Qt实现json数据的生成、解析、修改和删除

文章介绍

• 本文章主要介绍如何使用QT提供的json相关类来处理json数据，包括json数据的生成、解析、修改和json数据的删除。

json数据的增删改查

• 处理json数据时需要包含以下三个头文件

  •   #include 
      #include 
      #include 
    

json数据生成

• json数据

  •   {  
          "id":1001,
          "name":"jack",
          "sex":true
      }
    

• 代码

  •   // 创建json数据对象
      QJsonObject json;
      json.insert("name", "jack");
      json.insert("id", 1001);
      json.insert("sex", true);
    
    
      QJsonDocument document;   // 创建json文档
      document.setObject(json); // 给json文档设置json数据对象
      // 将json数据对象转为字符串
      QByteArray byJsonData = document.toJson(QJsonDocument::Compact);
      QString strJson(byJsonData);
    

嵌套json数据生成

• json数据

  •   {
          "id": 1002,
          "name": "Tom",
          "scoreData":{
              "Chinese":96,
              "English":82,
              "Math":90
          },
          "sex":true
      }
    

• 代码

  •   // 创建子节点scoreData的json数据对象
      QJsonObject scoreObject;
      scoreObject.insert("Math", 90);
      scoreObject.insert("Chinese", 96);
      scoreObject.insert("English", 82);
    
      // 创建json数据对象
      QJsonObject json;
      json.insert("name", "Tom");
      json.insert("id", 1002);
      json.insert("sex", true);
      json.insert("scoreData", QJsonValue(scoreObject));
    
      QJsonDocument document;
      document.setObject(json);
      QByteArray byJsonData = document.toJson(QJsonDocument::Compact);
      QString strJson(byJsonData);
    

包含数组的json数据生成

• json数据

  •   {
          "id":1002,
          "name": "Tom",
          "scoreData":{
              "Chinese":96,
              "English":82,
              "Math":90
          },
          "sex": true,
          "techData":["C++", "JAVA", "PYTHON"]
      }
    

• 代码

  •   // 创建json数组对象
      QJsonArray techArray;
      techArray.append("C++");
      techArray.append("JAVA");
      techArray.append("PYTHON");
    
      // 创建子节点scoreData的json数据对象
      QJsonObject scoreObject;
      scoreObject.insert("Math", 90);
      scoreObject.insert("Chinese", 96);
      scoreObject.insert("English", 82);
    
      // 创建json对象
      QJsonObject json;
      json.insert("name", "Tom");
      json.insert("id", 1002);
      json.insert("sex", true);
      json.insert("scoreData", QJsonValue(scoreObject));
      json.insert("techData", QJsonValue(techArray));
    
    
      QJsonDocument document;
      document.setObject(json);
      QByteArray byJsonData = document.toJson(QJsonDocument::Compact);
      QString strJson(byJsonData);
    

包含数组对象的json数据生成

• json数据

  •   {
          "id":1002,
          "name": "Tom",
          "schoolData":[
              {"schoolCity":"Xian","schoolName":"xiaoxue"},
              {"schoolCity":"Xian","schoolName":"zhongxue"},
              {"schoolCity":"Beijing","schoolName":"daxue"}
          ],
          "scoreData":{
              "Chinese":96,
              "English":82,
              "Math":90
          },
          "sex":true
      }
    

• 代码

  •   // 创建json数组
      QJsonArray SchoolArray;
    
      QJsonObject primarySchoolObj;
      primarySchoolObj.insert("schoolName", "xiaoxue");
      primarySchoolObj.insert("schoolCity", "Xian");
    
      QJsonObject middleSchoolObj;
      middleSchoolObj.insert("schoolName", "zhongxue");
      middleSchoolObj.insert("schoolCity", "Xian");
    
      QJsonObject universityObj;
      universityObj.insert("schoolName", "daxue");
      universityObj.insert("schoolCity", "Beijing");
    
      // json数组中插入json数据对象
      SchoolArray.append(primarySchoolObj);
      SchoolArray.append(middleSchoolObj);
      SchoolArray.append(universityObj);
    
