读取json文件

网上找了一圈都没有看到直接处理json文件的代码，只看到处理json数据的。所以就自己总结了一个json文件的读取处理代码。直接上代码

#include 
#include "cJSON.h"


int main()
{
    const char* version = cJSON_Version();
    printf("version:%s\n", version);
    FILE* file = fopen("./test.json", "r");
    if(NULL == file)
    {
        printf("load file fail!\n");
        return -1;
    }
    
    fseek(file, 0, SEEK_END);
    long size = ftell(file);
    fseek(file, 0, SEEK_SET);
    char* tmpStr = (char*)malloc(size + 1);
    memset(tmpStr, 0, size + 1);
    size_t ret = fread(tmpStr, size, 1, file);
    tmpStr[size] = '\0';
    printf("ret = %d size = %ld str=%s\n", ret, size, tmpStr);

    cJSON* root = cJSON_Parse(tmpStr); 
    cJSON* map_id = cJSON_GetObjectItem(root,"map_id");
    if(NULL != map_id)
        printf("mapid is %d\n",map_id->valueint);

    cJSON *rect = cJSON_GetObjectItem(root, "rect");
    if(NULL != rect)
    {
        if(cJSON_IsArray(rect))
        {
            int len = cJSON_GetArraySize(rect);
            for(int i = 0; i < len; i++)
            {    
                cJSON* pos = cJSON_GetArrayItem(rect, i);                    
                printf("i=%d value = %d\n", i, pos->valueint);
            }
        }
        else
        {
            printf("the rect is not an array!\n");
        }       
    }
    else
    {
        printf("rect is null\n");
    }

    cJSON *areas = cJSON_GetObjectItem(root,"areas");
    if(NULL != areas)
    {
        if(cJSON_IsArray(areas))
        {
           int num = cJSON_GetArraySize(areas);
           cJSON* area = areas->child;
           for(int i = 0;ivalueint);
               cJSON* name = cJSON_GetObjectItem(area,"name");
               printf("name = %s\n",name->valuestring);
               cJSON* rect = cJSON_GetObjectItem(area,"rect");
               {
                   if(cJSON_IsArray(rect))
                   {
                       int n = cJSON_GetArraySize(rect);
                       for(int j = 0;jvalueint);
                           }
                       }
                   }
                   else
                   {
                       printf("not a array\n");
                    
                   }
                   
               }               
                area = area->next;
           }
        }
        else
        {
            {
                printf("the areas is not a array\n");
            }
        }
        
    }
    else
    {
        printf("areas is null\n");
    }
    
    
    fclose(file);
    free(tmpStr);

    return 0;
}

json格式如下：包括了数组及嵌套数组等json数据的操作

{

 "map_id":1,

 "map_name":"map1",

 "device_id":"device1",

 "timestamp":123456,

 "rect":[100,200,400,600],

 "area_cnt":"area_cnt",

 "areas":[

        {

            "id":0,

            "name":"area1",

            "rect":[100,100,100,100]

        },

        {

            "id":1,

            "name":"area2",

            "rect":[200,200,200,200]

        },

        {

            "id":3,

            "name":"area3",

            "rect":[300,300,300,300]

        }

    ]

}

 

使用方法：去github上下载一个cjson.h和cjson.cpp,再将自己的read.cpp放到和他们同一级的目录下一起编译，linux和Windows下都能编译。

读取结果如下：

如果找不到json文件就去我的github上找：https://github.com/hddid/Utils，在我的utils下面。