我們將圍繞fastjson中的JSONObject這個類來談轉換
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.15</version>
</dependency>
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");
結果爲:`1`
將String轉爲list後轉爲JSON
List<String> list = new ArrayList<String>();
list.add("username");
list.add("age");
list.add("sex");
JSONArray array = new JSONArray();
array.add(list);
將String轉爲map後轉爲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,碰到了數字爲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中的源碼,總結下,應該如下寫:
JSONObject question = (JSONObject) JSONObject.parseObject(section.getString("28568"), Object.class);
整體代碼:
dao代碼很容易,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 {
//查詢數據Dao
@Autowired
private ELearningChoiceRecordDao eLearningChoiceRecordDao;
//轉儲數據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學網考試數據分析並轉儲
*
* @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"屬性直接設置
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中的題目進行細化循環拆分
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);
}
}
}
}
最近研究java的東西。之前靠着自己的摸索,實現了把java對象轉成json格式的數據的功能,返回給前端。當時使用的是 JSONObject.fromObject(object) 方法把java對象換成json格式。也就是先有一個java實體類,例如叫User。然後從數據庫查出列表數據,也就是一個List,裏面的每一條數據都是一個User的實體對象。而如果前端需求變化,需要在當前這個接口中多返回一個字段時,就需要修改這個User實體類,新增字段。這樣一來,所有用到這個User實體類的接口的地方,接口返回的json數據裏都會有新增的這個字段。後來發現可以用一下方法根據需要動態拼接需要的字段。
package com.lin.domain;
import net.sf.json.JSONArray;
import net.sf.json.JSONObject;
public class Test {
public static void main(String[] args) throws Exception {
JSONObject createJSONObject = createJSONObject();
System.out.println(createJSONObject);
}
// 創建JSONObject對象
private static JSONObject createJSONObject() {
JSONObject result = new JSONObject();
result.put("success", true);
result.put("totalCount", "30");
JSONObject user1 = new JSONObject();
user1.put("id", "12");
user1.put("name", "張三");
user1.put("createTime", "2017-11-16 12:12:12");
JSONObject user2 = new JSONObject();
user2.put("id", "13");
user2.put("name", "李四");
user2.put("createTime", "2017-11-16 12:12:15");
JSONObject department = new JSONObject();
department.put("id", 1);
department.put("name","技術部");
user1.put("department", department);
user2.put("department", department);
// 返回一個JSONArray對象
JSONArray jsonArray = new JSONArray();
jsonArray.add(0, user1);
jsonArray.add(1, user2);
result.element("data", jsonArray);
return result;
}
}
返回的Json數據:
下面是真實的接口代碼,從數據庫中查詢數據:
@ResponseBody
@RequestMapping(value="/getRoleMenuList.do", method=RequestMethod.GET)
public void getRoleMenuList(HttpServletRequest req, HttpServletResponse res, Integer roleId) throws IOException{
res.setHeader("Content-type", "application/json;charset=UTF-8");
res.setCharacterEncoding("UTF-8");
ResListData rld = new ResListData();
JSONObject result = new JSONObject();
try {
Map<String, Object> params1 = new HashMap<>();
params1.put("roleId", roleId);
params1.put("menuLevel", 1);
List<RoleJuri> fMenuList = rjService.getRoleMenuList2(params1); //一級菜單
JSONArray firstList = new JSONArray();
for(int i=0; i<fMenuList.size(); i++){
RoleJuri firstMenu = fMenuList.get(i);
JSONObject firstResult = new JSONObject();
firstResult.put("id", firstMenu.getId());
firstResult.put("name", firstMenu.getMenuName());
firstResult.put("url", firstMenu.getMenuUrl());
Map<String, Object> params2 = new HashMap<>();
params2.put("roleId", roleId);
params2.put("menuPId", firstMenu.getMenuId());
List<RoleJuri> sMenuList = rjService.getRoleMenuList2(params2); //二級菜單
JSONArray secondList = new JSONArray();
for(int j=0; j<sMenuList.size(); j++){
RoleJuri secondMenu = sMenuList.get(j);
JSONObject secondResult = new JSONObject();
secondResult.put("id", secondMenu.getId());
secondResult.put("name", secondMenu.getMenuName());
secondResult.put("url", secondMenu.getMenuUrl());
secondList.add(secondResult);
}
firstResult.put("children", secondList);
firstList.add(firstResult);
}
if(fMenuList.size() > 0){ //查詢到了一級菜單
result.put("success", 1);
result.put("data", firstList);
}else{ //未查詢到一級菜單
result.put("success", 0);
result.put("data", new Array());
result.put("error", "未獲取到菜單數據");
}
} catch (Exception e) {
result.put("success", 0);
result.put("data", new Array());
result.put("error", "服務器運行錯誤");
}
res.getWriter().write(result.toString());
}
返回的Json數據:
參考:
https://www.cnblogs.com/libo0125ok/p/7905665.html
https://blog.csdn.net/javaQQ561487941/article/details/84328669
https://www.cnblogs.com/LearnAndGet/p/10009646.html