String轉成JSON

這個依賴很重要，我們將圍繞fastjson中的JSONObject這個類來談轉換

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 <dependency>
 <groupId>com.alibaba</groupId>
 <artifactId>fastjson</artifactId>
 <version>1.2.15</version>
 </dependency>

1. String轉成JSON

String json = "{"abc":"1","hahah":"2"}";
JSONObject jsonObject = JSONObject.parseObject(content);
一句話就能解決，非常便捷。
想要取出值，可以對`jsonObject`進行操作：
jsonObject.getString("abc");
結果為：`1`

1. 將String轉為list後轉為JSON

List<String> list = new ArrayList<String>(); 
list.add("username"); 
list.add("age"); 
list.add("sex"); 
JSONArray array = new JSONArray(); 
array.add(list); 

1. 將String轉為map後轉為JSON

Map<String, String> map = new HashMap<String, String>();
 map.put("abc", "abc");
map.put("def", "efg");
JSONArray array_test = new JSONArray();
array_test.add(map);
 JSONObject jsonObject = JSONObject.fromObject(map);

特別注意:從JSONObject中取值，碰到了數字為key的時候，如

{
 "userAnswer": {
 "28568": {
 "28552": {
 "qId": "28552",
 "order": "1",
 "userScore": {
 "score": 100
 },
 "answer": {
 "28554": "28554"
 },
 "qScore": "100.0",
 "qtype": "SingleChoice",
 "sId": "28568"
 }
 }
 },
 "paperType": "1",
 "paperOid": "28567",
 "instanceId": 30823,
 "remainingTime": -1,
 "examOid": "28570"
}
獲取“userAnswer”的value,再轉成JSON,可仿照如下形式：
JSONObject userJson = JSONObject.parseObject(jsonObject.getString("userAnswer"));
但是想獲取key"28568"就沒這麼容易了。直接像上述的寫法，會報錯。
我們瀏覽fastjson中的原始碼，總結下，應該如下寫：
JSONObject question = (JSONObject) JSONObject.parseObject(section.getString("28568"), Object.class);

整體程式碼：

dao程式碼很容易，就不貼出來了。
package com.xiamenair.training.business.service;
import com.alibaba.fastjson.JSONObject;
import com.xiamenair.training.business.dao.elearningdao.ELearningExamInstanceDao;
import com.xiamenair.training.business.dao.masterdao.ELearningChoiceRecordDao;
import com.xiamenair.training.business.model.LasChoiceRecord;
import com.xiamenair.training.business.model.entity.elearning.LasExamInstance;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Service;
import java.math.BigDecimal;
import java.sql.Blob;
import java.sql.SQLException;
import java.text.SimpleDateFormat;
import java.util.*;
@Service
public class ChoiceRecordService {
 //查詢資料Dao
 @Autowired
 private ELearningChoiceRecordDao eLearningChoiceRecordDao;
 //轉儲資料Dao
 @Autowired
 private ELearningExamInstanceDao eLearningExamInstanceDao;
 private ChoiceRecordService() {
 }
 private static class SingletonRecordInstance {
 private static final LasChoiceRecord choiceRecord = new LasChoiceRecord();
 }
 public static LasChoiceRecord getMapInstance() {
 return SingletonRecordInstance.choiceRecord;
 }
 private static SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd");
 /**
 * 定時任務，每天定時將E學網考試資料分析並轉儲
 *
 * @param : instanceIdList
 * @return : void
 * @author : 28370·皮育才
 * @date : 2018/11/20
 **/
 @Scheduled(cron = "00 00 01 * * ?")
 public void analysisChoiceRecord() {
 //獲取前一天的時間
 Date date = new Date();
 Calendar calendar = Calendar.getInstance();
 calendar.setTime(date);
 calendar.add(calendar.DATE, -1);
 date = calendar.getTime();
 String dateString = simpleDateFormat.format(date);
 List<BigDecimal> instanceIdList = eLearningExamInstanceDao.findInstanceIdByFinishTime(dateString);
 if(0 != instanceIdList.size()){
 LasChoiceRecord lasChoiceRecord = getMapInstance();
 instanceIdList.stream().forEach(instanceId -> {
 Blob answerBlob = eLearningExamInstanceDao.findUserAnswer(instanceId);
 Long userId = eLearningExamInstanceDao.findUserId(instanceId);
 String content = null;
 try {
 content = new String(answerBlob.getBytes((long) 1, (int) answerBlob.length()));
 } catch (SQLException e) {
 e.printStackTrace();
 System.out.println("SQLEXCEPTION:" + e);
 }
 JSONObject jsonObject = JSONObject.parseObject(content);
 //針對本section的"公共"屬性直接設定
 lasChoiceRecord.setUserId(userId);
 lasChoiceRecord.setPaperType(jsonObject.getString("paperType"));
 lasChoiceRecord.setPaperId(jsonObject.getString("paperOid"));
 lasChoiceRecord.setExamInstanceId(jsonObject.getString("instanceId"));
 lasChoiceRecord.setRemainingTime(jsonObject.getString("remainingTime"));
 lasChoiceRecord.setExamId(jsonObject.getString("examOid"));
 //針對section中的題目進行細化迴圈拆分
 JSONObject userJson = JSONObject.parseObject(jsonObject.getString("userAnswer"));
 Set sectionSet = userJson.keySet();
 Iterator<String> setIt = sectionSet.iterator();
 analyzeAnswer(lasChoiceRecord, userJson, setIt);
 });
 }
 }
 private void analyzeAnswer(LasChoiceRecord lasChoiceRecord, JSONObject userJson, Iterator<String> setIt) {
 while (setIt.hasNext()) {
 //對每個question進行再次拆分出題目
 JSONObject section = (JSONObject) JSONObject.parseObject(userJson.getString(setIt.next()), Object.class);
 Set questionSet = section.keySet();
 Iterator<String> queIt = questionSet.iterator();
 while (queIt.hasNext()) {
 JSONObject question = (JSONObject) JSONObject.parseObject(section.getString(queIt.next()), Object.class);
 String userAnswer = question.getString("answer");
 String userScore = question.getString("userScore");
 lasChoiceRecord.setQuestionId(question.getString("qId"));
 lasChoiceRecord.setRecordId(UUID.randomUUID().toString());
 eLearningChoiceRecordDao.save(lasChoiceRecord);
 }
 }
 }
}