查看他的登陆页面的代码， 看他提交到哪个页面， 变量是什么。

<form method="post" action="login.jsp"> 
<table align="center" width="40%" style="FONT-SIZE: 12px" border="0" cellpadding="0" cellspacing="2"> 
  <tr> 
    <td width="30%" align="right" bgcolor="#0073AA" style="FONT-SIZE: 12px;color:#ffffff">name:</td> 
    <td width="70%"><input type="text" size="30" name="username"></td> 
  </tr> 
  <tr> 
    <td width="30%" align="right" bgcolor="#0073AA" style="FONT-SIZE: 12px;color:#ffffff">password:</td> 
    <td width="70%"><input type="password" size="32" name="passwd"></td> 
  </tr> 
  <tr> 
    <td colspan="2" align="right"> 
      <input type="submit" name="submit" value="Login">  
      <input type="button" name="submit" value="regest" onclick="location.href='regest.jsp'"> 
    </td> 
  </tr> 
</table> 
</form> 

很明显， 如果你要登陆， 你需要把username, passwd, submit这几个变量post到login.jsp， 而且submit=Login
用以下代码：

<?php 
        $postData = "username=your_name&password=your_password&Submit=Login"; 
        $posturl = "http://......../../login.jsp"; 

        $postUrl = parse_url($posturl); 
        $host = $postUrl[host] ? $postUrl[host] : ""; 
        $port = $postUrl[port] ? $postUrl[port] : 80; 
        $path = $postUrl[path] ? $postUrl[path] : "/"; 



        $fsp = fsockopen($host, $port, &$errno, &$errstr, 30); 
        if(!$fsp){ 
                print "\nopen socket failed\n"; 
        }else{ 
                fwrite($fsp, "POST ".$path." HTTP/1.1\r\n"); 
                fwrite($fsp, "Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-shockwave-flash, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*\r\n"); 
                fwrite($fsp, "Accept-Language: zh-cn\r\n"); 
                fwrite($fsp, "Content-Type: application/x-www-form-urlencoded\r\n"); 
                fwrite($fsp, "User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; Maxthon)\r\n"); 
                fwrite($fsp, "Host:".$host."\r\n"); 
                fwrite($fsp, "Content-Length: ".strlen($postData)."\r\n\r\n"); 
                fwrite($fsp, $postData); 

                $resp = ""; 
                do{ 
                        if(strlen($out=fread($fsp, 1024)) == 0) break; 
                        $resp .= $out; 
                }while(true); 

                echo "<br><br>".nl2br($resp); 

                fclose($fsp); 

        } 
?>