一个完整的简单jsp+servlet实例，实现简单的登录

春和秋荣 2020-02-22

展开全文

1、先创建web project，项目名为RegisterSystem，

2、在WebRoot 目录下创建login.jsp文件：

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    <title>My JSP 'login.jsp' starting page</title>
	<meta http-equiv="pragma" content="no-cache">
	<meta http-equiv="cache-control" content="no-cache">
	<meta http-equiv="expires" content="0">    
	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
	<meta http-equiv="description" content="This is my page">
	<!--
	<link rel="stylesheet" type="text/css" href="styles.css">
	-->
  </head>
  <body>
    This is my JSP page. <br>
     <form action="login">
    username:<input type="text" name="username"><br>
    password:<input type="password" name="pwd"><br>
    <input type="submit">
    </form>
  </body>
</html>

3、在scr目录下的com.ht.servlet编写AccountBean.java文件，代码如下：

package com.ht.servlet;

public class AccountBean {
private String username;
private String password;
public String getPassword() {
  return password;
}
public void setPassword(String password) {
  this.password = password;
}
public String getUsername() {
  return username;
}
public void setUsername(String username) {
  this.username = username;
}
}

4、在scr目录下的com.ht.servlet编写servlet类CheckAccount.java文件，代码如下：

package com.ht.servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class CheckAccount extends HttpServlet {

@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
doGet(req,resp);
}

@Override
public void doGet(HttpServletRequest req, HttpServletResponse resp)
   throws ServletException, IOException {
  HttpSession session = req.getSession();
  AccountBean account = new AccountBean();
  String username = req.getParameter("username");
  String pwd = req.getParameter("pwd");
  account.setPassword(pwd);
  account.setUsername(username);
  if((username != null)&&(username.trim().equals("jsp"))) {
   if((pwd != null)&&(pwd.trim().equals("1"))) {
    System.out.println("success");
    session.setAttribute("account", account);
    String login_suc = "success.jsp";
    resp.sendRedirect(login_suc);
    return;
   }
  }
  String login_fail = "fail.jsp";
  resp.sendRedirect(login_fail);
  return;
}

}
5、在WebRoot目录下编写success.jsp文件成功后跳转

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@page import="com.ht.servlet.AccountBean"%>    
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    <title>My JSP 'success.jsp' starting page</title>
	<meta http-equiv="pragma" content="no-cache">
	<meta http-equiv="cache-control" content="no-cache">
	<meta http-equiv="expires" content="0">    
	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
	<meta http-equiv="description" content="This is my page">
	<!--
	<link rel="stylesheet" type="text/css" href="styles.css">
	-->
  </head>
  <body>
    <%
    AccountBean account = (AccountBean)session.getAttribute("account");
    %>
    username:<%= account.getUsername()%>
     <br>
     password:<%= account.getPassword() %>
     basePath: <%=basePath%>
    path:<%=path%>
  </body>
</html>

6、在WebRoot目录下编写fail.jsp文件失败后跳转

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    <title>My JSP 'fail.jsp' starting page</title>
	<meta http-equiv="pragma" content="no-cache">
	<meta http-equiv="cache-control" content="no-cache">
	<meta http-equiv="expires" content="0">    
	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
	<meta http-equiv="description" content="This is my page">
	<!--
	<link rel="stylesheet" type="text/css" href="styles.css">
	-->
  </head>
  <body>
     Login Failed! <br>
    basePath: <%=basePath%>
    path:<%=path%>
  </body>
</html>

7、修改web.xml配置文件

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" 
	xmlns="http://java./xml/ns/javaee" 
	xmlns:xsi="http://www./2001/XMLSchema-instance" 
	xsi:schemaLocation="http://java./xml/ns/javaee 
	http://java./xml/ns/javaee/web-app_2_5.xsd">
  <welcome-file-list>
    <welcome-file>login.jsp</welcome-file>
  </welcome-file-list>
  <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>CheckAccount</servlet-name>
       <servlet-class>com.ht.servlet.CheckAccount</servlet-class>
     </servlet>
     <servlet-mapping>
       <servlet-name>CheckAccount</servlet-name>
       <url-pattern>/login</url-pattern>
     </servlet-mapping>
</web-app>

输入测试路径：http://localhost:8080/RegisterSystem/login.jsp

注意：

.处理中文乱码问题

在Sertlet中加

response.setContentType("text/html;charset=utf-8")

在jsp页面中加

<%@ page language="java" import="java.util.*,java.net.URLEncoder" pageEncoding="UTF-8"%>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

在servlet中

String username=request.getParameter("username");

username=new String(username.getBytes(“ISO-8859-1”),"UTF-8");

reference ：http://blog.sina.com.cn/s/blog_5c5bc9070100z7wb.html

http://lelglin./blog/967503

http://zhidao.baidu.com/link?url=qg1AcsUjhkG4gHBv8GtHDjIQuwgtLto1_eyeinBx-b8TW9HAcYRR1zizL8vTDPTAjLwHPOdz7NcwJun-HyJXeK