如何用bean和servlet进行登录验证(不要用struts)
当用bean和servlet进行登录验证时,如何配置?那个web.xml如何设置?
各个文件如下;我想从登录界面login.jsp提交数据到loginBean.java里处理,处理成功就转到welcome.jsp页面
下面应该有错,但错在哪里?应该如何做?有没有相关的例子

==========login.jsp================
主要代码:
<form   action= "loginAction "   method= "post ">
        username: <input   type= "text "   name= "username "   /> <br>
        password:   <input   type= "text "   name= "password "   />
        <br>
        <input   type= "submit "   value= "login "/>


</form>

==========loginBean.java==========
package   cn.fzu;
import   javax.servlet.http.HttpServlet;
import   javax.servlet.*;
import   javax.servlet.http.*;
import   java.io.*;

public   class   loginBean   extends   HttpServlet{

public   void   doGet(HttpServletRequest   request,HttpServletResponse   response)   throws   ServletException,IOException
{
HttpSession   session=request.getSession();
String   user=request.getParameter( "username ");
String   pawd=request.getParameter( "password ");
System.out.println(user);
if(user.equals( "sa ")&&pawd.equals( "123 "))
{

response.sendRedirect( "welcome.jsp ");

}
else
{
System.out.println( "hava   wrong   ! ");
}

}

}
==============welcome.jsp=======
略去
=============web.xml===========
<?xml   version= "1.0 "   encoding= "UTF-8 "?>
<web-app   version= "2.4 "  
xmlns= "http://java.sun.com/xml/ns/j2ee "  
xmlns:xsi= "http://www.w3.org/2001/XMLSchema-instance "  
xsi:schemaLocation= "http://java.sun.com/xml/ns/j2ee  
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd ">

<servlet>
    <servlet-name> loginAction </servlet-name>
    <servlet-class> cn.fzu.loginBean </servlet-class>
</servlet>

<servlet-mapping>
    <servlet-name> loginAction </servlet-name>
    <url-pattern> /* </url-pattern>
</servlet-mapping>

</web-app>

谢谢先

------解决方案--------------------
修改如下，其余代码不变。

==========loginBean.java==========
package cn.fzu;
import javax.servlet.http.HttpServlet;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;

public class loginBean extends HttpServlet{

public void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException
{
this.doGet(request,response);
}

public void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException
{
HttpSession session=request.getSession();
String user=request.getParameter( "username ");