linux下使用JSON传输数据

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我是靠谱客的博主寂寞战斗机，最近开发中收集的这篇文章主要介绍linux下使用JSON传输数据，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

一.在Linux下安装json库

想要在Linux上方便的使用json，需要在linux上安装json库

1）首先先下载json库压缩包，照着链接里的说明安装即可。

链接：https://pan.baidu.com/s/1QsXeBa9cWtYthxkfPZKvkw
提取码：bkop

二.安装步骤：

   1.拷贝并解压到ubuntu系统 json-c-0.9.tar.gz
       命令： tar xvf json-c-0.9.tar.gz
   2.执行安装命令
       命令： ./configure
           make
           sudo make install

三.json函数介绍

json: 为了避免不同平台下的字节对齐、类型大小不统一的问题，json库把数据封装成具有一定格式的字符流数据，进行传输。

json格式：把数据与键值一一对应，数据传输双方约定好同一键值，

使用接口API根据键值操作jason对象（jason_object）存储或取得数据。

一般使用：

数据-》（封装）jason对象-》String格式-》。。。传输。。。-》String格式-》（解析）jason对象-》取得数据

(int、char..)数据，与键值成对存入json对象—————————————————————————————————>通过键值从json对象取得数据

json接口API（注意：在json中所有数据类型（arry、int、string、char）都是一个jason对象）

1、数据的封装（单对象（int、char、string）和数组（arry））

(1)新建对象：

A.创建一个Json对象：

struct json_object * json_object_new_object (void)

B.创建一个Json数组对象：

struct json_object * json_object_new_array (void)

C.销毁json对象

void json_object_put (struct json_object *obj)

(2)json对象的转换（普通类型->json对象）：

1：struct json_object * json_object_new_int (int i)

2：struct json_object * json_object_new_double (double d)

3：struct json_object * json_object_new_string (const char *s)

4：struct json_object * json_object_new_boolean (boolean b)

5：struct json_object * json_object_new_string_len (const char *s, int len)

(3)json对象的处理

A.普通对象

添加：void json_object_object_add (struct json_object *obj, const char *key, struct json_object *val)

删除：void json_object_object_del (struct json_object *obj, const char *key)

查询：struct json_object * json_object_object_get (struct json_object *obj, const char *key)

根据key获取：struct json_object * json_object_object_get (struct json_object *obj, const char *key)

B.数组对象

获取长度：int json_object_array_length (struct json_object *obj)

添加：int json_object_array_add (struct json_object *obj, struct json_object *val)

指定位置添加：int json_object_array_put_idx (struct json_object *obj, int idx, struct json_object *val)

获取指定位置对象：struct json_object * json_object_array_get_idx (struct json_object *obj, int idx)

（4）json_object To 字符流

const char * json_object_to_json_string (struct json_object *obj)

1、数据的解析（解析获取到的json格式字符流）

（1）字符流 To json_object

struct json_object* json_tokener_parse(const char *str)

（2）对象获取

A.普通对象

根据key获取：struct json_object * json_object_object_get (struct json_object *obj, const char *key)

B.数组对象

获取指定位置对象：struct json_object * json_object_array_get_idx (struct json_object *obj, int idx)

（3）对象的转换（数据还原）

bool型：boolean json_object_get_boolean (struct json_object *obj)

double型：double json_object_get_double (struct json_object *obj)

整型：int json_object_get_int (struct json_object *obj)

字符数组：const char * json_object_get_string (struct json_object *obj)

