共分两个部分，1)创建json、2)解析json

1)创建嵌套json的代码

char * makeJson()

{

cJSON * pRoot = NULL;

cJSON * pSub_1 = NULL;

cJSON * pSub_2 = NULL;

if((pRoot = cJSON_CreateObject()) == NULL)

{

return NULL;

}

if((pSub_1 = cJSON_CreateObject()) == NULL)

{

return NULL;

}

if((pSub_2 = cJSON_CreateObject()) == NULL)

{

return NULL;

}

cJSON_AddStringToObject(pSub_2, "cStr", "ccccccc");

cJSON_AddStringToObject(pSub_1, "bStr", "bbbbbbb");

cJSON_AddItemToObject(pSub_1, "subobject_2", pSub_2);

cJSON_AddStringToObject(pRoot, "aStr", "aaaaaaa");

cJSON_AddItemToObject(pRoot, "subobject_1", pSub_1);

cJSON_AddStringToObject(pRoot, "xStr", "xxxxxxx");

//cJSON_PrintUnformatted : make json string for Unformatted

//char * pJson = cJSON_PrintUnformatted(pRoot);

char * pJson = cJSON_Print(pRoot);

if(NULL == pJson)

{

cJSON_Delete(pRoot);

return NULL;

}

return pJson;

}

2)解析json的代码

int parseJson(const char * pJson)

{

if(NULL == pJson)

{

return 1;

}

cJSON * pRoot = cJSON_Parse(pJson);

if(NULL == pRoot)

{

return 2;

}

cJSON * pSub_1 = cJSON_GetObjectItem(pRoot, "aStr");

if(NULL == pSub_1)

{

cJSON_Delete(pRoot);

return 3;

}

printf("get aStr : [%s]\n", pSub_1->valuestring);

pSub_1 = cJSON_GetObjectItem(pRoot, "xStr");

if(NULL == pSub_1)

{

cJSON_Delete(pRoot);

return 4;

}

printf("get xStr : [%s]\n", pSub_1->valuestring);

pSub_1 = cJSON_GetObjectItem(pRoot, "subobject_1");

if(NULL == pSub_1)

{

cJSON_Delete(pRoot);

return 5;

}

printf("get Sub Obj 1\n");

cJSON * pSub_2 = cJSON_GetObjectItem(pSub_1, "bStr");

if(NULL == pSub_2)

{

cJSON_Delete(pRoot);

return 6;

}

printf("get bStr : [%s]\n", pSub_2->valuestring);

pSub_2 = cJSON_GetObjectItem(pSub_1, "subobject_2");

if(NULL == pSub_2)

{

cJSON_Delete(pRoot);

return 7;

}

printf("get Obj 2\n");

cJSON * pStr = cJSON_GetObjectItem(pSub_2, "cStr");

if(NULL == pStr)

{

cJSON_Delete(pRoot);

return 8;

}

printf("get cStr : [%s]\n", pStr->valuestring);

cJSON_Delete(pRoot);

return 0;

}

3)主函数

int main()

{

char * pJson = makeJson();

printf("JSON:\n%s\n", pJson);

parseJson(pJson);

free(pJson);

return 0;

}

#include

#include "cJSON.h"

char * makeJson()

{

cJSON * pRoot = NULL;

cJSON * pSub_1 = NULL;

cJSON * pSub_2 = NULL;

if((pRoot = cJSON_CreateObject()) == NULL)

{

return NULL;

}

if((pSub_1 = cJSON_CreateObject()) == NULL)

{

return NULL;

}

if((pSub_2 = cJSON_CreateObject()) == NULL)

{

return NULL;

}

cJSON_AddStringToObject(pSub_2, "cStr", "ccccccc");

cJSON_AddStringToObject(pSub_1, "bStr", "bbbbbbb");

cJSON_AddItemToObject(pSub_1, "subobject_2", pSub_2);

cJSON_AddStringToObject(pRoot, "aStr", "aaaaaaa");

cJSON_AddItemToObject(pRoot, "subobject_1", pSub_1);

cJSON_AddStringToObject(pRoot, "xStr", "xxxxxxx");

//cJSON_PrintUnformatted : make json string for Unformatted

//char * pJson = cJSON_PrintUnformatted(pRoot);

char * pJson = cJSON_Print(pRoot);

if(NULL == pJson)

{

cJSON_Delete(pRoot);

return NULL;

}

return pJson;

}

int parseJson(const char * pJson)

{

if(NULL == pJson)

{

return 1;

}

cJSON * pRoot = cJSON_Parse(pJson);

if(NULL == pRoot)

{

return 2;

}

cJSON * pSub_1 = cJSON_GetObjectItem(pRoot, "aStr");

if(NULL == pSub_1)

{

cJSON_Delete(pRoot);

return 3;

}

printf("get aStr : [%s]\n", pSub_1->valuestring);

pSub_1 = cJSON_GetObjectItem(pRoot, "xStr");

if(NULL == pSub_1)

{

cJSON_Delete(pRoot);

return 4;

}

printf("get xStr : [%s]\n", pSub_1->valuestring);

pSub_1 = cJSON_GetObjectItem(pRoot, "subobject_1");

if(NULL == pSub_1)

{

cJSON_Delete(pRoot);

return 5;

}

printf("get Sub Obj 1\n");

cJSON * pSub_2 = cJSON_GetObjectItem(pSub_1, "bStr");

if(NULL == pSub_2)

{

cJSON_Delete(pRoot);

return 6;

}

printf("get bStr : [%s]\n", pSub_2->valuestring);

pSub_2 = cJSON_GetObjectItem(pSub_1, "subobject_2");

if(NULL == pSub_2)

{

cJSON_Delete(pRoot);

return 7;

}

printf("get Obj 2\n");

cJSON * pStr = cJSON_GetObjectItem(pSub_2, "cStr");

if(NULL == pStr)

{

cJSON_Delete(pRoot);

return 8;

}

printf("get cStr : [%s]\n", pStr->valuestring);

cJSON_Delete(pRoot);

return 0;

}

int main()

{

char * pJson = makeJson();

printf("JSON:\n%s\n", pJson);

parseJson(pJson);

free(pJson);

return 0;

}

编译

$ gcc -o nestcjson nestcjson.c cjson.c -lm

注：编译时链接的库 -lm 是数学库，不加此库时 gcc 返回错误，错误代码如下

$ gcc -o nestcjson nestcjson.c cjson.c

/tmp/ccugp95L.o: In function `parse_number':

cjson.c:(.text+0x402): undefined reference to `pow'

/tmp/ccugp95L.o: In function `print_number':

cjson.c:(.text+0x512): undefined reference to `floor'

collect2: ld 返回 1

运行

$ ./nestcjson

JSON:

{

"aStr": "aaaaaaa",

"subobject_1": {

"bStr": "bbbbbbb",

"subobject_2": {

"cStr": "ccccccc"

}

},

"xStr": "xxxxxxx"

}

get aStr : [aaaaaaa]

get xStr : [xxxxxxx]

get Sub Obj 1

get bStr : [bbbbbbb]

get Obj 2

get cStr : [ccccccc]

作者：风波

mail : fengbohello@qq.com