      // 创建子节点scoreData的json数据对象
      QJsonObject scoreObject;
      scoreObject.insert("Math", 90);
      scoreObject.insert("Chinese", 96);
      scoreObject.insert("English", 82);
    
      // 创建json数据
      QJsonObject json;
      json.insert("name", "Tom");
      json.insert("id", 1002);
      json.insert("sex", true);
      json.insert("scoreData", QJsonValue(scoreObject));
      json.insert("schoolData", QJsonValue(SchoolArray));
    
      QJsonDocument document;
      document.setObject(json);
      QByteArray byJsonData = document.toJson(QJsonDocument::Compact);
      QString strJson(byJsonData);
    

json数据解析

• json数据

  •   {
          "sex":true,
          "id":1001,
          "name":"jack"
      }
    

• 解析结果

  •   strName "jack"
      iId 1001
      bSex true
    

• 代码

  •   QByteArray jsonData = "{\"sex\":true,\"id\":1001,\"name\":\"jack\"}";
    
      // 将字符串转为json文档
      QJsonParseError result;
      QJsonDocument rootDoc = QJsonDocument::fromJson(jsonData, &result);
      if(rootDoc.isNull() || result.error != QJsonParseError::NoError){
          qDebug() << "parse json data failed.";
          return false;
      }
    
      // 获取根对象
      QJsonObject rootObj = rootDoc.object();
    
      // 解析json数据
      QJsonValue nameValue = rootObj.value("name");
      QString strName = nameValue.toString();
      qDebug() << "strName" << strName;
    
      QJsonValue idValue = rootObj.value("id");
      int iId = idValue.toInt();
      qDebug() << "iId" << iId;
    
      QJsonValue sexValue = rootObj.value("sex");
      bool bSex = sexValue.toBool();
      qDebug() << "bSex" << bSex;
    

嵌套json数据解析

• json数据

  •   {
          "id":1002,
          "name":"Tom",
          "scoreData":{
              "Chinese":96,
              "English":82,
              "Math":90
          },
          "sex":true
      }
    

• 解析结果

  •   strName "Tom"
      iId 1002
      bSex true
      iChinese 96
      iEnglish 82
      iMath 90
    

• 代码

  •   QByteArray jsonData = "{\"id\":1002,\"name\":\"Tom\",\"scoreData\":{\"Chinese\":96,\"English\":82,\"Math\":90},\"sex\":true}";
    
      QJsonParseError result;
      QJsonDocument rootDoc = QJsonDocument::fromJson(jsonData, &result);
      if(rootDoc.isNull() || result.error != QJsonParseError::NoError){
          qDebug() << "parse json data failed.";
          return false;
      }
    
      // 获取根对象
      QJsonObject rootObj = rootDoc.object();
    
      // 解析json数据
      QJsonValue nameValue = rootObj.value("name");
      QString strName = nameValue.toString();
      qDebug() << "strName" << strName;
    
      QJsonValue idValue = rootObj.value("id");
      int iId = idValue.toInt();
      qDebug() << "iId" << iId;
    
      QJsonValue sexValue = rootObj.value("sex");
      bool bSex = sexValue.toBool();
      qDebug() << "bSex" << bSex;
    
      // 解析scoreData节点的json数据
      QJsonValue scoreDataValue = rootObj.value("scoreData");
      QJsonObject scoreDataObj = scoreDataValue.toObject();
    
      QJsonValue chineseValue = scoreDataObj.value("Chinese");
      int iChinese = chineseValue.toInt();
      qDebug() << "iChinese" << iChinese;
    
      QJsonValue englishValue = scoreDataObj.value("English");
      int iEnglish = englishValue.toInt();
      qDebug() << "iEnglish" << iEnglish;
    
      QJsonValue mathValue = scoreDataObj.value("Math");
      int iMath = mathValue.toInt();
      qDebug() << "iMath" << iMath;
    

包含数组的json数据解析

• json数据

  •   {
          "id":1002,
          "name":"Tom",
          "scoreData":{
              "Chinese":96,
              "English":82,
              "Math":90
          },
          "sex":true,
          "techData":["C++", "JAVA", "PYTHON"]
      }
    

