java 实现每次从list中取5000条数据放入新list

Posted 2021-12-04 winddogg

public static <T> List<List<T>> split(List<T> resList, int count) { 
if (resList == null || count < 1) 
return null; 
List<List<T>> ret = new ArrayList<List<T>>(); 
int size = resList.size(); 
if (size <= count) { 
// 数据量不足count指定的大小 
ret.add(resList); 
} else { 
int pre = size / count; 
int last = size % count; 
// 前面pre个集合，每个大小都是count个元素 
for (int i = 0; i < pre; i++) { 
List<T> itemList = new ArrayList<T>(); 
for (int j = 0; j < count; j++) { 
itemList.add(resList.get(i * count + j)); 
} 
ret.add(itemList); 
} 
// last的进行处理 
if (last > 0) { 
List<T> itemList = new ArrayList<T>(); 
for (int i = 0; i < last; i++) { 
itemList.add(resList.get(pre * count + i)); 
} 
ret.add(itemList); 
} 
} 
return ret; 
}