1、json的数据结构

c语言中json数据是采用链表存储的

typedef struct cJSON {

struct cJSON *next,*prev;// 数组 对象数据中用到

struct cJSON *child;// 数组 和对象中指向子数组对象或值

int type;// 元素的类型，如是对象还是数组

char *valuestring;// 如果是字符串

int valueint;// 如果是数值

double valuedouble;// 如果类型是cJSON_Number

char *string;// The item's name string,if this item is the child of,or is in the list of subitems of an object.

} cJSON;

{

"name": "Jack (\"Bee\") Nimble",

"format": {

"type": "rect",

"width": 1920,

"height": 1080,

"interlace": false,

"frame rate": 24

}

}

"name": "Jack (\"Bee\") Nimble",

"format": {

"type": "rect",

"width": 1920,

"height": 1080,

"interlace": false,

"frame rate": 24

}

}

1、字符串解析成json结构体

1)：讲字符串解析成json结构体。

cJSON *root = cJSON_Parse(my_json_string);

2):获取某个元素

cJSON *format = cJSON_GetObjectItem(root,"format");

int framerate = cJSON_GetObjectItem(format,"frame rate")->valueint;

int framerate = cJSON_GetObjectItem(format,"frame rate")->valueint;

3）:讲json结构体转换成字符串

char *rendered=cJSON_Print(root);

4）：删除

cJSON_Delete(root);

2：构建一个json结构体

cJSON *root,*fmt;

root=cJSON_CreateObject();

cJSON_AddItemToObject(root,"name",cJSON_CreateString("Jack (\"Bee\") Nimble"));

cJSON_AddItemToObject(root,"format",fmt=cJSON_CreateObject());

cJSON_AddStringToObject(fmt,"type","rect");

cJSON_AddNumberToObject(fmt,"width",1920);

cJSON_AddNumberToObject(fmt,"height",1080);

cJSON_AddFalseToObject (fmt,"interlace");

cJSON_AddNumberToObject(fmt,"frame rate",24)

out =cJSON_Print(root);

printf("%s\n",out);

cJSON_Delete(root);

free(out);