使用C++语言，利用libcurl库，下载指定的https中的文件：比如https://www.xxxx.com/xxx/yyy/zzz.pdf

#include <iostream>
#include <fstream>
#include <curl/curl.h>// 写入数据的回调函数
size_t WriteData(void* ptr, size_t size, size_t nmemb, std::ofstream* stream)
{stream->write(static_cast<char*>(ptr), size * nmemb);return size * nmemb;
}// 分段下载函数
bool DownloadSegment(const std::string& url, std::ofstream& output, long start, long end)
{CURL* curl;CURLcode res;curl = curl_easy_init();if (curl) {// 设置URLcurl_easy_setopt(curl, CURLOPT_URL, url.c_str());// 设置Range头std::string range = std::to_string(start) + "-" + std::to_string(end);curl_easy_setopt(curl, CURLOPT_RANGE, range.c_str());// 设置写入数据的回调函数curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteData);curl_easy_setopt(curl, CURLOPT_WRITEDATA, &output);// 设置SSL选项curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 1L); // 验证服务器的SSL证书curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 2L); // 验证证书上的主机名// 执行请求res = curl_easy_perform(curl);// 清理curl_easy_cleanup(curl);if (res != CURLE_OK) {std::cerr << "curl_easy_perform() failed: " << curl_easy_strerror(res) << std::endl;return false;}return true;}return false;
}// 获取文件大小
long GetFileSize(const std::string& url)
{CURL* curl;CURLcode res;double file_size = 0.0;curl = curl_easy_init();if (curl) {curl_easy_setopt(curl, CURLOPT_URL, url.c_str());curl_easy_setopt(curl, CURLOPT_NOBODY, 1L); // 不下载内容curl_easy_setopt(curl, CURLOPT_HEADER, 1L); // 只获取头部信息// 设置SSL选项curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 1L); // 验证服务器的SSL证书curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 2L); // 验证证书上的主机名res = curl_easy_perform(curl);if (res == CURLE_OK) {res = curl_easy_getinfo(curl, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &file_size);if ((res == CURLE_OK) && (file_size > 0.0)) {curl_easy_cleanup(curl);return static_cast<long>(file_size);}} else {std::cerr << "curl_easy_perform() failed: " << curl_easy_strerror(res) << std::endl;}curl_easy_cleanup(curl);}return -1;
}int main() {std::string url = "https://img.linux.net.cn/lfs/LFS-BOOK-7.7-systemd.pdf"; // 替换为实际URLstd::string output_filename = "/home/licks/https_download/LFS-BOOK-7.7-systemd.pdf";long segment_size = 1024 * 1024; // 1MB// 获取文件大小long file_size = GetFileSize(url);if (file_size == -1) {std::cerr << "Failed to get file size." << std::endl;return 1;}std::cout << "File size: " << file_size << " bytes" << std::endl;// 打开输出文件std::ofstream output(output_filename, std::ios::binary);if (!output.is_open()) {std::cerr << "Failed to open output file." << std::endl;return 1;}// 分段下载for (long start = 0; start < file_size; start += segment_size) {long end = start + segment_size - 1;if (end >= file_size) {end = file_size - 1;}std::cout << "Downloading segment: " << start << "-" << end << std::endl;if (!DownloadSegment(url, output, start, end)) {std::cerr << "Failed to download segment." << std::endl;output.close();return 1;}}// 关闭输出文件output.close();std::cout << "Download complete." << std::endl;return 0;
}

使用的是CMake作为代码工程管理手段：

cmake_minimum_required(VERSION 3.0)
project(download_https)set(CMAKE_CXX_STANDARD 11)add_executable(download_https main.cpp)
target_link_libraries(download_https curl)