• 解析结果

  •   strName "Tom"
      iId 1002
      bSex true
      iChinese 96
      iEnglish 82
      iMath 90
      str "C++"
      str "JAVA"
      str "PYTHON"
    

• 代码

  •   QByteArray jsonData = "{\"id\":1002,\"name\":\"Tom\",\"scoreData\":{\"Chinese\":96,\"English\":82,\"Math\":90},\"sex\":true,\"techData\":[\"C++\",\"JAVA\",\"PYTHON\"]}";
    
      QJsonParseError result;
      QJsonDocument rootDoc = QJsonDocument::fromJson(jsonData, &result);
      if(rootDoc.isNull() || result.error != QJsonParseError::NoError){
          qDebug() << "parse json data failed.";
          return false;
      }
    
      // 获取根对象
      QJsonObject rootObj = rootDoc.object();
    
      // 解析json数据
      QJsonValue nameValue = rootObj.value("name");
      QString strName = nameValue.toString();
      qDebug() << "strName" << strName;
    
      QJsonValue idValue = rootObj.value("id");
      int iId = idValue.toInt();
      qDebug() << "iId" << iId;
    
      QJsonValue sexValue = rootObj.value("sex");
      bool bSex = sexValue.toBool();
      qDebug() << "bSex" << bSex;
    
      // 解析scoreData节点的json数据
      QJsonValue scoreDataValue = rootObj.value("scoreData");
      QJsonObject scoreDataObj = scoreDataValue.toObject();
    
      QJsonValue chineseValue = scoreDataObj.value("Chinese");
      int iChinese = chineseValue.toInt();
      qDebug() << "iChinese" << iChinese;
    
      QJsonValue englishValue = scoreDataObj.value("English");
      int iEnglish = englishValue.toInt();
      qDebug() << "iEnglish" << iEnglish;
    
      QJsonValue mathValue = scoreDataObj.value("Math");
      int iMath = mathValue.toInt();
      qDebug() << "iMath" << iMath;
    
      // 解析techData数组中的json数据
      QJsonValue techDataValue = rootObj.value("techData");
      QJsonArray techDataArray = techDataValue.toArray();
      for(int i = 0; i < techDataArray.size(); i++){
          QJsonValue value = techDataArray.at(i);
          QString str = value.toString();
          qDebug() << "str" << str;
      }
    

包含数组对象的json数据解析

• json数据

  •   {
          "id":1002,
          "name":"Tom",
          "schoolData":[
              {
                  "schoolCity":"Xian",
                  "schoolName":"xiaoxue"
              },
              {
                  "schoolCity":"Xian",
                  "schoolName":"zhongxue"
              },
              {
                  "schoolCity":"Beijing",
                  "schoolName":"daxue"
              }
          ],
          "scoreData":{
              "Chinese":96,
              "English":82,
              "Math":90
          },
          "sex":true
      }
    

• 解析结果

  •   strName "Tom"
      iId 1002
      bSex true
      iChinese 96
      iEnglish 82
      iMath 90
      strSchoolname "xiaoxue"
      strSchoolcity "Xian"
      strSchoolname "zhongxue"
      strSchoolcity "Xian"
      strSchoolname "daxue"
      strSchoolcity "Beijing"
    

• 代码

  •   QByteArray jsonData = "{\"id\":1002,\"name\":\"Tom\",\"schoolData\":[{\"schoolCity\":\"Xian\",\"schoolName\":\"xiaoxue\"},{\"schoolCity\":\"Xian\",\"schoolName\":\"zhongxue\"},{\"schoolCity\":\"Beijing\",\"schoolName\":\"daxue\"}],\"scoreData\":{\"Chinese\":96,\"English\":82,\"Math\":90},\"sex\":true}";
    
      QJsonParseError result;
      QJsonDocument rootDoc = QJsonDocument::fromJson(jsonData, &result);
      if(rootDoc.isNull() || result.error != QJsonParseError::NoError){
          qDebug() << "parse json data failed.";
          return false;
      }
    
      // 获取根对象
      QJsonObject rootObj = rootDoc.object();
    
