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