jsoncpp的安装与使用示例

安装：

生成静态库

生成静态库:
第一步:生成目标文件:
g++ -g -Wall -c json_reader.cpp json_value.cpp json_writer.cpp -I. -I../../include -lpthread

会生成三个*.o文件
 json_reader.o
json_value.o
json_writer.o

第二步:生成静态库文件:
ar rcs libjsoncpp.a *.o

生成动态库:

g++ -g json_reader.cpp json_value.cpp json_writer.cpp -fPIC -Wall -shared -o libjsoncpp.so -I. -I../../include -lpthread

记得引用时:

1.指定库文件:比如将生成的 libjsoncpp.so和libjsoncpp.a库文件放到/usr/local/lib/jsoncpp-src-0.5.0/下面.

2.指定头文件位置:比如,将jsoncpp-src-0.5.0/include/下的头文件放到/usr/local/include/jsoncpp-src-0.5.0/下面.

 

 实用示例：

#include <iostream>
#include <fstream>

//#include </usr/local/include/jsoncpp0.5.0/json/json.h>
//#include <json/json.h>
#include <json/json.h>
using namespace std;

int main()
{
    //根节点
    Json::Value root;

    //根节点属性
    root["name"] = Json::Value("Tsybius");
    root["age"] = Json::Value(23);
    root["sex_is_male"] = Json::Value(true);

    //子节点
    Json::Value partner;

    //子节点属性
    partner["partner_name"] = Json::Value("Galatea");
    partner["partner_age"] = Json::Value(21);
    partner["partner_sex_is_male"] = Json::Value(false);

    //子节点挂到根节点上
    root["partner"] = Json::Value(partner);

    //数组形式
    root["achievement"].append("ach1");
    root["achievement"].append("ach2");
    root["achievement"].append("ach3");

    //直接输出
    cout << "FastWriter:" << endl;
    Json::FastWriter fw;
    cout << fw.write(root) << endl << endl;

    //缩进输出
    cout << "StyledWriter:" << endl;
    Json::StyledWriter sw;
    cout << sw.write(root) << endl << endl;

    //输出到文件
    ofstream os;
    os.open("./PersonalInfo.js");
    os << sw.write(root);
    os.close();

    return 0;
}

output:

FastWriter:
{"achievement":["ach1","ach2","ach3"],"age":23,"name":"Tsybius","partner":{"partner_age":21,"partner_name":"Galatea","partner_sex_is_male":false},"sex_is_male":true}


StyledWriter:
{
   "achievement" : [ "ach1", "ach2", "ach3" ],
   "age" : 23,
   "name" : "Tsybius",
   "partner" : {
      "partner_age" : 21,
      "partner_name" : "Galatea",
      "partner_sex_is_male" : false
   },
   "sex_is_male" : true
}

 

#include <bits/stdc++.h>
//#include <json/json.h>
#include </usr/include/jsoncpp/json/json.h>
void readJson();
void writeJson();

int main(int argc, char **argv)
{
    readJson();
    writeJson();
    return 0;
}

void readJson()
{
    using namespace std;
    std::string strValue =
        "{\"name\":\"json\",\"array\":[{\"cpp\":\"jsoncpp\"},{\"java\":\"jsoninjava\"},{\"php\":\"support\"}]}";

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

    if (reader.parse(strValue, value)) {
        std::string out = value["name"].asString();
        std::cout << out << std::endl;
        const Json::Value arrayObj = value["array"];
        for (unsigned int i = 0; i < arrayObj.size(); i++) {
            if (!arrayObj[i].isMember("cpp"))
                continue;
            out = arrayObj[i]["cpp"].asString();
            std::cout << out;
            if (i != (arrayObj.size() - 1))
                std::cout << std::endl;
        }
    }
}

void writeJson()
{
    using namespace std;

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

    item["cpp"] = "jsoncpp";
    item["java"] = "jsoninjava";
    item["php"] = "support";
    arrayObj.append(item);

    root["name"] = "json";
    root["array"] = arrayObj;

    root.toStyledString();
    std::string out = root.toStyledString();
    std::cout << out << std::endl;
}

json
jsoncpp
{
   "array" : [
      {
         "cpp" : "jsoncpp",
         "java" : "jsoninjava",
         "php" : "support"
      }
   ],
   "name" : "json"
}