Java Servlet session實現登入退出

UserDao.java 從資料庫中查詢使用者名稱與密碼

// 登入

public User login(User user) throws SQLException {

QueryRunner qr = new QueryRunner(DataSourceUtils.getDataSource());

String sql = "select * from user where username = ? and password = ?";

return qr.query(sql, new BeanHandler<User>(User.class),user.getUsername(),user.getPassword());

}

UserService.java

public User login(User user){

try {

return ud.login(user);

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

return null;

}

UserServlet.java 實現登入功能

// 登入

public void login(HttpServletRequest request,

HttpServletResponse response) throws IOException, IllegalAccessException, InvocationTargetException, ServletException{

Map<String,String[]> map = request.getParameterMap();

User user = new User();

BeanUtils.populate(user,map);

if (map.get("autoLogin")!=null){

Cookie username = new Cookie("username", map.get("username")[0]);

username.setMaxAge(60*60);

Cookie password = new Cookie("password", map.get("password")[0]);

password.setMaxAge(60*60);

response.addCookie(username);

response.addCookie(password);

}

user = us.login(user);

if (user != null){

request.getSession().setAttribute("user", user);

response.sendRedirect("/ShopStore/default.jsp");

}

else{

request.setAttribute("message", " 使用者或密碼錯誤！ ");

request.getRequestDispatcher("/login.jsp").forward(request, response);

}

工具類:AutoLoginFilter.java 用來實現自動登入

package com.yinhe.web.filter;

import java.io.IOException;

import javax.servlet.Filter;

import javax.servlet.FilterChain;

import javax.servlet.FilterConfig;

import javax.servlet.ServletException;

import javax.servlet.ServletRequest;

import javax.servlet.ServletResponse;

import javax.servlet.http.Cookie;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import com.yinhe.bean.User;

import com.yinhe.service.UserService;

public class AutoLoginFilter implements Filter{

@Override

public void doFilter(ServletRequest request, ServletResponse response,

FilterChain chain) throws IOException, ServletException {

HttpServletRequest req = (HttpServletRequest)request;

HttpServletResponse resp = (HttpServletResponse)response;

// 是否已登入

if (req.getSession().getAttribute("user") == null){// 如果已登入，則啥都不幹

// 判斷 cookie 中有沒有賬戶密碼

Cookie[] cookies = req.getCookies();

if (cookies != null){

String username = "";

String userpass = "";

for (Cookie cookie : cookies) {

if (cookie.getName().equals("username")){// 找到感興趣的 cookie

username = cookie.getValue();

}

if (cookie.getName().equals("password")){// 找到感興趣的 cookie

userpass = cookie.getValue();

}

UserService us = new UserService();

User user = new User();

user.setUsername(username);

user.setPassword(userpass);

if (us.login(user) != null){

req.getSession().setAttribute("user", user);

}

chain.doFilter(request, response);

}

@Override

public void init(FilterConfig filterConfig) throws ServletException {

// TODO Auto-generated method stub

}

@Override

public void destroy() {

// TODO Auto-generated method stub

}

前臺:login.jsp 此單選框被選中下次訪問即為自動登入

<div>

<label> <input type="checkbox" name="autoLogin" > 自動登入

</label> <label> <input

type="checkbox" > 記住使用者名稱

</label>

</div>

<%@ page contentType="text/html;charset=UTF-8" language="java" %>

<html>

<head>

<style>

#nav{

height: 88px;

padding: 5px 200px;

background-color: aquamarine;

}

#logo{

float: left;

}

#userinfo{

float: right;

height: 50px;

line-height: 80px;

}

#container{

background-color: aqua;

height: 800px;

margin: 2px 200px;

font-size: xx-large;

text-align: center;

}

</style>

</head>

<body>

</div>

<%-- 不推薦使用

<%

String loginUser = (String) request.getAttribute("loginUser");

if (loginUser != null){

out.println(loginUser);

