C++ JSON

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目录

[TOC]

安装（Windows）

1、下载 : https://codeload.github.com/open-source-parsers/jsoncpp/zip/refs/tags/1.9.3

2、VSCode 打开项目，直接Cmake编译项目

3、得到libjsoncpp.a文件

4、新建项目就可以使用json了

项目配置

VS 项目配置g++

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{
    "label": "build demo_json",
    "type": "shell",
    "command": "g++",
    "args": [
        "-g", 
        "${workspaceFolder}/demo_json.cpp",
        // "-I", "D:/Tools/cplus_relate/eigen-3.4.0/Eigen/",
        "-I", "${workspaceFolder}/include/",
        "-L", "${workspaceFolder}/libs/",
        "-l", "jsoncpp",
        "-o", "main.exe",
        ],
    "group": {
        "kind": "build",
        "isDefault": true
    },
    "dependsOn":[
        "clear",
    ],
},

CMake 配置

使用

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 int ReadJson(const std::string & strValue) 
 {
     using namespace std;

     Json::Reader reader;
     Json::Value value;

     if (reader.parse(strValue, value))
     {
         //解析json中的对象
         string out = value["name"].asString();
         cout << "name : "   << out << endl;
         cout << "number : " << value["number"].asInt() << endl;
         cout << "value : "  << value["value"].asBool() << endl;
         cout << "no such num : " << value["haha"].asInt() << endl;
         cout << "no such str : " << value["hehe"].asString() << endl;

         //解析数组对象
         const Json::Value arrayNum = value["arrnum"];
         for (unsigned int i = 0; i < arrayNum.size(); i++)
         {
             cout << "arrnum[" << i << "] = " << arrayNum[i];
         }
         //解析对象数组对象
         Json::Value arrayObj = value["array"];
         cout << "array size = " << arrayObj.size() << endl;
         for(unsigned int i = 0; i < arrayObj.size(); i++)
         {
             cout << arrayObj[i];
         }
         //从对象数组中找到想要的对象
         for(unsigned int i = 0; i < arrayObj.size(); i++)
         {
             if (arrayObj[i].isMember("string")) 
             {
                 out = arrayObj[i]["string"].asString();
                 std::cout << "string : " << out << std::endl;
             }
         }
     }

     return 0;
 }

 std::string writeJson() 
 {
     using namespace std;

     Json::Value root;
     Json::Value arrayObj;
     Json::Value item;
     Json::Value iNum;

     item["string"]    = "this is a string";
     item["number"]    = 999;
     item["aaaaaa"]    = "bbbbbb";
     arrayObj.append(item);

     //直接对jsoncpp对象以数字索引作为下标进行赋值，则自动作为数组
     iNum[1] = 1;
     iNum[2] = 2;
     iNum[3] = 3;
     iNum[4] = 4;
     iNum[5] = 5;
     iNum[6] = 6;

     //增加对象数组
     root["array"]    = arrayObj;
     //增加字符串
     root["name"]    = "json";
     //增加数字
     root["number"]    = 666;
     //增加布尔变量
     root["value"]    = true;
     //增加数字数组
     root["arrnum"]    = iNum;

     root.toStyledString();
     string out = root.toStyledString();

     return out;
 }
// ref:: http://t.zoukankan.com/fengbohello-p-4066254.html

配置

VScode 配置 svn_LDG1998的博客-CSDN博客_vscode配置svn