      // 解析json数据
      QJsonValue nameValue = rootObj.value("name");
      QString strName = nameValue.toString();
      qDebug() << "strName" << strName;
    
      QJsonValue idValue = rootObj.value("id");
      int iId = idValue.toInt();
      qDebug() << "iId" << iId;
    
      QJsonValue sexValue = rootObj.value("sex");
      bool bSex = sexValue.toBool();
      qDebug() << "bSex" << bSex;
    
      // 解析scoreData节点的json数据
      QJsonValue scoreDataValue = rootObj.value("scoreData");
      QJsonObject scoreDataObj = scoreDataValue.toObject();
    
      QJsonValue chineseValue = scoreDataObj.value("Chinese");
      int iChinese = chineseValue.toInt();
      qDebug() << "iChinese" << iChinese;
    
      QJsonValue englishValue = scoreDataObj.value("English");
      int iEnglish = englishValue.toInt();
      qDebug() << "iEnglish" << iEnglish;
    
      QJsonValue mathValue = scoreDataObj.value("Math");
      int iMath = mathValue.toInt();
      qDebug() << "iMath" << iMath;
    
      // 解析schoolData数组对象的json数据
      QJsonValue schoolDataValue = rootObj.value("schoolData");
      QJsonArray schoolDataValueArray = schoolDataValue.toArray();
    
      for(int i = 0; i < schoolDataValueArray.size(); i++){
          QJsonValue value = schoolDataValueArray.at(i);
          QJsonObject obj = value.toObject();
    
          QJsonValue schoolnameValue = obj.value("schoolName");
          QString strSchoolname = schoolnameValue.toString();
          qDebug() << "strSchoolname" << strSchoolname;
    
          QJsonValue schoolcityValue = obj.value("schoolCity");
          QString strSchoolcity = schoolcityValue.toString();
          qDebug() << "strSchoolcity" << strSchoolcity;
      }
    

json数据修改

• 原始json数据

  •   {
          "id":1002,
          "name":"Tom",
          "techData":["C++","JAVA","PYTHON"], 
          "schoolData":[
              {"schoolCity":"Xian","schoolName":"xiaoxue"},
              {"schoolCity":"Xian","schoolName":"zhongxue"},
              {"schoolCity":"Beijing","schoolName":"daxue"}
          ],
          "scoreData":{
              "Chinese":96,
              "English":82,
              "Math":90
          },
          "sex":true
      }
    

• 修改后的json数据

  •   {
          "id":1002,
          "name":"Jack", // Tom修改为Jack
          "techData":["C++","JAVA","GO"], // PYTHON修改为GO 
          "schoolData":[
              {"schoolCity":"Baoji","schoolName":"xiaoxue"}, // Xian改为Baoji
              {"schoolCity":"Xian","schoolName":"zhongxue"},
              {"schoolCity":"Beijing","schoolName":"daxue"}
          ],
          "scoreData":{
              "Chinese":100, // 96修改为100
              "English":82,
              "Math":90
          },
          "sex":true
      }
    

• 代码

  •   QByteArray jsonData = "{\"id\":1002,\"name\":\"Tom\",\"techData\":[\"C++\",\"JAVA\",\"PYTHON\"], \"schoolData\":[{\"schoolCity\":\"Xian\",\"schoolName\":\"xiaoxue\"},{\"schoolCity\":\"Xian\",\"schoolName\":\"zhongxue\"},{\"schoolCity\":\"Beijing\",\"schoolName\":\"daxue\"}],\"scoreData\":{\"Chinese\":96,\"English\":82,\"Math\":90},\"sex\":true}";
    
      // 将json数据转为json文档
      QJsonParseError result;
      QJsonDocument rootDoc = QJsonDocument::fromJson(jsonData, &result);
      if(rootDoc.isNull() || result.error != QJsonParseError::NoError){
          qDebug() << "parse json data failed.";
          return false;
      }
    
      // 获取根对象
      QJsonObject rootObj = rootDoc.object();
    
      // 修改数据
      rootObj["name"] = "Jack";
    
