java 实现web 登陆

web登陆无非就是网页获取，cookie 的管理，post和get方式的模拟。

1.网页内容获取
     java.io.InputStream  in;
      java.net.URL url = new java.net.URL(www.xyz.com/content.html);
      java.net.HttpURLConnection connection = (java.net.HttpURLConnection)
          url.openConnection();
      connection = (java.net.HttpURLConnection) url.openConnection();
     //模拟成IE
      connection.setRequestProperty("User-Agent","Mozilla/4.0 (compatible; MSIE 6.0; Windows 2000)");
      connection.connect();
      in = connection.getInputStream();
      java.io.BufferedReader breader =
          new BufferedReader(new InputStreamReader(in , "GBK"));
      String str=breader.readLine());
      while(st != null){
        System.out.println(str);
        str=breader.readLine());
      }
2.cookie管理

  1.直接的方式
取得cookie：
HttpURLConnection huc= (HttpURLConnection) url.openConnection(); InputStream is = huc.getInputStream(); // 取得sessionID. String cookieVal = hc.getHeaderField("Set-Cookie"); String sessionId; if(cookieVal != null) {     sessionId = cookieVal.substring(0, cookieVal.indexOf(";")); }

 发送设置cookie： HttpURLConnection huc= (HttpURLConnection) url.openConnection(); if(sessionId != null) { huc.setRequestProperty("Cookie", sessionId); } InputStream is = huc.getInputStream();

2.利用的jcookie包(http://jcookie.sourceforge.net/ )
获取cookie:
URL url = new URL("http://www.site.com/"); HttpURLConnection huc = (HttpURLConnection) url.openConnection(); huc.connect(); InputStream is = huc.getInputStream(); Client client = new Client(); CookieJar cj = client.getCookies(huc);

新的请求,利用上面获取的cookie:

url = new URL("http://www.site.com/"); huc = (HttpURLConnection) url.openConnection(); client.setCookies(huc, cj);

3.post方式的模拟
URL url = new URL("www.xyz.com");
  HttpURLConnection huc = (HttpURLConnection) url.openConnection();
//设置允许output
  huc.setDoOutput(true);
//设置为post方式
  huc.setRequestMethod("POST");
  huc.setRequestProperty("User-Agent","Mozilla/4.7 [en] (Win98; I)");
  StringBuffer sb = new StringBuffer();
  sb.append("userName="+userNme);
  sb.append("&password="+password);

//post信息
 OutputStream os = huc.getOutputStream();
 os.write(sb.toString().getBytes("GBK"));
 os.close();

BufferedReader br = new BufferedReader(new InputStreamReader(huc.getInputStream()))

huc.connect();

String line = br.readLine();

while(line != null){

l

System.out.printli(line);

line = br.readLine();

}

结束语：
     上面的代码基本就可以实现网站的登陆、信息获取的功能。看到登陆奇兵等软件卖的那么火，我们也做一个去吧.

参考:
1.A recipe for cookie management
http://www.javaworld.com/javaworld/jw-04-2002/jw-0426-cookie.html

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