Servlet 登录 继续！！！

XML配置

<?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>
    <description>This is the description of my J2EE component</description>
    <display-name>This is the display name of my J2EE component</display-name>
    <servlet-name>LoginServlet</servlet-name>
    <servlet-class>servlet.LoginServlet</servlet-class>
  </servlet>

  <servlet-mapping>
    <servlet-name>LoginServlet</servlet-name>
    <url-pattern>/LoginServlet</url-pattern>
  </servlet-mapping>
</web-app>
 

servlet 文件

 

package servlet;

import java.io.IOException;
import java.io.PrintWriter;

import javax.naming.NamingException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.sql.*;

public class LoginServlet extends HttpServlet ...{

    /** *//**
     * 
     */
    private static final long serialVersionUID = 1L;
    /** *//**
     * The doGet method of the servlet. <br>
     *
     * This method is called when a form has its tag value method equals to get.
     * 
     * @param request the request send by the client to the server
     * @param response the response send by the server to the client
     * @throws ServletException if an error occurred
     * @throws IOException if an error occurred
     */
    private static final String CONTENT_TYPE = "text/html; charset=GBK";
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException ...{
        //request.setCharacterEncoding("gbk");
        //response.setCharacterEncoding("gbk");
        response.setContentType(CONTENT_TYPE);
        PrintWriter out = response.getWriter();

        out.println("<script>alert('请从页面提交');history.back()</script>");
        
        out.flush();
        out.close();
    }

    /** *//**
     * The doPost method of the servlet. <br>
     *
     * This method is called when a form has its tag value method equals to post.
     * 
     * @param request the request send by the client to the server
     * @param response the response send by the server to the client
     * @throws ServletException if an error occurred
     * @throws IOException if an error occurred
     */
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException ...{

        response.setContentType(CONTENT_TYPE);
        PrintWriter out = response.getWriter();
        //------------------------------------------------------------------------
        String username= request.getParameter("username");
        String password = request.getParameter("password");
        PreparedStatement prep = null;
        ResultSet rs = null;
            try ...{
                Connection conn = common.conn.ConnectionPool.getConnection();
                prep = conn.prepareStatement("select * from users where username=? and password=?");
                prep.setString(1, username);
                prep.setString(2, password);
                rs = prep.executeQuery();
                if(rs.next())...{
                    out.println("登陆成功");
                }else...{
                    out.println("用户名/密码错误");
                }
            } catch (NamingException e) ...{
                
                e.printStackTrace();
            } catch (SQLException e) ...{
            
                e.printStackTrace();
            }finally...{
                try...{
                if(prep!=null)prep.close();
                common.conn.ConnectionPool.closeConnection();
                }catch(SQLException e)...{
                    out.print("数据库出错,请联系管理员");
                }
            }
        //------------------------------------------------------------------------
        out.flush();
        out.close();
    }

}

哦了  这样好看  下次注意这样放上！ 哈哈