在postman中 PUT----》body----》raw----》json

 结构体定义：

#define MAX_ARRAY_SIZE      5*1024*1024


struct SMART_DATA_CACHE
{
    char* buf;
    long dwTotalLen;

    SMART_DATA_CACHE()
    {
        dwTotalLen = 0;
        buf = nullptr;
        while (!buf) {
            try {
                buf = new char[MAX_ARRAY_SIZE];
            }
            catch (...) {}
        }
        memset(buf, 0x00, MAX_ARRAY_SIZE);
    }
    ~SMART_DATA_CACHE()
    {
        if (buf) {
            delete[] buf;
            buf = nullptr;
            dwTotalLen = 0;
        }
    }
};

接收服务器返回信息的函数：

size_t ManageCurl::http_recv_cb(void* ptr, size_t size, size_t nmemb, void* stream)
{
	SMART_DATA_CACHE* pDataBuf = (SMART_DATA_CACHE*)stream;
	if (pDataBuf) {
		if (pDataBuf->buf) {
			if (pDataBuf->dwTotalLen + size * nmemb < MAX_ARRAY_SIZE) {
				memcpy(pDataBuf->buf + pDataBuf->dwTotalLen, ptr, size * nmemb);
				pDataBuf->dwTotalLen += size * nmemb;
			}
		}
	}

	return size * nmemb;
}

通过libcurl代码方式：

bool ManageCurl::http_UploadClassID(const char* pUrl, const char* pInfo/*json*/, long nTimeout, SMART_DATA_CACHE& stRecv)
{
	bool bResult = false;

	//
	memset(stRecv.buf, 0, MAX_ARRAY_SIZE);
	stRecv.dwTotalLen = 0;

	//
	CURL* curl = curl_easy_init();
	if (curl) {
		struct curl_slist* http_header = NULL;
		//http_header = curl_slist_append(http_header, "Expect:");
		//http_header = curl_slist_append(http_header, "User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US) AppleWebKit/534.3 (KHTML, like Gecko) Chrome/6.0.472.63 Safari/534.3");
		http_header = curl_slist_append(http_header, "Charset: UTF-8");
		http_header = curl_slist_append(http_header, "Connection: keep-alive");//保持长连接
		http_header = curl_slist_append(http_header, "Content-Type: application/json");//保持长连接

		curl_easy_setopt(curl, CURLOPT_HTTPHEADER, http_header);//修改协议头
		curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, http_recv_cb);//设置接收回调
		curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void*)&stRecv);//设置设置参数
		curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT, 10);//设置连接时的超时时间为5秒
		curl_easy_setopt(curl, CURLOPT_TIMEOUT, nTimeout);//超时秒为单位
		curl_easy_setopt(curl, CURLOPT_URL, pUrl);//指定URL
		curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0);
		curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0);
		curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, "PUT"); /* !!! */
		curl_easy_setopt(curl, CURLOPT_POSTFIELDS, pInfo); /* data goes here */
		CURLcode res = curl_easy_perform(curl);//执行

		long nRet = 0;
		CURLcode codeRet = curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &nRet);
		if (codeRet == CURLE_OK && nRet == 200) {
			bResult = true;
		}

		curl_easy_cleanup(curl);
		curl_slist_free_all(http_header);
	}

	return bResult;
}