四、接下条通过简单例子介绍下

1.json函数封装

#include "myhead.h"
//传cmd和结构体进去返回一个json打包好的buf
char *pack_json(char *cmd,data mydata)
{
char *data_buf = (char *)malloc(512);
//1、创建一个json数组对象，就可以理解为外面那个大容器[]
struct json_object *arr=json_object_new_array();
//2、创建两个字符串对象，可以以理解为[]中的两个小容器{}
struct json_object *str1=json_object_new_object();
struct json_object *str2=json_object_new_object();
//3、把要存放的数据转为对象
struct json_object *value0=json_object_new_string(cmd);
struct json_object *value1=json_object_new_string(mydata.username);
struct json_object *value2=json_object_new_string(mydata.userpasswd);
struct json_object *value3=json_object_new_string(mydata.devid);
struct json_object *value4=json_object_new_string(mydata.superpasswd);
struct json_object *value5=json_object_new_string(mydata.time_passwd);
struct json_object *value6=json_object_new_string(mydata.fingerid);
struct json_object *value7=json_object_new_int(mydata.flag);
struct json_object *value8=json_object_new_string(mydata.phone);
struct json_object *value9=json_object_new_string(mydata.dev_name);
//4、把数值对象添加到字符串对象中
json_object_object_add(str1,"cmd", value0);
json_object_object_add(str2,"username", value1);
json_object_object_add(str2,"userpasswd", value2);
json_object_object_add(str2,"devid", value3);
json_object_object_add(str2,"superpasswd", value4);
json_object_object_add(str2,"time_passwd", value5);
json_object_object_add(str2,"fingerid", value6);
json_object_object_add(str2,"flag", value7);
json_object_object_add(str2,"phone", value8);
json_object_object_add(str2,"dev_name", value9);
//5、把字符串对象添加到数组对象中
json_object_array_add(arr,str1);
json_object_array_add(arr,str2);
//6、把数组对象转为字符流进行发送
const char *temp=json_object_to_json_string(arr);
bzero(data_buf,sizeof(data_buf));
strcpy(data_buf,temp);
printf("%sn",temp);
return data_buf;
}
//将收到的buf解包成cmd
char *get_cmd(char *buf)
{
char *cmd_buf=(char *)malloc(10);
//1、把得到的字符流转为数组对象
struct json_object *arr=json_tokener_parse(buf);
//2、获取数组指定位置的对象
struct json_object *str1=json_object_array_get_idx(arr,0);
//3、在字符串｛｝对象中根据key值找到数值对象
struct json_object *value1=json_object_object_get(str1,"cmd");
//4、数值对象转换为对应的数值
const char *temp = json_object_get_string(value1);
//bzero(cam_buf,sizeof(cmd_buf));
strcpy(cmd_buf,temp);
return cmd_buf;
}
//将收到的jsonbuf返回一个结构体
data *get_struct(char *buf)
{
data *mydata = (data *)malloc(sizeof(data));
//1、把得到的字符流转为数组对象
struct json_object *arr=json_tokener_parse(buf);
//2、获取数组指定位置的对象
struct json_object *str1=json_object_array_get_idx(arr,1);
//3、在字符串｛｝对象中根据key值找到数值对象
struct json_object *value1=json_object_object_get(str1,"username");
struct json_object *value2=json_object_object_get(str1,"userpasswd");
struct json_object *value3=json_object_object_get(str1,"devid");
struct json_object *value4=json_object_object_get(str1,"superpasswd");
struct json_object *value5=json_object_object_get(str1,"time_passwd");
struct json_object *value6=json_object_object_get(str1,"fingerid");
struct json_object *value7=json_object_object_get(str1,"flag");
struct json_object *value8=json_object_object_get(str1,"phone");
struct json_object *value9=json_object_object_get(str1,"dev_name");
//4、数值对象转换为对应的数值
const char *temp1 = json_object_get_string(value1);
const char *temp2 = json_object_get_string(value2);
const char *temp3 = json_object_get_string(value3);
const char *temp4 = json_object_get_string(value4);
const char *temp5 = json_object_get_string(value5);
const char *temp6 = json_object_get_string(value6);
const int temp7 = json_object_get_int(value7);
const char *temp8 = json_object_get_string(value8);
const char *temp9 = json_object_get_string(value9);
strcpy(mydata->username,temp1);
strcpy(mydata->userpasswd,temp2);
strcpy(mydata->devid,temp3);
strcpy(mydata->superpasswd,temp4);
strcpy(mydata->time_passwd,temp5);
strcpy(mydata->fingerid,temp6);
mydata->flag = temp7;
strcpy(mydata->phone,temp8);
strcpy(mydata->dev_name,temp9);
return mydata;
}

