一些Tools通用工具方法（根据字段过滤相同值的数据、获取富文本中所有图片、list转map等）

package com.ruoyi.util;

import cn.hutool.core.util.ObjectUtil;
import com.ruoyi.common.aliyun.helper.AliConst;
import com.ruoyi.common.core.domain.BaseEntity;
import com.ruoyi.common.core.domain.BaseEntityPlus;
import com.ruoyi.common.utils.StringUtils;
import com.ruoyi.system.domain.SysFileInfo;

import java.io.UnsupportedEncodingException;
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
import java.util.function.Function;
import java.util.function.Predicate;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * @author Licl
 */
public class Tools {

    public static final Long[] EMPTY_LONG_ARR = {0L};

    public static final String[] EMPTY_STRING_ARR = {""};
    private Object t;

    /**
     * set转数组
     *
     * @param set
     * @return
     */
    public static Long[] set2LongArr(Set<Long> set) {
        if (set.size() > 0) {
            return set.toArray(new Long[set.size()]);
        }
        return EMPTY_LONG_ARR;

    }

    public static String[] set2StrArr(Set<String> set) {
        if (set.size() > 0) {
            return set.toArray(new String[set.size()]);
        }
        return EMPTY_STRING_ARR;
    }

    /**
     * 获取UUID
     *
     * @return UUID
     */
    public static String getUpperCaseUUID() {
        return UUID.randomUUID().toString().replaceAll("-", "").toUpperCase();
    }

    @SuppressWarnings("unchecked")
    public static <K, V> Map<V, K> list2Map(
            @SuppressWarnings("rawtypes") List<? extends BaseEntity> list,
            Function<? super K, ? extends V> mapper) {
        return list
                .stream()
                .filter(e -> mapper.apply((K) e) != null)
                .collect(HashMap::new, (m, v) -> ((Map<K, V>) m).put((K) mapper.apply((K) v), (V) v),
                        HashMap::putAll);
    }

    @SuppressWarnings("unchecked")
    public static <O, K, V> Map<V, K> list2Map(
            @SuppressWarnings("rawtypes") List<? extends BaseEntity> list,
            Function<? super O, ? extends V> key, Function<? super O, ? extends K> value) {
        return list
                .stream()
                .filter(e -> key.apply((O) e) != null)
                .collect(HashMap::new,
                        (m, v) -> ((Map<K, V>) m).put((K) key.apply((O) v), (V) value.apply((O) v)),
                        HashMap::putAll);
    }

    @SuppressWarnings("unchecked")
    public static <K, V> Map<V, K> list2MapPlus(
            @SuppressWarnings("rawtypes") List<? extends BaseEntityPlus> list,
            Function<? super K, ? extends V> mapper) {
        return list
                .stream()
                .filter(e -> mapper.apply((K) e) != null)
                .collect(HashMap::new, (m, v) -> ((Map<K, V>) m).put((K) mapper.apply((K) v), (V) v),
                        HashMap::putAll);
    }

    @SuppressWarnings("unchecked")
    public static <O, K, V> Map<V, K> list2MapPlus(
            @SuppressWarnings("rawtypes") List<? extends BaseEntityPlus> list,
            Function<? super O, ? extends V> key, Function<? super O, ? extends K> value) {
        return list
                .stream()
                .filter(e -> key.apply((O) e) != null)
                .collect(HashMap::new,
                        (m, v) -> ((Map<K, V>) m).put((K) key.apply((O) v), (V) value.apply((O) v)),
                        HashMap::putAll);
    }

    /**
     * 获取随机字符串
     *
     * @param len 字符串你的长度
     * @return
     */
    public static String getRandomJianHan(int len) {
        String ret = "";
        for (int i = 0; i < len; i++) {
            String str = null;
            int hightPos, lowPos;
            Random random = new Random();
            hightPos = (176 + Math.abs(random.nextInt(39)));
            lowPos = (161 + Math.abs(random.nextInt(93)));
            byte[] b = new byte[2];
            b[0] = (new Integer(hightPos).byteValue());
            b[1] = (new Integer(lowPos).byteValue());
            try {
                str = new String(b, "GBK");
            } catch (UnsupportedEncodingException ex) {
                ex.printStackTrace();
            }
            ret += str;
        }
        return ret;
    }

