下载网页源码

#include "pch.h"
#include<windows.h>

#include<Wininet.h>

#include<iostream>

#include<fstream>

#include<string>

#pragma comment(lib,"WinInet.lib")

using namespace std;

class web 
{
public:
	web(string url);
	~web();
    int CatchData();

private:
	HINTERNET hINet, hHttpFile;
	char szSizeBuffer[32];
	DWORD dwLengthSizeBuffer = sizeof(szSizeBuffer);
	string url;     
};


web::web(string url)
{
	this->url = url;

	hINet = InternetOpen("IE6.0", INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL, 0);    //InternetOpen初始化WININET.DLL
	if (!hINet)

	{

		cout << "InternetOpen fail" << endl;

	}

	hHttpFile = InternetOpenUrl(hINet, url.c_str(), NULL, 0, 0, 0);  //这个函数连接到一个网络服务器上并且最被从服务器上读取数据

	if (!hHttpFile)

	{

		cout << "error open url" << endl;

	}
}

web::~web() 
{
	InternetCloseHandle(hHttpFile);   //关闭句柄
	InternetCloseHandle(hINet);
}


int web::CatchData() 
{
	BOOL bQuery = HttpQueryInfo(hHttpFile,

		HTTP_QUERY_CONTENT_LENGTH,

		szSizeBuffer,

		&dwLengthSizeBuffer, NULL); //得到关于文件的信息,将接收到的资源大小存到szSizeBuffer当中，以字节为单位。

	if (bQuery == false)

	{

		InternetCloseHandle(hINet);

		cout << "error query info" << endl;

		return 3;

	}

	int FileSize = atol(szSizeBuffer);    //atol函数把字符串转换成长整型数

	string revData;

	revData.resize(FileSize);//根据得到的网页资源的大小信息来重新分配缓冲区字符串的大小


	DWORD dwBytesRead;

	BOOL bRead = InternetReadFile(hHttpFile, &revData[0], FileSize, &dwBytesRead);     //web浏览器将在InternetReadFile上循环 ，不停地从Internet上读入数据块。



	if (!bRead)

	{

		cout << "error to read file" << endl;

		return 4;

	}

	ofstream   out_file("test.txt");
	out_file << revData;              //输出到文件

	cout << "抓取成功!\n" << endl;

	system("pause");

	return 0;

}

int main()
{
	web w("https://www.sina.com.cn/");
	w.CatchData();
}