C語言是一種強大的編程語言，可以用于許多不同的領域，包括獲取網頁上的JSON。獲取JSON有兩種方法：使用現有的庫或通過手動解析。

//方法一：使用現有的庫
#include#include#include#includeint main() {
CURL *curl;
CURLcode res;
char *url = "https://jsonplaceholder.typicode.com/todos/1";
char *json_string;
json_t *root;
json_error_t error;
curl_global_init(CURL_GLOBAL_DEFAULT);
curl = curl_easy_init();
if(curl) {
curl_easy_setopt(curl, CURLOPT_URL, url);
curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L);
res = curl_easy_perform(curl);
if(res != CURLE_OK) {
fprintf(stderr, "curl_easy_perform() failed: %s\n", curl_easy_strerror(res));
curl_easy_cleanup(curl);
curl_global_cleanup();
return 1;
}
json_string = curl_easy_strerror(curl, CURLOPT_WRITEFUNCTION, json_string);
root = json_loads(json_string, 0, &error);
printf("JSON Object:\n%s\n", json_dumps(root, JSON_ENCODE_ANY));
json_decref(root);
curl_easy_cleanup(curl);
}
curl_global_cleanup();
return 0;
}
//方法二：手動解析JSON
#include#include#includetypedef struct {
char *data;
size_t size;
} MemoryStruct;
void *httpget(const char *url) {
CURL *curl;
CURLcode res;
MemoryStruct *chunk = malloc(sizeof(MemoryStruct));
chunk->size = 0;
chunk->data = malloc(1);
curl_global_init(CURL_GLOBAL_DEFAULT);
curl = curl_easy_init();
if(curl) {
curl_easy_setopt(curl, CURLOPT_URL, url);
curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L);
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_memory_callback);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, chunk);
res = curl_easy_perform(curl);
if(res != CURLE_OK) {
fprintf(stderr, "curl_easy_perform() failed: %s\n", curl_easy_strerror(res));
free(chunk->data);
free(chunk);
curl_easy_cleanup(curl);
curl_global_cleanup();
return NULL;
}
curl_easy_cleanup(curl);
}
curl_global_cleanup();
return chunk;
}
int main() {
char *url = "https://jsonplaceholder.typicode.com/todos/1";
char *httpget_output;
MemoryStruct *chunk;
int len;
char *buffer;
httpget_output = httpget(url);
if(!httpget_output) {
printf("Failed to perform HTTP GET request!\n");
return 1;
}
chunk = (MemoryStruct *)httpget_output;
len = chunk->size;
buffer = (char *)malloc(len);
if(!buffer) {
printf("Failed to allocate memory!\n");
free(chunk->data);
free(chunk);
return 1;
}
memcpy(buffer, chunk->data, len);
// 解析 JSON 數據并提取所需信息
free(chunk->data);
free(chunk);
free(buffer);
return 0;
}

無論您選擇哪種方法，都需要使用CURL庫來獲取JSON數據。安裝CURL庫后，您可以輕松獲取網頁上的JSON數據。如果JSON數據較大，則手動解析可能需要更多時間和努力，但是使用現有的庫則可以使整個過程變得更加便捷。