    public static String getName() {
        Random random = new Random();
        String[] surname = {"赵", "钱", "孙", "李", "周", "吴", "郑", "王", "冯", "陈", "褚", "卫", "蒋", "沈", "韩", "杨", "朱", "秦", "尤", "许",
                "何", "吕", "施", "张", "孔", "曹", "严", "华", "金", "魏", "陶", "姜", "戚", "谢", "邹", "喻", "柏", "水", "窦", "章", "云", "苏", "潘", "葛", "奚", "范", "彭", "郎",
                "鲁", "韦", "昌", "马", "苗", "凤", "花", "方", "俞", "任", "袁", "柳", "酆", "鲍", "史", "唐", "费", "廉", "岑", "薛", "雷", "贺", "倪", "汤", "滕", "殷",
                "罗", "毕", "郝", "邬", "安", "常", "乐", "于", "时", "傅", "皮", "卞", "齐", "康", "伍", "余", "元", "卜", "顾", "孟", "平", "黄", "和",
                "穆", "萧", "尹", "姚", "邵", "湛", "汪", "祁", "毛", "禹", "狄", "米", "贝", "明", "臧", "计", "伏", "成", "戴", "谈", "宋", "茅", "庞", "熊", "纪", "舒",
                "屈", "项", "祝", "董", "梁", "杜", "阮", "蓝", "闵", "席", "季"};
        String girl = "秀娟英华慧巧美娜静淑惠珠翠雅芝玉萍红娥玲芬芳燕彩春菊兰凤洁梅琳素云莲真环雪荣爱妹霞香月莺媛艳瑞凡佳嘉琼勤珍贞莉桂娣叶璧璐娅琦晶妍茜秋珊莎锦黛青倩婷姣婉娴瑾颖露瑶怡婵雁蓓纨仪荷丹蓉眉君琴蕊薇菁梦岚苑婕馨瑗琰韵融园艺咏卿聪澜纯毓悦昭冰爽琬茗羽希宁欣飘育滢馥筠柔竹霭凝晓欢霄枫芸菲寒伊亚宜可姬舒影荔枝思丽 ";
        String boy = "伟刚勇毅俊峰强军平保东文辉力明永健世广志义兴良海山仁波宁贵福生龙元全国胜学祥才发武新利清飞彬富顺信子杰涛昌成康星光天达安岩中茂进林有坚和彪博诚先敬震振壮会思群豪心邦承乐绍功松善厚庆磊民友裕河哲江超浩亮政谦亨奇固之轮翰朗伯宏言若鸣朋斌梁栋维启克伦翔旭鹏泽晨辰士以建家致树炎德行时泰盛雄琛钧冠策腾楠榕风航弘";
        int index = random.nextInt(surname.length - 1);
        String name = surname[index];
        int i = random.nextInt(3);
        int b = 2;
        if (i == b) {
            int j = random.nextInt(girl.length() - 2);
            if (j % b == 0) {
                name = name + girl.substring(j, j + 2);
            } else {
                name = name + girl.substring(j, j + 1);
            }

        } else {
            int j = random.nextInt(girl.length() - 2);
            if (j % b == 0) {
                name = name + boy.substring(j, j + 2);
            } else {
                name = name + boy.substring(j, j + 1);
            }

        }
        return name;
    }

    /**
     * 获取文件URL By List<SysFile>
     *
     * @param list sysFileList
     * @return 拼装好的List
     */
    public static List<SysFileInfo> getFileUrl(List<SysFileInfo> list) {
        list.stream().filter(e -> StringUtils.isNotNull(e.getGroupId())).forEach(e -> {
            e.setFilePath(AliConst.HTTPS + AliConst.BUCKET_NAME + "." + AliConst.ENDPOINT
                    + "/" + AliConst.FILE_DIR + e.getGroupId());
        });
        return list;
    }

    public static String getUpperCaseRandomStr() {
        return UUID.randomUUID().toString().replaceAll("-", "").toUpperCase();
    }

    /**
     * 从content中提取一张图片地址作为帖子列表封面图
     * regex：获取<img src="">标签的正则（"<img.*?>"）
     * content：富文本html内容
     */
    public static String getContentImg(String content) {
        //找到图片标签的正则
        String regex = "<img.*?>";
        //文件可能有多张图片
        List<String> pics = new ArrayList<>();
        try {
            Pattern compile = Pattern.compile(regex);
            Matcher matcher = compile.matcher(content);
            while (matcher.find()) {
                String img = matcher.group();
                //获取src中 "" 图片地址的正则
                String httpUrl = "\"http?(.*?)(\"|>|\\s+)";
                Matcher m = Pattern.compile(httpUrl).matcher(img);
                while (m.find()) {
                    String url = m.group();
                    pics.add(url.substring(1, url.length() - 1));
                    return pics.get(0);
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return "";
    }

    /**
     * @return 获取富文本中所有图片
     */
    public static List<String> getContentImgAll(String content) {
        //找到图片标签的正则
        String regex = "<img.*?>";
        //文件可能有多张图片
        List<String> pics = new ArrayList<>();
        try {
            Pattern compile = Pattern.compile(regex);
            Matcher matcher = compile.matcher(content);
            while (matcher.find()) {
                String img = matcher.group();
                //获取src中 "" 图片地址的正则
                String httpUrl = "\"http?(.*?)(\"|>|\\s+)";
                Matcher m = Pattern.compile(httpUrl).matcher(img);
                while (m.find()) {
                    String url = m.group();
                    pics.add(url.substring(1, url.length() - 1));
                    return pics;
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return pics;
    }

    /**
     * 根据字段过滤相同值的数据
     *
     * @param keyExtractor 需要过滤的字段
     * @param <T>          泛型
     * @return void
     */
    public static <T> Predicate<T> distinctByKey(Function<? super T, ?> keyExtractor) {
        ConcurrentHashMap<Object, Boolean> map = new ConcurrentHashMap<>();
        return t -> map.putIfAbsent(keyExtractor.apply(t), Boolean.TRUE) == null;
    }
}