}else {

%>

<%

}

%>

--%>

<%

String loginUser = (String) session.getAttribute("loginUser");

if (loginUser != null){

out.println(loginUser);

out.println("<a href='logoutServlet'> 退出 </a>");

}else {

%>

<%

}

%>

</div>

主頁內容

<a href="info.jsp">Python ——畫一棵漂亮的櫻花樹（不同種櫻花 + 玫瑰 + 聖誕樹喔） </a>

</div>

</body>

</html>

login.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>

<html>

<head>

<style>

tr{

height:50px;

}

td{

text-align: center;

}

</style>

</head>

<body>

<%

String msg = (String)request.getAttribute("msg");

%>

<%

if(msg != null){

out.print(msg);

}

%>

<tr>

</tr>

<tr>

</tr>

<tr>

</tr>

</table>

</form>

</body>

</html>

info.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>

<html>

<head>

<title>Title</title>

<style>

#nav{

height: 88px;

padding: 5px 200px;

background-color: aquamarine;

}

#logo{

float: left;

}

#userinfo{

float: right;

height: 50px;

line-height: 80px;

}

#container{

background-color: aqua;

height: 800px;

margin: 2px 200px;

font-size: xx-large;

text-align: center;

}

</style>

</head>

<body>

</div>

<%

String loginUser = (String) session.getAttribute("loginUser");

if (loginUser != null){

out.println(loginUser);

out.println("<a href='logoutServlet'> 退出 </a>");

}else {

%>

<%

}

%>

</div>

主頁內容

</div>

</body>

</html>

Servlet02.java

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

import java.io.IOException;

@WebServlet("/myServlet02")

public class Servlet02 extends HttpServlet {

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

// 修改編碼

request.setCharacterEncoding("utf-8");// 請求過來的編碼是外匯IBhttp://www.kaifx.cn/ utf-8

response.setContentType("text/html;charset=utf-8");// 響應出去的內容，為網頁編碼 utf-8

// 獲取表單資料

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

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

// 驗證

if("aaa".equals(username) && "123".equals(password)){

// 跳轉 ( 請求轉發請求重定向 )

// 重定向：兩次請求，不能在 request 作用域享資料。

// 如果要在兩次請求或多次請求之間，進行資料共享，需要用 session

// 使用 session 步驟

// 獲取 session

HttpSession session = request.getSession();// 如果存在已有的 session ，則直接返回，否則會建立一個新的，返回。

//HttpSession session = request.getSession(true);// 同上

//HttpSession session = request.getSession(false);// 如果存在已有的 session ，則直接返回，否則返回 null 。

// 在 session 的作用域儲存資料，供後續請求使用

session.setAttribute("loginUser",username);

response.sendRedirect("index.jsp");

/* 多個頁面不推薦使用請求轉發

request.setAttribute("loginUser",username);

request.getRequestDispatcher("index.jsp").forward(request,response);

*/

}else {

// 轉發：一次請求，可以在 request 作用域中，共享資料

request.setAttribute("msg","<script>alert(' 登入失敗！ ');</script>");

// response.sendRedirect("login.jsp");

request.getRequestDispatcher("login.jsp").forward(request,response);

}

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

doPost(request, response);

}

LogoutServlet.java

import javax.servlet.ServletException;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

import java.io.IOException;

@WebServlet("/logoutServlet")

public class LogoutServlet extends HttpServlet {

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

// 退出系統

// 獲取 session

HttpSession session = request.getSession();

// 刪除 session

session.removeAttribute("loginUser");

// 跳轉到登入頁面 / 首頁

response.sendRedirect("index.jsp");

}

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

doPost(request, response);

}

web.xml

<?xml version="1.0" encoding="UTF-8"?>

<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"

version="3.1">

<welcome-file-list>

<welcome-file>index.jsp</welcome-file>

</welcome-file-list>

</web-app>

來自 “ ITPUB部落格 ” ，連結：http://blog.itpub.net/69946279/viewspace-2662508/，如需轉載，請註明出處，否則將追究法律責任。

Java Servlet session實現登入退出

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