java實現web登陸

 web登陸無非就是網頁擷取，cookie 的管理，post和get方式的類比。

1.網頁內容擷取
     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();
     //類比成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(";"));

}  發送設定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/ )
擷取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);

新的請求,利用上面擷取的cookie:

url = new URL("http://www.site.com/");

huc = (HttpURLConnection) url.openConnection();

client.setCookies(huc, cj);

3.post方式的類比
URL url = new URL("www.xyz.com");
  HttpURLConnection huc = (HttpURLConnection) url.openConnection();
//設定允許output
  huc.setDoOutput(true);
//設定為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資訊
 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();

}

結束語：
     上面的代碼基本就可以實現網站的登陸、資訊擷取的功能。看到登陸奇兵等軟體賣的那麼火，我們也做一個去吧.

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