java 實現web 登陸

web 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();

}