打乱Map key - value的对应顺序

应用场景：对于考试试卷选择题选项的乱序对应问题，防止考生作弊，每个人的题目都是不一样的选项顺序。

package com.muyuan.platform.elearning.util;

import com.alibaba.fastjson.JSONObject;
import com.muyuan.platform.elearning.vo.exam.QuestionVo;

import java.util.*;

/**
 * 乱序工具类
 */
public class QuestionSelectRevertUtils {

    /**
     * 打乱Map key-value顺序，重新组合key-value
     *
     * @param questionJson
     * @return
     */
    public static Map<String, String> toDisOrder(String questionJson) {
        QuestionVo questionVo = JSONObject.parseObject(questionJson, QuestionVo.class);
        Map<String, String> map = questionVo.getOptionsMap();
        String correctValue = map.get(questionVo.getCorrectOptions());
        List<String> valueList = new ArrayList<>();
        List<String> keyList = new ArrayList<>();
        for (Map.Entry<String, String> entry : map.entrySet()) {
            keyList.add(entry.getKey());
            valueList.add(entry.getValue());
        }
        Collections.shuffle(valueList);
        HashMap<String, String> revertMap = new HashMap<>();
        for (int i = 0; i < keyList.size(); i++) {
            revertMap.put(keyList.get(i), valueList.get(i));
        }
        QuestionVo vo = new QuestionVo();
        for (Map.Entry<String, String> entry : revertMap.entrySet()) {
            if (entry.getValue().equals(correctValue)) {
                vo.setCorrectOptions(entry.getKey());
                vo.setCorrectValue(correctValue);
            }
        }
        vo.setOptionsMap(revertMap);
        vo.setQuestionContent(questionVo.getQuestionContent());
        System.out.println("revertMap: " + JSONObject.toJSON(vo));
        return revertMap;
    }

    public static String setOptions() {
        QuestionVo questionVo = new QuestionVo();
        questionVo.setQuestionContent("中华人民共和国的首都是哪里？");
        Map<String, String> map = new HashMap<>();
        map.put("A", "北京");
        map.put("B", "天津");
        map.put("C", "上海");
        map.put("D", "重庆");
        questionVo.setOptionsMap(map);
        questionVo.setCorrectOptions("A");
        questionVo.setCorrectValue("北京");
        System.out.println("originMap: " + JSONObject.toJSON(questionVo));
        return JSONObject.toJSONString(questionVo);
    }

    public static void main(String[] args) {
        String s = setOptions();
        System.out.println("\r\n");
        int i = 0;
        while (i < 10) {
            toDisOrder(s);
            i++;
        }
    }
}

输出结果：

originMap: {"questionContent":"中华人民共和国的首都是哪里？","correctValue":"北京","optionsMap":{"A":"北京","B":"天津","C":"上海","D":"重庆"},"correctOptions":"A"}

revertMap: {"questionContent":"中华人民共和国的首都是哪里？","correctValue":"北京","optionsMap":{"A":"重庆","B":"上海","C":"天津","D":"北京"},"correctOptions":"D"}
revertMap: {"questionContent":"中华人民共和国的首都是哪里？","correctValue":"北京","optionsMap":{"A":"北京","B":"上海","C":"重庆","D":"天津"},"correctOptions":"A"}
revertMap: {"questionContent":"中华人民共和国的首都是哪里？","correctValue":"北京","optionsMap":{"A":"上海","B":"重庆","C":"天津","D":"北京"},"correctOptions":"D"}
revertMap: {"questionContent":"中华人民共和国的首都是哪里？","correctValue":"北京","optionsMap":{"A":"重庆","B":"北京","C":"天津","D":"上海"},"correctOptions":"B"}
revertMap: {"questionContent":"中华人民共和国的首都是哪里？","correctValue":"北京","optionsMap":{"A":"北京","B":"天津","C":"上海","D":"重庆"},"correctOptions":"A"}
revertMap: {"questionContent":"中华人民共和国的首都是哪里？","correctValue":"北京","optionsMap":{"A":"天津","B":"北京","C":"上海","D":"重庆"},"correctOptions":"B"}
revertMap: {"questionContent":"中华人民共和国的首都是哪里？","correctValue":"北京","optionsMap":{"A":"上海","B":"重庆","C":"天津","D":"北京"},"correctOptions":"D"}
revertMap: {"questionContent":"中华人民共和国的首都是哪里？","correctValue":"北京","optionsMap":{"A":"北京","B":"重庆","C":"天津","D":"上海"},"correctOptions":"A"}
revertMap: {"questionContent":"中华人民共和国的首都是哪里？","correctValue":"北京","optionsMap":{"A":"上海","B":"重庆","C":"北京","D":"天津"},"correctOptions":"C"}
revertMap: {"questionContent":"中华人民共和国的首都是哪里？","correctValue":"北京","optionsMap":{"A":"上海","B":"重庆","C":"北京","D":"天津"},"correctOptions":"C"}