    
*    
* @author daniel    cqyd505@gmail.com 
* @since 2010-07-09 10:30 
* 
*/ 
public class InterceptorFilter implements CallbackFilter{ 

  private String operationName; 
    
  @Override 
  public int accept(Method arg0) { 
    /* 
     * The accept logic 
     */ 
    if(arg0.getName().toString().equals(this.operationName)){ 
      /* 
        * if the method name is equals to the filter's , call the No:0 interceptor 
        */ 
      return 0; 
    }else{ 
      /* 
        * call No:1 interceptor 
        */ 
      return 1; 
    } 
  } 

  public InterceptorFilter(String name) { 
    this.operationName = name; 
  } 
    
} 

package com.cglib; 

import net.sf.cglib.proxy.Callback; 
import net.sf.cglib.proxy.Enhancer; 
import net.sf.cglib.proxy.NoOp; 

/** 
* This factory can set some interceptors into the callback of the class, not interface. 
*    
* @author daniel    cqyd505@gmail.com 
* @since 2010-07-09 09:25 
* 
*/ 
public class InterceptorFactory { 

  /** 
    * Here we will set the callback process by cglib's net.sf.cglib.proxy.Enhancer. 
    *    
    * @param interceptor 
    * @return BaseOperations 
    * @see net.sf.cglib.proxy.Enhancer 
    */ 
  public static BaseOperations getBtsOperationInstanceWithInterceptor(MyMethodInterceptor interceptor) { 
    /* 
     * This is a often and regular using of Enhancer. 
     */ 
    Enhancer enhancer = new Enhancer(); 
    enhancer.setSuperclass(BaseOperations.class); 
    /* 
     * setCallback just one interceptor 
     */ 
    enhancer.setCallback(interceptor); 
    /* 
     * set two interceptors into callback, which will used will see the filter's logic 
     */ 
    Callback[] backs =    new Callback[]{interceptor,NoOp.INSTANCE};     
    enhancer.setCallbacks(backs); 
    //set filter 
    enhancer.setCallbackFilter(new InterceptorFilter("delete")); 
    BaseOperations baseOpt = (BaseOperations) enhancer.create(); 
                return baseOpt; 
        } 
    
  /** 
    * Pay attention: 
    *         Enhancer.setCallback and setCallbacks, by check the enhancer's source codethe, we find the setCallback 
    * will call setCallbacks() to set the same "Callback[]", so if you use the setCallBack before setCallBacks    
    * in reslut, the Callback[] will fit to the last one. 
    *         Which Means, at here, ehancer have two interceptor in callback, not three!    
    */ 
    
} 

/** 
*    
*/ 
package com.cglib; 

/** 
* In this case, we will do the job by cglib, we have set some method interceptor for our operations, let's take a look! 
*    
* @author daniel    cqyd505@gmail.com 
* @since 2010-07-09 09:37 
* 
*/ 
public  class CallInCase2 { 

   public  static  void main(String[] args) { 
    CallInCase2 c =  new CallInCase2(); 
                c.doOperation(); 
        } 

   /** 
    * Do the base operations. 
    */ 
   private  void doOperation() { 
    System.out.println( "app run:"); 
    System.out.println( "============================ console outting: ========================="); 
     //0.Create the interceptor 
    MyMethodInterceptor interceptor =     new MyMethodInterceptor( "Tom");  //not ok 
     //1.Get handler by factory 
    BaseOperations basOptHandler = InterceptorFactory.getBtsOperationInstanceWithInterceptor(interceptor); 
     //2.Try do job 
    basOptHandler.create(); 
    basOptHandler.query(); 
    basOptHandler.update(); 
    basOptHandler.delete(); 
     //3.say BYEBYE 
    System.out.println( "============================ app stop ========================="); 
  } 
    
} 

     本文转自danni505 51CTO博客，原文链接：http://blog.51cto.com/danni505/346758 ，如需转载请自行联系原作者