java web 登陆解决方法

项目中遇到从系统A登陆到系统B的问题，登陆验证用的是Spring Security
当配置了Spring Security 后可以可以直接在跳转的时候 传递用户名 密码即可实现登陆

http://${projectHost}/j_spring_security_check?j_username=${userName}&j_password=${password}"

Spring Security的配置方法找度娘

复制：
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){

System.out.printli(line);

line = br.readLine();

}