数组分割工具类，方便多线程任务处理。

import java.util.*;

/**
 * 数组拆分工具类
 */
public class SplitListUtils {
    /**
     * 待分割数组
     */
    private List dataList;
    /**
     * 分成几组
     */
    private int n;
    /**
     * 数组大小
     */
    private int len;

    public SplitListUtils(List dataList, int n) {
        this.dataList = dataList;
        this.n = n;
        // dataList不为null且不为空
        this.len = (!Objects.isNull(dataList) && dataList.size() > 0) ? dataList.size() : 0;
    }

    /**
     * list校验避免出现算数异常
     */
    public void check() {
        if (Objects.isNull(dataList)) {
            throw new RuntimeException("dataList为null");
        }
        if (dataList.size() == 0) {
            throw new RuntimeException("dataList为空");
        }
    }

    /**
     * 将list平均分成n组，多出来的部分进行分摊
     *
     * @return
     */
    public List> split() {
        check();
        int number = len / n;
        int remainder = len % n;
        List> result = new ArrayList<>();
        int offset = 0;
        for (int i = 0; i < n; ++i) {
            if (remainder > 0) {
                result.add(this.dataList.subList(i * number + offset, (i + 1) * number + 1 + offset));
                remainder--;
                offset++;
            } else {
                result.add(this.dataList.subList(i * number + offset, (i + 1) * number + offset));
            }
        }
        return result;
    }

    public static void main(String[] args) {
        List list = new ArrayList<>();
        for (int i = 1; i <= 15; ++i) {
            list.add(i);
        }
        System.out.println(new SplitListUtils(list, 4).split());
    }
}