      // 修改数据对象
      QJsonValue scoreDataValue = rootObj.value("scoreData");
      QJsonObject scoreDataObj = scoreDataValue.toObject();
      scoreDataObj["Chinese"] = 100;
      rootObj["scoreData"] = scoreDataObj;
    
      // 修改数组
      QJsonValue techDataValue = rootObj.value("techData");
      QJsonArray techDataArray = techDataValue.toArray();
      for(int i = 0; i < techDataArray.size(); i++){
          if(techDataArray.at(i).toString().compare("PYTHON") == 0){
              techDataArray.replace(i, "GO");
              break;
          }
      }
      rootObj["techData"] = techDataArray;
    
      // 修改数组对象
      QJsonValue schoolDataValue = rootObj.value("schoolData");
      QJsonArray schoolDataArray = schoolDataValue.toArray();
      for(int i = 0; i < schoolDataArray.size(); i++){
          QJsonObject obj = schoolDataArray.at(i).toObject();
          if(obj.value("schoolName").toString().compare("xiaoxue") == 0){
              obj["schoolCity"] = "Baoji";
              schoolDataArray.replace(i, obj);
              break;
          }
      }
      rootObj["schoolData"] = schoolDataArray;
    
      // 将json数据对象转为字符串
      QJsonDocument document;
      document.setObject(rootObj);
      QByteArray byJsonData = document.toJson(QJsonDocument::Compact);
      QString strJson(byJsonData);
    

新增json数据

• 原始json数据

  •   {
          "id":1002,
          "name":"Tom",
          "techData":["C++", "JAVA", "PYTHON"], 
          "schoolData":[
              {"schoolCity":"Xian","schoolName":"xiaoxue"},
              {"schoolCity":"Xian","schoolName":"zhongxue"},
              {"schoolCity":"Beijing","schoolName":"daxue"}
          ],
          "scoreData":{
              "Chinese":96,
              "English":82,
              "Math":90
          },
          "sex":true
      }
    

• 新增相应字段后的json数据

  •   {
          "class":5, // 新增项
          "home":{   // 新增项
              "father":52,
              "mather":52
          },
          "id":1002,
          "name":"Tom",
          "schoolData":[
              {"schoolCity":"Xian","schoolName":"xiaoxue"},
              {"schoolCity":"Xian","schoolName":"zhongxue"},
              {"schoolCity":"Beijing","schoolName":"daxue"},
              {"schoolCity":"shanghai","schoolName":"boshi"} // 新增项
          ],
          "scoreData":{
              "Chinese":96,
              "English":82,
              "Math":90,
              "Physics":100 // 新增项
          },
          "sex":true,
          "techData":["C++","JAVA","PYTHON","GO"] //新增GO数据
      }
    

• 代码

  •   QByteArray jsonData = "{\"id\":1002,\"name\":\"Tom\",\"techData\":[\"C++\",\"JAVA\",\"PYTHON\"], \"schoolData\":[{\"schoolCity\":\"Xian\",\"schoolName\":\"xiaoxue\"},{\"schoolCity\":\"Xian\",\"schoolName\":\"zhongxue\"},{\"schoolCity\":\"Beijing\",\"schoolName\":\"daxue\"}],\"scoreData\":{\"Chinese\":96,\"English\":82,\"Math\":90},\"sex\":true}";
    
      QJsonParseError result;
      QJsonDocument rootDoc = QJsonDocument::fromJson(jsonData, &result);
      if(rootDoc.isNull() || result.error != QJsonParseError::NoError){
          qDebug() << "parse json data failed.";
          return false;
      }
    
      QJsonObject rootObj = rootDoc.object();
    
      // 新增数据
      rootObj.insert("class", 5);
    
      // 新增数据对象
      QJsonObject homeObject;
      homeObject.insert("father", 52);
      homeObject.insert("mather", 52);
      rootObj.insert("home", homeObject);
    
      // 在数据对象中新增数据
      QJsonValue scoreDataValue = rootObj.value("scoreData");
      QJsonObject scoreDataObj = scoreDataValue.toObject();
      scoreDataObj.insert("Physics", 100);
      rootObj["scoreData"] = scoreDataObj;
    
