JAVA实现数据等分将一个List分成多个List

1.将一组数据固定分组，每组n个元素：

public static  List> split(List resList, int subListLength) {
   if (CollectionUtils.isEmpty(resList) || subListLength <= 0) {
      return Lists.newArrayList();
   }
   List> ret = Lists.newArrayList();
   int size = resList.size();
   if (size <= subListLength) {
      // 数据量不足 subListLength 指定的大小
      ret.add(resList);
   } else {
      int pre = size / subListLength;
      int last = size % subListLength;
      // 前面pre个集合，每个大小都是 subListLength 个元素
      for (int i = 0; i < pre; i++) {
         List itemList = Lists.newArrayList();
         for (int j = 0; j < subListLength; j++) {
            itemList.add(resList.get(i * subListLength + j));
         }
         ret.add(itemList);
      }
      // last的进行处理
      if (last > 0) {
         List itemList = Lists.newArrayList();
         for (int i = 0; i < last; i++) {
            itemList.add(resList.get(pre * subListLength + i));
         }
         ret.add(itemList);
      }
   }
   return ret;
}

2.将一组数据平均分成n组：

public static  List> averageAssign(List source, int n) {
   List> result = new ArrayList>();
   int remainder = source.size() % n;  //(先计算出余数)
   int number = source.size() / n;  //然后是商
   int offset = 0;//偏移量
   for (int i = 0; i < n; i++) {
      List value = null;
      if (remainder > 0) {
         value = source.subList(i * number + offset, (i + 1) * number + offset + 1);
         remainder--;
         offset++;
      } else {
         value = source.subList(i * number + offset, (i + 1) * number + offset);
      }
      result.add(value);
   }
   return result;
}

3.main方法测试：

// 运行代码
public static void main(String[] args) {
   List list = new ArrayList<>();
   list.add("1");
   list.add("2");
   list.add("3");
   list.add("4");
   list.add("5");
   list.add("6");
   list.add("7");
   //将一组数据平均分成n组
   List> temps = averageAssign(list, 4);
   int j = 0;
   for (List obj : temps) {
      System.out.println(String.format("row:%s -> size:%s,data:%s", ++j, obj.size(), obj));
   }

   //将一组数据固定分组，每组n个元素
   List> temps2 = split(list, 4);
   int k = 0;
   System.err.println("====================================================================");
   System.err.println("====================================================================");
   System.err.println("====================================================================");
   for (List obj : temps2) {
      System.out.println(String.format("row:%s -> size:%s,data:%s", ++k, obj.size(), obj));
   }
}