如何用bean和servlet进行登录验证(不要用struts)

Question

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

Answer 1

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");
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 !");
}

}

}
=============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>/loginAction</url-pattern>
</servlet-mapping>

</web-app>