关于BeanUtil.copyProperties性能

BeanUtil.copyProperties 方法确实很方便，代码写出来非常优美，不会有很多的get set,但由于用到反射，可能存在潜在的性能问题。因此对spring 和 commons的BeanUtil.copyProperties进行了对照测试，代码大致如下：

 @Test
     public   void  copyPropertiesTest()  throws  IllegalAccessException, InvocationTargetException {

         po = new  PromotionPO();
         Timestamp now = new  Timestamp(System.currentTimeMillis());
         model = RetailmodelFactory.eINSTANCE.createPromotion();
 //get/set
         Long startTime = System.currentTimeMillis();
         for  ( int  i =  0 ; i < LOOP_NUMBER; i++) {
             model.setCode("code" );
             model.setDescription("haha" );
             model.setDiscount(5.4 );
             model.setEndTime(now);
             model.setID(39578395L);
             model.setPriority(1 );
             model.setPromotionType(3 );
             model.setStartTime(now);
             model.setSupplierID("123245L" );
         }
         Long endTime = System.currentTimeMillis();
         traditionalCopyTIme = endTime - startTime;

 //spring
         startTime = System.currentTimeMillis();
         for  ( int  i =  0 ; i < LOOP_NUMBER; i++) {
             BeanUtils.copyProperties(model, po);
         }
         endTime = System.currentTimeMillis();
         springCopyPropertiesTime = endTime - startTime;

 //commons
         startTime = System.currentTimeMillis();
         for  ( int  i =  0 ; i < LOOP_NUMBER; i++) {
             org.apache.commons.beanutils.BeanUtils.copyProperties(po,model);
         }
         endTime = System.currentTimeMillis();
         commonsCopyPropertiesTime = endTime - startTime;

         logger.info("normal copy Time: "  +  traditionalCopyTIme +  "ms." );
         logger.info("Spring BeanUtil copy Time: "  +  springCopyPropertiesTime +  "ms." );
         logger.info("Commons BeanUtil copy Time: "  +  commonsCopyPropertiesTime +  "ms." );
     }

当 LOOP_NUMBER = 50000时（即执行50000次copy），结果如下：

编号	set/get	Spring BeanUtil	Commons BeanUtil
1	62ms	1703ms	63860ms
1	16ms	1359ms	62328ms
1	16ms	1359ms	63047ms
1	0ms	1390ms	63047ms
1	16ms	1375ms	62266ms

可看出Commons BeanUtil的copyProperties 性能最差，几乎不能忍受。spring的copyProperties有可能在接受范围内。直接set/get虽然丑陋，但是性能确实非常好，几乎可以忽略。
接下来对spring和commons两种不同实现进行分析。