java HttpURLConnection 登录网站 完整代码

import java.io.*;
import java.util.*;
import java.net.*;

public class WebTest {

	public static void main(String[] args) {

		System.out.println("beging...");
		DownLoadPages("http://login.xiaonei.com/Login.do", "d:/fileDown.txt");
		// visit("http://www.xiaonei.com");
		System.out.println("end.");
	}

	public static void DownLoadPages(String urlStr, String outPath) {
		int chByte = 0;

		URL url = null;

		HttpURLConnection httpConn = null;

		InputStream in = null;

		FileOutputStream out = null;

		try {
			String post = "email=" + URLEncoder.encode("e-mail", "UTF-8")
					+ "&password=" + "password";
			url = new URL(urlStr);

			httpConn = (HttpURLConnection) url.openConnection();

			//setInstanceFollowRedirects can then be used to set if 
			//redirects should be followed or not and this should be used before the
			//connection is established (via getInputStream, getResponseCode, and other
			//methods that result in the connection being established).

			httpConn.setFollowRedirects(false);

			//inorder to disable the redirects
			httpConn.setInstanceFollowRedirects(false);

			httpConn.setDoOutput(true);
			httpConn.setDoInput(true);
			httpConn.setRequestProperty("User-Agent",
					"Mozilla/5.0 (compatible; MSIE 6.0; Windows NT)");
			httpConn.setRequestProperty("Content-Type",
					"application/x-www-form-urlencoded");

			//ok now, we can post it
			PrintStream send = new PrintStream(httpConn.getOutputStream());
			send.print(post);
			send.close();
			URL newURL = new URL(httpConn.getHeaderField("Location"));
			System.out.println("the URL has move to "
					+ httpConn.getHeaderField("Location"));
			httpConn.disconnect();

			//			 OK, now we are ready to get the cookies out of the URLConnection	
			String cookies = getCookies(httpConn);
			System.out.println(cookies);
			httpConn = (HttpURLConnection) newURL.openConnection();
			httpConn.setRequestProperty("User-Agent",
					"Mozilla/5.0 (compatible; MSIE 6.0; Windows NT)");
			httpConn.setRequestProperty("Content-Type",
					"application/x-www-form-urlencoded");
			httpConn.setRequestProperty("Cookie", cookies);

			httpConn.setDoInput(true);
			in = httpConn.getInputStream();
			out = new FileOutputStream(new File(outPath));

			chByte = in.read();
			while (chByte != -1) {
				out.write(chByte);
				//System.out.println(chByte);
				chByte = in.read();
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	public static String getCookies(HttpURLConnection conn) {
		StringBuffer cookies = new StringBuffer();
		String headName;
		for (int i = 7; (headName = conn.getHeaderField(i)) != null; i++) {
			StringTokenizer st = new StringTokenizer(headName, "; ");
			while (st.hasMoreTokens()) {
				cookies.append(st.nextToken() + "; ");
			}
		}
		return cookies.toString();
	}
}