2.客户端编写

#include "myhead.h"
#define PORT 31415
#define IP_ADDR
"192.168.5.188"
int main(int argc, char const *argv[])
{
int fd = socket(AF_INET,SOCK_STREAM,0);
char cmd[10] = "d100";
char buf[512];
struct sockaddr_in server;
server.sin_family = AF_INET;
server.sin_port =htons(PORT);
server.sin_addr.s_addr = inet_addr(IP_ADDR);
int ret = connect(fd,(struct sockaddr *)(&server),sizeof(server));
if(ret < 0){
printf("connect error!!!n");
perror("connect");
return 0;
}else{
printf("success！n");
}
data mydata = {
.username = "hhhhhhh",
.userpasswd = "pppppp",
.devid = "ppqpqpq",
.superpasswd = "oooo",
.time_passwd = "1234",
.fingerid = "iooo",
.flag = 1,
.phone = "1008610000",
.dev_name = "haib",
};
bzero(buf,sizeof(buf));
strcpy(buf,pack_json(cmd,mydata));
printf("buf=%sn",buf );
send(fd,buf,strlen(buf),0);
return 0;
}

3.服务器端编写

#include "myhead.h"
#define PORT 31415
#define IP_ADDR
"192.168.5.188"
int main(int argc, char const *argv[])
{
int fd = socket(AF_INET,SOCK_STREAM,0);
int on=1;
char buf[512];
char cmd[10];
setsockopt(fd,SOL_SOCKET,SO_REUSEADDR,&on,sizeof(on));
struct sockaddr_in server; //定义一个结构体用来描述服务器
server.sin_family=AF_INET;
server.sin_port = htons(PORT);
server.sin_addr.s_addr = inet_addr(IP_ADDR);
int ret = bind(fd,(struct sockaddr *)(&server),sizeof(server));
if(ret == -1){
printf("绑定服务器失败！n");
perror("bind");
exit(1);
}else
printf("绑定服务器成功！n");
listen(fd,10);
struct sockaddr_in client;
int length = sizeof(client);
int newfd = accept(fd,(struct sockaddr *)(&client),&length);
printf("客户端%d已连接，IP:%s
主机号：%dn",newfd,inet_ntoa(client.sin_addr),ntohs(client.sin_port));
recv(newfd,buf,sizeof(buf),0);
printf("buf=%sn", buf);
bzero(cmd,sizeof(cmd));
strcpy(cmd,get_cmd(buf));
printf("cmd=%sn",cmd);
data *test = get_struct(buf);
printf("suername = %sn",test->username);
printf("superpasswd = %sn",test->userpasswd);
printf("devid=%sn",test->devid);
return 0;
}

4.头文件（有些多余的头文件~懒得删了）

#ifndef _MYHEAD_H
#define _MYHEAD_H
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <stdlib.h>
#include <strings.h>
#include <pthread.h>
#include "/usr/local/include/json/json.h"
typedef struct Data{
char username[20];
//用户名
char userpasswd[20];
//用户密码
char devid[20];
// 设备ID-->设备一联网就发送设备ID和超级密码
char superpasswd[20];
//设备超级密码
char time_passwd[20];	//设备开锁临时密码
char fingerid[20];
//指纹ID编号
int
flag;
//返回值，返回0表示操作失败，返回1表示操作成功
char phone[20];
//应急电话号码
char dev_name[20];
//用户自定义的设备名，与设备ID对应
}data;
extern char *pack_json(char *cmd,data mydata);
extern char *get_cmd(char *buf);
extern data *get_struct(char *buf);
#endif

5.用GCC编译

gcc server.c json_fun.c -o server -ljson

gcc client.c json_fun.c -o client -ljson

运行结果

绑定服务器成功！
客户端4已连接，IP:192.168.5.188 主机号：50306
buf=[ { "cmd": "d100" }, { "username": "hhhhhhh", "userpasswd": "pppppp", "devid": "ppqpqpq", "superpasswd": "oooo", "time_passwd": "1234", "fingerid": "iooo", "flag": 1, "phone": "1008610000", "dev_name": "haib" } ]
cmd=d100
suername = hhhhhhh
superpasswd = pppppp
devid=ppqpqpq
--------------------------------------------------------------------------------------------------

success！
[ { "cmd": "d100" }, { "username": "hhhhhhh", "userpasswd": "pppppp", "devid": "ppqpqpq", "superpasswd": "oooo", "time_passwd": "1234", "fingerid": "iooo", "flag": 1, "phone": "1008610000", "dev_name": "haib" } ]
buf=[ { "cmd": "d100" }, { "username": "hhhhhhh", "userpasswd": "pppppp", "devid": "ppqpqpq", "superpasswd": "oooo", "time_passwd": "1234", "fingerid": "iooo", "flag": 1, "phone": "1008610000", "dev_name": "haib" } ]

运行的时候遇到一个问题，就是会报找不到动态库libjson.so.0,解决方法是：