cJSON使用_创建及分析json

本文主要是介绍cJSON使用_创建及分析json，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

在前面简单介绍了cJSON相关的函数，下面建创建以及解析json数据。

1 创建

假如我们要创建如下的json数据

{"GET_WIFI":{"WIFI_COUNT" : 3,"WIFISSID":[{"SSID": "test_wifi01","SIGNAL": 99,"SECURITY": 0},{"SSID": "test_wifi02""SIGNAL": 88,"SECURITY": 1},{"SSID": "test_wifi03""SIGNAL": 77"SECURITY": 2}]}
}

代码如下：

#include <stdio.h>
#include "cJSON.h"typedef struct _SSID_INFO
{char ssid[32];int  signal;int security;
}SSID_INFO_S;int test_cjon_build()
{int ret = -1;SSID_INFO_S Info[3] = {{"test_wifi01",99,0},{"test_wifi02",88,1},{"test_wifi03",77,2}};cJSON* pHead = NULL;cJSON* pGetWifi = NULL;cJSON* pWifiCnt = NULL;cJSON* pWifiSsidArray = NULL;cJSON* pWifiSsid = NULL;cJSON* pSsid = NULL;cJSON* pSignal = NULL;cJSON* pSecurity = NULL;char* tmpBuff = NULL;int i = 0, cnt = 3;/* 创建json对象 */pHead = cJSON_CreateObject();if (NULL == pHead) goto end;/* 创建GET_WIFI对象并添加到头中 */pGetWifi = cJSON_CreateObject();if (NULL == pGetWifi) goto end;cJSON_AddItemToObject(pHead, "GET_WIFI", pGetWifi);/* 创建WIFI_COUNT并添加到GET_WIFI中 */pWifiCnt = cJSON_CreateNumber(cnt);if (NULL == pWifiCnt) goto end;cJSON_AddItemToObject(pGetWifi, "WIFI_COUNT", pWifiCnt);/* 创建WIFISSID数组 */pWifiSsidArray = cJSON_CreateArray(); if (NULL == pWifiSsidArray) goto end;cJSON_AddItemToObject(pGetWifi, "WIFISSID", pWifiSsidArray);for (i = 0; i < cnt; i++){/* 创建pWifiSsid对象并添加到WIFISSID数组中 */pWifiSsid = cJSON_CreateObject();if (NULL == pWifiSsid) goto end;cJSON_AddItemToArray(pWifiSsidArray,pWifiSsid);/* 将各个值添加到pWifiSsid对象中 */pSsid = cJSON_CreateString(Info[i].ssid);if (NULL == pSsid) goto end;cJSON_AddItemToObject(pWifiSsid, "SSID", pSsid);pSignal = cJSON_CreateNumber(Info[i].signal);if (NULL == pSignal) goto end;cJSON_AddItemToObject(pWifiSsid, "SIGNAL", pSignal);pSecurity = cJSON_CreateNumber(Info[i].security);if (NULL == pSecurity) goto end;cJSON_AddItemToObject(pWifiSsid, "SECURITY", pSecurity);}/* 输出为字符串形式 */tmpBuff = cJSON_Print(pHead);if (NULL == tmpBuff) goto end;printf("tmpBuff:%s\n",tmpBuff);/*tmpBuff:{"GET_WIFI":	{"WIFI_COUNT":	3,"WIFISSID":	[{"SSID":	"test_wifi01","SIGNAL":	99,"SECURITY":	0}, {"SSID":	"test_wifi02","SIGNAL":	88,"SECURITY":	1}, {"SSID":	"test_wifi03","SIGNAL":	77,"SECURITY":	2}]}
}*/ret = 0;end:/* 释放内存 */cJSON_Delete(pHead);if (NULL != tmpBuff) free(tmpBuff);return ret;
}

2 解析

对上面的数据进行解析，代码如下：

#include <stdio.h>
#include "cJSON.h"#define TEST_STRING "{" \"\"GET_WIFI\":" \"{" \"\"WIFI_COUNT\" : 3," \"\"WIFISSID\":[" \"{" \"\"SSID\": \"test_wifi01\"," \"\"SIGNAL\": 99," \"\"SECURITY\": 0" \"}," \"{" \"\"SSID\": \"test_wifi02\"," \"\"SIGNAL\": 88," \"\"SECURITY\": 1" \"}," \"{" \"\"SSID\": \"test_wifi03\"," \"\"SIGNAL\": 77," \"\"SECURITY\": 2" \"}" \"]" \"}" \
"}"int test_cjon_parse()
{int ret = -1;char* error = NULL;int cnt = 0, i = 0;cJSON* pHead = NULL;cJSON* pGetWifi = NULL;cJSON* pWifiCnt = NULL;cJSON* pWifiSsidArray = NULL;cJSON* pWifiSsid = NULL;cJSON* pSsid = NULL;cJSON* pSignal = NULL;cJSON* pSecurity = NULL;pHead = cJSON_Parse(TEST_STRING);if (NULL == pHead){error = cJSON_GetErrorPtr();if (NULL != error)printf("error:%s\n", error);goto end;}pGetWifi = cJSON_GetObjectItem(pHead, "GET_WIFI");if (NULL == pGetWifi) goto end;pWifiCnt = cJSON_GetObjectItem(pGetWifi, "WIFI_COUNT");if (NULL == pWifiCnt) goto end;cnt = pWifiCnt->valuedouble;pWifiSsidArray = cJSON_GetObjectItem(pGetWifi, "WIFISSID");if (NULL == pWifiSsidArray) goto end;cJSON_ArrayForEach(pWifiSsid, pWifiSsidArray){pSsid = cJSON_GetObjectItem(pWifiSsid, "SSID");pSignal = cJSON_GetObjectItem(pWifiSsid, "SIGNAL");pSecurity = cJSON_GetObjectItem(pWifiSsid, "SECURITY");printf("total wifi num:%d, current num:%d, wifi ssid:%s, wifi signal:%d, wifi security:%d\n",cnt, ++i, pSsid->valuestring, (int)pSignal->valuedouble, (int)pSecurity->valuedouble);}ret = 0;end:/* 释放内存 */cJSON_Delete(pHead);return ret;
}

输出结果如下：

total wifi num:3, current num:1, wifi ssid:test_wifi01, wifi signal:99, wifi security:0
total wifi num:3, current num:2, wifi ssid:test_wifi02, wifi signal:88, wifi security:1
total wifi num:3, current num:3, wifi ssid:test_wifi03, wifi signal:77, wifi security:2

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