java list remove duplicate values

One:

Hastset determines whether it is duplicated based on hashcode, and the data will not be repeated

Java code

/** List order not maintained **/ ashSet h = new HashSet (arlList);

arlList.clear();

arlList.addAll(h); Then do not add

Java code

/** List order maintained **/      
public static void removeDuplicateWithOrder(ArrayList arlList)      
{      
Set set = new HashSet();      
List newList = new ArrayList();      
for (Iterator iter = arlList.iterator(); iter.hasNext(); )      
{      
Object element = iter.next();      
if (set.add(element)) newList.add(element);      
}      
arlList.clear();      
arlList.addAll(newList);      
}

The following comes from the Internet:

Method 1: Loop element deletion

//  删除ArrayList中重复元素 
 public   static   void  removeDuplicate(List list)  {
   for  ( int  i  =   0 ; i  <  list.size()  -   1 ; i ++ )  {
    for  ( int  j  =  list.size()  -   1 ; j  >  i; j -- )  {
      if  (list.get(j).equals(list.get(i)))  {
        list.remove(j);
      } 
    } 
  } 
  System.out.println(list);
}

Method 2: Eliminate through HashSet

//  删除ArrayList中重复元素 
 public   static   void  removeDuplicate(List list)  {
    HashSet h  =   new  HashSet(list);
    list.clear();
    list.addAll(h);
    System.out.println(list);
}

Method 3: Delete duplicate elements in ArrayList and maintain order

// 删除ArrayList中重复元素，保持顺序 
 public   static   void  removeDuplicateWithOrder(List list)  {
      Set set  =   new  HashSet();
      List newList  =   new  ArrayList();
   for  (Iterator iter  =  list.iterator(); iter.hasNext();)  {
         Object element  =  iter.next();
         if  (set.add(element))
            newList.add(element);
     } 
     list.clear();
     list.addAll(newList);
     System.out.println( " remove duplicate "   +  list);
 }
 
自己使用： 删除 “0.0”的值
List<List<String>> list1 = (List<List<String>>) map.get("商品入库表"); //表1 入库详细表


//删除list中 数量为 0值
for (Iterator<List<String>> item = list1.iterator(); item.hasNext(); ) {
    List<String> it = item.next();
    System.out.print(it);
    if (it.get(4).equals("0.0")) {
        item.remove();
    }
}

Link address: http://iteye.blog.163.com/blog/static/186308096201302565345510/