java常用工具类

一、有一个list，对list中的数据进行分组

List<List> curriculumIdSplitList = SplitListUtils.splitList(curriculumIds, 20);

for (List<String> curriculumIdSplit : curriculumIdSplitList) {

}

工具类SplitListUtils

package com.speiyou.teacher.data.common;

import java.util.ArrayList;
import java.util.List;


public class SplitListUtils {
    /**
     * 切分list
     * @param sourceList
     * @param groupSize 每组定长
     * @return
     */
    public static List<List> splitList(List sourceList, int groupSize) {
        int length = sourceList.size();
        // 计算可以分成多少组
        int num = (length + groupSize - 1) / groupSize;
        List<List> newList = new ArrayList<>(num);
        for (int i = 0; i < num; i++) {
            // 开始位置
            int fromIndex = i * groupSize;
            // 结束位置
            int toIndex = (i + 1) * groupSize < length ? (i + 1) * groupSize : length;
            newList.add(sourceList.subList(fromIndex, toIndex));
        }
        return newList;
    }

    public static void main(String[] args) {
        List<String> list = new ArrayList<>();
        list.add("1");

        List<List> lists = splitList(list, 2);
        System.out.println("list:" + list.toString());
        System.out.println(lists);
    }

}