JslOrderService/src/main/java/com/qs/cost/common/utils/CollectionUtil.java

package com.qs.cost.common.utils;

import java.util.*;

/**
 * 常用数据工具类
 *
 * @Author JcYen
 * @Date 2019/5/23
 * @Version 1.0
 */
public class CollectionUtil {

    private CollectionUtil() {
        super();
    }

    /**
     * 判断一个集合是否为空
     */
    public static <T> boolean isEmpty(Collection<T> col) {
        if (col == null || col.isEmpty()) {
            return true;
        }
        return false;
    }

    public static <T> List<T> setToList(Set<T> colSet){
        if (colSet == null || colSet.isEmpty()){
            return new ArrayList<>();
        }
        List<T> rs = new ArrayList<>(colSet);
        return rs;
    }

    /**
     * 判断一个集合是否不为空
     */
    public static <T> boolean isNotEmpty(Collection<T> col) {
        return !isEmpty(col);
    }

    /**
     * 判断Map是否为空
     */
    public static <K, V> boolean isEmpty(Map<K, V> map) {
        if (map == null || map.isEmpty()) {
            return true;
        }
        return false;
    }

    /**
     * 判断Map是否不为空为空
     */
    public static <K, V> boolean isNotEmpty(Map<K, V> map) {
        return !isEmpty(map);
    }

    /**
     * 去除list中的重复数据
     */
    public static <T> List<T> removeRepeat(List<T> list) {
        if (isEmpty(list)) {
            return list;
        }
        List<T> result = new ArrayList<T>();
        for (T e : list) {
            if (!result.contains(e)) {
                result.add(e);
            }
        }
        return result;
    }

    public static boolean hasNull(Object... objects){
        for (int i = 0; i < objects.length; i++) {
            if(objects[i]==null){return true;}
        }
        return false;
    }

    public static boolean hasNotNull(Object... objects){
        for (int i = 0; i < objects.length; i++) {
            if(objects[i]!=null){return true;}
        }
        return false;
    }

    /**
     * 将集合转换为String数组
     */
    public static <T> String[] toArray(List<T> list) {
        if (isEmpty(list)) {
            return null;
        }
        String[] result = new String[list.size()];
        for (int i = 0; i < list.size(); i++) {
            result[i] = String.valueOf(list.get(i));
        }
        return result;
    }

    /**
     * 将list拆分成多给指定的大小的list
     */
    public static <T> List<List<T>>  createList(List<T> target, int size) {
        List<List<T>> listArr = new ArrayList<>();
        //获取被拆分的数组个数
        int arrSize = target.size()%size==0?target.size()/size:target.size()/size+1;
        for(int i=0;i<arrSize;i++) {
            List<T>    sub = new ArrayList<T>();
            //把指定索引数据放入到list中
            for(int j=i*size;j<=size*(i+1)-1;j++) {
                if(j<=target.size()-1) {
                    sub.add(target.get(j));
                }
            }
            listArr.add(sub);
        }
        return listArr;
    }

    public static <T> T selectFirst(List<T> list){
        if(isNotEmpty(list)){
            return list.get(0);
        }
        return null;
    }

}