http://www.cnblogs.com/Pan-Z/p/6425602.html

1，cJSON支持在C程序中创建和解析JSON数据，其提供多种方法供C程序使用，最直接的是将cJSON.c和cJSON.h加入到C工程中，源代码：https://github.com/DaveGamble/cJSON

2, QJsonObject用于在Qt中创建JSON对象

3，数据传输通过UDP运行

Qt代码如下：

首先在PRo文件中加入

QT += network

h文件内容：

#ifndef MAINWINDOW_H#define MAINWINDOW_H#include <QMainWindow>#include<QtNetwork>namespace Ui {class MainWindow;}class MainWindow : public QMainWindow{    Q_OBJECTpublic:    explicit MainWindow(QWidget *parent = 0);    ~MainWindow();     QUdpSocket *sender;    QByteArray byteArray;private slots:     void on_pushButton_clicked();private:    Ui::MainWindow *ui;};#endif // MAINWINDOW_H
cpp文件内容：
#include "mainwindow.h"#include "ui_mainwindow.h"#include<QJsonObject>#include<QJsonDocument>#include<QDebug>MainWindow::MainWindow(QWidget *parent) :    QMainWindow(parent),    ui(new Ui::MainWindow){    ui->setupUi(this);    sender = new QUdpSocket(this);    QJsonObject rectJson;    rectJson.insert("Type","Rectangle");    rectJson.insert("height",42);    rectJson.insert("widght",23);    QJsonDocument rectJsonDoc;    rectJsonDoc.setObject(rectJson);     byteArray = rectJsonDoc.toJson(QJsonDocument::Compact);}MainWindow::~MainWindow(){    delete ui;}void MainWindow::on_pushButton_clicked(){     QHostAddress address;     address.setAddress(QString("192.168.230.140"));       sender->writeDatagram(byteArray.data(),byteArray.size(),                            address,4444);}
Qt程序通过端口4444，向ip为192.168.230.140的主机发送JSON数据
4，C程序如下：
{    int sock_fd;    char rcv_buff[512];    struct sockaddr_in client_addr;    struct sockaddr_in server_addr;    int client_len;    int rcv_num = -1;    if ((sock_fd = socket(AF_INET, SOCK_DGRAM,0)) < 0)    {        perror("socket create error/n");        exit(1);    }    memset(&server_addr,0,sizeof(struct sockaddr_in));        server_addr.sin_family = AF_INET;    server_addr.sin_port = htons(4444);    server_addr.sin_addr.s_addr = htonl(INADDR_ANY);    client_len = sizeof(struct sockaddr_in);    if (bind(sock_fd, (struct sockaddr *)&server_addr, sizeof(struct sockaddr_in)) < 0)    {        perror("bind socket error./n");        exit(1);    }        while (1)    {        /*zero the buff of rvbsm and hvbsm? zhp*/                    rcv_num= recvfrom(sock_fd, rcv_buff, sizeof(rcv_buff), 0, (struct sockaddr*)&client_addr, &client_len);        if (rcv_num>0)        {                    rcv_buff[rcv_num] = '/0';                    printf("rx bsm num = %d/n",rcv_num);                    //printf();                        printf("%s %u says: %s/n",inet_ntoa(client_addr.sin_addr),ntohs(client_addr.sin_port),rcv_buff);                      //parse_UDP_data(rcv_num,rcv_buff);                    if(rcv_buff != NULL)                        {                            cJSON* pJson = cJSON_Parse(rcv_buff);                            if(pJson == NULL)                                {                                    printf("Json Parse failed./n");                                    return 0;                                }                            cJSON* pSub1 = cJSON_GetObjectItem(pJson,"Type");                            cJSON* pSub2 = cJSON_GetObjectItem(pJson,"height");                            cJSON* pSub3 = cJSON_GetObjectItem(pJson,"widght");                            if(pSub1!=NULL)                                {                                    printf("Type : %s/n", pSub1->valuestring);                                }                            if(pSub2!=NULL)                                {                                    printf("height : %d/n", pSub2->valueint);                                }                            if(pSub3!=NULL)                                {                                    printf("widght : %d/n", pSub3->valueint);                                }                        }                            }        else        {            perror("recv BSM error/n");            break;        }    }    close(sock_fd);   }
编译C程序:gcc -I. -lm -o rencode *.c
由于cJSON使用了标准数学库，所以在编译中需链接其库文件-lm；
在IP为192.168.230.140的linux服务器中执行./rencode
输出结果为：