C語言是一種強大的編程語言，其應用場景廣泛，使用范圍極廣。本文將介紹如何使用C語言獲取POST請求中的JSON數據。

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
struct Memory {
char *memory;
size_t size;
};
static size_t write_callback(char *ptr, size_t size, size_t nmemb, void *userdata) {
struct Memory *mem = (struct Memory *)userdata;
size_t realsize = size * nmemb;
mem->memory = realloc(mem->memory, mem->size + realsize + 1);
if (mem->memory) {
memcpy(&(mem->memory[mem->size]), ptr, realsize);
mem->size += realsize;
mem->memory[mem->size] = 0;
}
return realsize;
}
char *get_post_json(char *url, char *post_data) {
CURL *curl;
CURLcode res;
char *response = NULL;
struct Memory chunk = {0};
curl_global_init(CURL_GLOBAL_DEFAULT);
curl = curl_easy_init();
if (curl) {
struct curl_slist *headers = NULL;
headers = curl_slist_append(headers, "Content-Type: application/json");
curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);
curl_easy_setopt(curl, CURLOPT_URL, url);
curl_easy_setopt(curl, CURLOPT_POSTFIELDS, post_data);
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_callback);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&chunk);
res = curl_easy_perform(curl);
curl_easy_cleanup(curl);
response = chunk.memory;
curl_slist_free_all(headers);
}
curl_global_cleanup();
return response;
}

該代碼使用了libcurl庫來執(zhí)行HTTP請求。GET和POST都可以使用該庫來處理，而且非常簡單。通過調用curl_easy_setopt函數設置請求的類型、目標URL、請求正文以及回調函數以獲取響應。在本例中，收到的JSON響應將存儲在一個內存塊中，之后我們可以使用該響應進行后續(xù)操作。