How to persist very 100 record from List

Question

MY list size is consist 5000 records i need to get 100 records every time from list then persist to 100 records each time up to 5000 records persist to DB how can achieve this logic?

private  List<DoTempCustomers> doTempCustomers;
for(DoTempCustomers tempCustomers:doTempCustomers){
try {
    temp=new TempCustomers();               
    BeanUtils.copyProperties(temp, doTemp);
    getEntityManager().persist(temp);
}

my above code i was persist all 5000 records single for each loop.

Answer 1

Try splitting the list into parts, and then do operations on each of sublists. If you need how to split list, you can refer this link: How to split array list into equal parts? which gives you idea.

Answer 2

You can use subList method of List to get the smaller view of the List

private  List<DoTempCustomers> doTempCustomers;
//initialize doTempCustomers list
List<String> muSubList = doTempCustomers.subList(0, 100);
//this will return a view of the specified range 
//(here from 0 to 99, 0 -inclusive and 100 - exclusive) within this list

Refer Javadoc for List#subList

Answer 3

I solved same problem before some days ago. my sample code to save 1000 record each time from list rather than 500 in your case.

    public void persistData(){

    int tempTblCount = tempTblCount();     // 5000 in your case
    int loopCount = tempTblCount / 1000 + 1;
    int limit = 1;

    while (loopCount > 0) {

       // here i get list of data from temp table having query limit;
       List<MyCustomerVO> myCustomerList = getListFromTempTblData(limit);

       for (iterate over your list) {
              persist your record here;
       }
    }

    limit = limit + 1000;
    loopCount--;

   }

    public List<MyCustomerVO> getListFromTempTblData(int limit) {

    List<MyCustomerVO> getTempTblData = null;
    String sql = " select mobile_number,customer_no from temp_tbl limit "+limit+" , 1000 ";
    execute query;
    return list;

    }