使用C語言從后臺獲取JSON數據非常常見，在本文中，我們將詳細介紹如何實現這個過程。

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <winsock2.h>
#pragma comment(lib, "ws2_32.lib")
int main(){
WSADATA wsaData;
WSAStartup(MAKEWORD(2, 2), &wsaData);
SOCKET clientSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
SOCKADDR_IN serverAddr;
serverAddr.sin_family = AF_INET;
serverAddr.sin_port = htons(80);
serverAddr.sin_addr.S_un.S_addr = inet_addr("127.0.0.1");
connect(clientSocket, (SOCKADDR*)&serverAddr, sizeof(serverAddr));
char request[1024];
sprintf(request, "GET /api/json HTTP/1.1\r\nHost: 127.0.0.1\r\nConnection: keep-alive\r\nAccept: */*\r\n\r\n");
send(clientSocket, request, strlen(request), 0);
char response[2048];
memset(response, 0, sizeof(response));
recv(clientSocket, response, sizeof(response), 0);
char* body = strstr(response, "\r\n\r\n") + 4;
printf("%s\n", body);
closesocket(clientSocket);
WSACleanup();
return 0;
}

以上代碼實現了從localhost的端口80獲取JSON數據，我們用套接字創(chuàng)建了一個Socket，然后建立與服務器的連接。構造HTTP請求報文后發(fā)送給服務器，再接收服務器的響應，最后從響應中提取JSON數據。