記憶登錄跳轉(zhuǎn)可以打打方便用戶使用
getHeader("Referer");方式簡單不過不能處理post的參數(shù)
本來都是用在struts,webwork里的，為了容易看明白改寫成jsp方式的

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member.jsp   //session限制訪問頁

<%
String url = ""
if(session.getAttribute("username")==null)
{
         url = myRedirect.dealurl(request);//記錄當(dāng)前地址和請求參數(shù)，dealurl將實(shí)際url處理了避免和要請求url有干擾,因?yàn)闀?amp; 字符
         response.sendRedirect("weblogin.jsp?url＝"+url) ;//重定向到登錄頁面
}
%>
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weblogin.jsp

<%
String url = request.getParameter("url");
String userid =request.getParameter("userid");
String passWord =request.getParameter("password");
if(userid!=null) //如果是登錄提交執(zhí)行下面代碼
{

 if(登錄成功)
  {
   session.setAttribute("userid",userid);
   out.  }else{
   out.println("<script>alert('用戶名或密碼錯誤');history.back();</script>");
  }
}else{//如果不是登錄提交顯示現(xiàn)面登錄界面
%>
<table width="311" height="162" border="0" align="center" cellpadding="0" cellspacing="0">
  <tr>
     
    <td width="311" height="162" align="center"> 您還沒有登錄，請先登錄<br>
        <table width="155" border="0" cellpadding="0" cellspacing="5" class="font12">
  <form  name="loginfrm" action="weblogin.jsp" method="post"  id="loginfrm" onSubmit="return checkfrm();">
          <tr>
            <td width="41" height="33" valign="bottom">帳&nbsp;號：</td>
            <td width="99" valign="bottom"><input name="userid" type="text" class="textstyle" id="userid" size="12" style="height:20"></td>
          </tr>
          <tr>
            <td>密&nbsp;碼：</td>
            <td><input name="password" type="password" class="textstyle" id="password" size="12" style="height:20;width:94"></td>
          </tr>
          <tr align="center" valign="bottom">
            <td height="21" colspan="2"> <input type="submit" name="Submit" value="登錄">
              &nbsp; <a href="reg.jsp" target="_blank">沒有注冊</a>&nbsp; </td>
          </tr>
          <tr align="center">
            <td colspan="2" class="font14"><strong><a href="#" onclick="MM_openBrWindow('requestpwd.jsp','pwd','width=300,height=200');return false;">找回密碼</a></strong></td>
          </tr>
    <input name="url" type="hidden" value="<%=url%>">這里要有個hidden來保存一下，不然提交就沒了
   
    </form>
        </table>

 
     
    </td>
  </tr>
</table>
<%
}
%>

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myRedirect.java

package com.util;

import javax.servlet.http.HttpServletRequest;
import java.util.Enumeration;

public class myRedirect    //對url的轉(zhuǎn)換類
{
 public static String dealurl(HttpServletRequest request)
 {
  String url = "";
  url = request.getRequestURL()+"?";
  url +=param(request);
  if(url.indexOf("&")>-1)
   url=url.replaceAll("&","@#@");//實(shí)際上就是把有&的字符轉(zhuǎn)化成了@#@
  return url;
 }
 public static String geturl(String url)//這個是還原方法
 {
  if(url.indexOf("@#@")>-1)
   url=url.replaceAll("@#@","&");
  return url;    
 }
 public static String param(HttpServletRequest request)
 {
  String url = "";
  Enumeration param = request.getParameterNames();//得到所有參數(shù)名
  while(param.hasMoreElements())
  {
   String pname = param.nextElement().toString();
   url += pname+"="+request.getParameter(pname)+"&";
  }
  if(url.endsWith("&"))
  {
   url = url.substring(0,url.lastIndexOf("&"));
  }
  return url;
 }
}
這樣登錄瀏覽器就會自動轉(zhuǎn)到用戶剛剛請求的地址