java 分批次读取java.util.List 数据

java 功能源代码：

 @RequestMapping({"/batchupdate"}) 
  @ResponseBody 
  public String batchUpdate(){ 
	  String result = ""; 
	  try{ 
	  List<Account> list = accountService.batchUpdate(); 
	  List<Account> batch = new ArrayList<Account>(); 
	   
	  
	  //密码修改 
	  if(list !=null && list.size()>0){ 
		  for(int i=0;i<list.size();i++){ 
			  Account account =list.get(i); 
			  String oldpassword = account.getPassword(); 
			  account.setPassword(EncryptUtils.encodeBase64String(oldpassword)); 
			  batch.add(account); 
		  } 
	  } 
	  //一次处理数据量 
	  int  init = 1000;// 每隔1000条循环一次  =1000; 
	  //总数 
	  int nums = batch.size(); 
	  //批次数 
	  int batchnum = nums / init;   
	  if (nums % init != 0) {   
		  batchnum += 1;   
          if (nums < init) {   
              init = list.size();   
          }   
      }  
	   
	   for (int i = 0; i < batchnum; i++) {   
           System.out.println("------" + i + "保存"+init+"条数据到数据库....");   
           List<Account> a = new ArrayList<Account>(); 
           if (i == batchnum - 1) {   
               int size = (i + 1) * init;   
               for (int j = size - init; j < nums; j++) {   
            	   if (batch.get(j) == null) {   
                       break;   
                   }  
            	   a.add(batch.get(j));   
               }   
               
           } else {   
               int size = (i + 1) * init;   
               for (int j = size - init; j < size; j++) {  
            	   if (batch.get(j) == null) {   
                       break;   
                   }   
            	   a.add(batch.get(j));   
               }   
              
           }   
           accountService.updateBatch(a); 
           
       }   
	   
	  
	 
	   
	  }catch(Exception e){ 
		  System.out.println(e.getMessage()); 
		  return "false"; 
	  } 
	  result = "true"; 
	  return result; 
	   
  }

待补充