如何使用 cJSON 在名称/值对中查找名称

Question

cJSON provides a function

CJSON_PUBLIC(cJSON *) cJSON_GetObjectItemCaseSensitive(const cJSON * const object, const char * const string)

I created a test function

#include "cJSON.h"
const char *jsonstring = "{\"b\": {\"b1\":\"2b\"}}";

void jsontest(void)
{
  cJSON *cJSON_data = cJSON_Parse(jsonstring);
  char *buffer = cJSON_Print(cJSON_data);
  printf("JSON_String:%s\r\n",buffer);
  cJSON *bfound = cJSON_GetObjectItemCaseSensitive(cJSON_data,"b1");
  printf("bfound: 0x%08x\n",(char*)bfound);
  free(cJSON_data);
  free(buffer);
}

The output is

JSON_String:{
    "b":    {
        "b1":   "2b"
    }
}

bfound: 0x00000000

`

If I use this string,

const char *jsonteststr1 = "{\\"a\\":\\"1\\",\\"b\\":\\"2\\",\\"c\\":\\"3\\"}";

GetObjectItemCaseSensitive() will find "a", "b", and "c".

GetObjectItemCaseSensitive() does not seem to recurse.

Am I doing something wrong? Do I not understand how to use GetObjectItem() ?

I am using version 1.7.12

Answer 1

cJSON_GetObjectItemCaseSensitive(object, string) can only get the the direct child and child's siblings of object , we can't find the child's child node through it.

if you want to get the value of 2b , then you should:

#include "cJSON.h"
const char *jsonstring = "{\"b\": {\"b1\":\"2b\"}}";

void jsontest(void)
{
  cJSON *cJSON_data = cJSON_Parse(jsonstring);
  char *buffer = cJSON_Print(cJSON_data);
  printf("JSON_String:%s\r\n",buffer);
  cJSON *bfound = cJSON_GetObjectItemCaseSensitive(cJSON_data,"b");  // cJSON_data only has a child which named "b"
  cJSON *b1_found = cJSON_GetObjectItemCaseSensitive(bfound, "b1");  // key/value: <b1, 2b> is in b1_found, not bfound
  printf("b1_found: 0x%08x\n",(char*)b1_found);
  printf("bfound: 0x%08x\n",(char*)bfound);

  cJSON_Delete(cJSON_data);  // you should use cJSON_Delete to free the json item.
  free(buffer);
}