      // 在数组中新增数据
      QJsonValue techDataValue = rootObj.value("techData");
      QJsonArray techDataArray = techDataValue.toArray();
      techDataArray.append("GO");
      rootObj["techData"] = techDataArray;
    
      // 在数组对象中新增数据
      QJsonValue schoolDataValue = rootObj.value("schoolData");
      QJsonArray schoolDataArray = schoolDataValue.toArray();
      QJsonObject doctorObj;
      doctorObj.insert("schoolName", "boshi");
      doctorObj.insert("schoolCity", "shanghai");
      schoolDataArray.append(doctorObj);
      rootObj["schoolData"] = schoolDataArray;
    
    
      QJsonDocument document;
      document.setObject(rootObj);
      QByteArray byJsonData = document.toJson(QJsonDocument::Compact);
      QString strJson(byJsonData);
    

删除json数据

• 原始json数据

  •   {
          "id":1002,
          "name":"Tom", //此项删除
          "techData":["C++","JAVA","PYTHON"], // PYTHON删除 
          "schoolData":[
              {"schoolCity":"Xian","schoolName":"xiaoxue"}, // 此项删除
              {"schoolCity":"Xian","schoolName":"zhongxue"},
              {"schoolCity":"Beijing","schoolName":"daxue"}
          ],
          "scoreData":{
              "Chinese":96, //此项删除
              "English":82,
              "Math":90
          },
          "sex":true
      }
    

• 删除相应字段后的json数据

  •   {
          "id":1002,
          "techData":["C++","JAVA"], 
          "schoolData":[
              {"schoolCity":"Xian","schoolName":"zhongxue"},
              {"schoolCity":"Beijing","schoolName":"daxue"}
          ],
          "scoreData":{
              "English":82,
              "Math":90
          },
          "sex":true
      }
    

• 代码

  •   QByteArray jsonData = "{\"id\":1002,\"name\":\"Tom\",\"techData\":[\"C++\",\"JAVA\",\"PYTHON\"], \"schoolData\":[{\"schoolCity\":\"Xian\",\"schoolName\":\"xiaoxue\"},{\"schoolCity\":\"Xian\",\"schoolName\":\"zhongxue\"},{\"schoolCity\":\"Beijing\",\"schoolName\":\"daxue\"}],\"scoreData\":{\"Chinese\":96,\"English\":82,\"Math\":90},\"sex\":true}";
    
      QJsonParseError result;
      QJsonDocument rootDoc = QJsonDocument::fromJson(jsonData, &result);
      if(rootDoc.isNull() || result.error != QJsonParseError::NoError){
          qDebug() << "rootdoc is null";
          return false;
      }
    
      QJsonObject rootObj = rootDoc.object();
    
      // 删除数据
      rootObj.remove("name");
    
      // 删除数据对象中的数据
      QJsonValue scoreDataValue = rootObj.value("scoreData");
      QJsonObject scoreDataObj = scoreDataValue.toObject();
      scoreDataObj.remove("Chinese");
      rootObj["scoreData"] = scoreDataObj;
    
    
      // 删除数组中的数据
      QJsonValue techDataValue = rootObj.value("techData");
      QJsonArray techDataArray = techDataValue.toArray();
      for(int i = 0; i < techDataArray.size(); i++){
          if(techDataArray.at(i).toString().compare("PYTHON") == 0){
              techDataArray.removeAt(i);
              break;
          }
      }
      rootObj["techData"] = techDataArray;
    
      // 删除数组对象中的数据
      QJsonValue schoolDataValue = rootObj.value("schoolData");
      QJsonArray schoolDataArray = schoolDataValue.toArray();
      for(int i = 0; i < schoolDataArray.size(); i++){
          QJsonObject obj = schoolDataArray.at(i).toObject();
          if(obj.value("schoolName").toString().compare("xiaoxue") == 0){
              schoolDataArray.removeAt(i);
              break;
          }
      }
      rootObj["schoolData"] = schoolDataArray;
    
    
      QJsonDocument document;
      document.setObject(rootObj);
      QByteArray byJsonData = document.toJson(QJsonDocument::Compact);
      QString strJson(byJsonData);