linuxc语言全面学习json解析函数

{{linuxc语言全面学习json解析函数json结构的定义typedefstructcJSON{//cJSON结构体{{structcJSON*next,*prev;/*遍历数组或对象链的前向或后向链表指针7{{structcJSON*child;inttype;char*valuestring;intvalueint;doublevaluedouble;char*string;structcJSON*child;inttype;char*valuestring;intvalueint;doublevaluedouble;char*string;}cJSON;/*key的类型*//*字符串值*//*整数值*//*浮点数值*//*key的名字*/json常用函数说明(1)定义一个JSON数据包，按照cJSON结构体的结构序列化整个数据包，并在堆中申请空间，返回值是成功返回一个指向内存块中的tJSON的指针，失败返回NULLcJSON*cJSON_Parse(constchar*value);获取JSON字符串字段值cJSON*cJSON_GetObjectItem(cJSON*object,constchar*string);向对象中增加(字符)节点cJSON_AddStringToObject(root,"名称","字符串”)；向对象中增加对象(字符串、数组、数字)cJSON_AddStringToObject(pJsonRoot,"hello","helloworld");/添加字符串cJSON_AddNumberToObject(pJsonRoot,"number",10010);//添加数字cJSON_AddBoolToObject(pJsonRoot,"bool",1);//添加bool值cJSON_AddItemToObject(root,"名称",cJSON_CreateString(”邙东宇"));//添加对象cJSON_AddItemToObject(root,"名称",cJSON_CreateNumber(100));获取数组成员对象个数intcJSON_GetArraySize(cJSON*array);获取数组元素cJSON*tmp=cJSON_GetArrayItem(array,1);//下标从0开始</span>函数应用举例：将下面的数据用json解析打印出来:"name":"helloworld","number":10010,"bool":true,"subobj":{}"分析：obj_1:helloworldobj_2:10010obj_3:1sub_obj_1:middle代码如下：#include<stdio.h>#include"cJSON.h"char*makeJson()

cJSON*pJsonRoot=NULL;pJsonRoot=cJSON_CreateObject();if(NULL==pJsonRoot){//errorhappendherereturnNULL;}cJSON_AddStringToObject(pJsonRoot,"name","helloworld");cJSON_AddNumberToObject(pJsonRoot,"number",10010);cJSON_AddBoolToObject(pJsonRoot,"bool",1);cJSON*pSubJson=NULL;pSubJson=cJSON_CreateObject();if(NULL==pSubJson){//createobjectfaild,exitcJSON_Delete(pJsonRoot);returnNULL;}cJSON_AddStringToObject(pSubJson,"level","middle");cJSON_AddItemToObject(pJsonRoot,"subobj",pSubJson);char*p=cJSON_Print(pJsonRoot);//elseuse://char*p=cJSON_PrintUnformatted(pJsonRoot);if(NULL==p){//convertjsonlisttostringfaild,exit//becausesubjsonpSubJsonhanbeenaddtopJsonRoot,sojustdeletepJsonRoot,ifyoualsodeletepSubJson,itwillcoredump,anderroris:doublefreecJSON_Delete(pJsonRoot);returnNULL;}//free(p);cJSON_Delete(pJsonRoot);returnp;}voidparseJson(char*pMsg){if(NULL==pMsg){return;}cJSON*pJson=cJSON_Parse(pMsg);if(NULL==pJson){//parsefaild,returnreturn;}//getstringfromjsoncJSON*pSub=cJSON_GetObjectItem(pJson,"name");if(NULL==pSub){//getobjectnamed"hello"faild}printf("obj_1:%s\n",pSub->valuestring);//getnumberfromjsonpSub=cJSON_GetObjectItem(pJson,"number");if(NULL==pSub){

//getnumberfromjsonfaild}printf("obj_2:%d\n",pSub->valueint);//getboolfromjsonpSub=cJSON_GetObjectItem(pJson,"bool");if(NULL==pSub){//getboolfromjsonfaild}printf("obj_3:%d\n",pSub->valueint);//getsubobjectpSub=cJSON_GetObjectItem(pJson,"subobj");if(NULL==pSub){//getsubobjectfaild}cJSON*pSubSub=cJSON_GetObjectItem(pSub,"level");if(NULL==pSubSub){//getobjectfromsubjectobjectfaild}printf("sub_obj_1:%s\n",pSubSub->valuestring);cJSON_Delete(pJson);}intmain(){char*p=makeJso