文档： https://github.com/DaveGamble/cJSON

项目结构

.
├── libs
│   ├── cJSON.c
│   └── cJSON.h
└── main.c

示例

struct 转 json

#include "libs/cJSON.h"
#include <stdio.h>// define data struct
typedef struct Student
{int age;char *name;
} Student;int main(int argc, char const *argv[])
{// 1. create structStudent student;student.age = 18;student.name = "Tom";// 2. struct to json objectcJSON *item = cJSON_CreateObject();if (cJSON_AddStringToObject(item, "name", student.name) == NULL){goto end;}if (cJSON_AddNumberToObject(item, "age", student.age) == NULL){goto end;}// 3. print json stringchar *json = cJSON_Print(item);printf("%s\n", json);// 4. free json
end:cJSON_Delete(item);return 0;
}

输出

$ gcc main.c libs/cJSON.c && ./a.out{"name": "Tom","age":  18
}

json 转 struct

#include "libs/cJSON.h"
#include <stdio.h>
#include <memory.h>// define data struct
typedef struct Student
{int age;char *name;
} Student;char *Student_to_string(char *result, Student *student)
{if (student == NULL){return result;}sprintf(result,"Student {\n name: \"%s\",\n age: %d\n}\n",student->name,student->age);return result;
}int main(int argc, char const *argv[])
{Student student;cJSON *item;cJSON *name_item;cJSON *age_item;char result[100];char *json = "{\"name\": \"Tom\",\"age\":  18}";// 1. parse jsonitem = cJSON_Parse(json);if (item == NULL){const char *error_ptr = cJSON_GetErrorPtr();if (error_ptr != NULL){fprintf(stderr, "Error before: %s\n", error_ptr);}goto end;}// 2. convert to structname_item = cJSON_GetObjectItem(item, "name");if(cJSON_IsString(name_item) && name_item->valuestring != NULL){student.name = name_item->valuestring;}age_item = cJSON_GetObjectItem(item, "age");if(cJSON_IsNumber(age_item)){student.age = age_item->valueint;}Student_to_string(result, &student);printf("%s", result);end:// 3. free jsoncJSON_Delete(item);return 0;
}

输出

$ gcc main.c libs/cJSON.c && ./a.outStudent {name: "Tom",age: 18

参考

cJSON库学习——C语言结构体与JSON互相转换
https://www.cnblogs.com/BearMan0047/p/16063422.html