自動登入簡單範例 Use servlet example－程式開發學習之路

一、建立基本專案參考：
Java建立servlet hello world example (一)

專案名稱：CookieServlet

二、首頁 index.html：
程式
<!DOCTYPE>
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<title>CookieServlet</title>
</head>
<body>
<h1>CookieServlet</h1>
<table>
<tr>
<td colspan="2" style="font-weight:bold;">測試自動登入頁:</td>
</tr>
<tr>
<td><a href="login.view">登入頁</a></td>
</tr>
</table>
</body>
</html>

三、登入頁 login.html：
程式

<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>自動登入測試</title>
</head>
<body>
<form action="login.do" method="post">
帳號：<input type="text" name="user"><br>
密碼：<input type="password" name="password"><br>
自動登入：<input type="checkbox" name="login" value="auto"><br>
<input type="submit" value="送出">
</form>
<div>測試帳號：levin 密碼：123456</div>
</body>
</html>

三、後端接收資料程式
1、登入程式
登入送出，後端接收資料程式，並判斷是否有設定自動登入。
如有勾選自動登入，將資料存入Cookie裡。

新增 LoginServlet.java :
程式

package com.test;

import java.io.IOException;

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

public class LoginServlet extends HttpServlet {
 private String AUTO_USER_KEY = "AUTO_USER_KEY";
 private String TEST_USER = "levin";
 private String TEST_PWD = "123456";

 @Override
 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  String user = request.getParameter("user");
  String passwd = request.getParameter("password");
  if (TEST_USER.equals(user) && TEST_PWD.equals(passwd)) {
   String login = request.getParameter("login");
   if ("auto".equals(login)) {
    Cookie cookie = new Cookie(AUTO_USER_KEY, TEST_USER + "||" + TEST_PWD);
    cookie.setMaxAge(7 * 24 * 60 * 60);
    response.addCookie(cookie);
   }
   request.setAttribute("user", user);
   request.getRequestDispatcher("user.view").forward(request, response);
  } else {
   response.sendRedirect("login.html");
  }
 }
}

2、是否需要自動登入
取出Cookie後，判斷是否有符合的帳號及密碼

新增程式 LoginCookieServlet.java :
程式

package com.test;

import java.io.IOException;

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

public class LoginCookieServlet extends HttpServlet {

 private String AUTO_USER_KEY = "AUTO_USER_KEY";
 private String TEST_USER = "levin";
 private String TEST_PWD = "123456";

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

  Cookie[] cookies = request.getCookies();
  if (cookies != null) {
   for (Cookie cookie : cookies) {
    if (null != cookie.getName() && null != cookie.getValue()) {
     String name = cookie.getName();
     String value = cookie.getValue();
     if (AUTO_USER_KEY.equals(name) && (TEST_USER + "||"+TEST_PWD).equals(value)) {
      // 有取得user
      request.setAttribute("user", value.toString().split("||")[0]);
      request.getRequestDispatcher("/user.view").forward(request, response);
      return;
     }
    }
   }
  }
  response.sendRedirect("login.html");
 }

 @Override
 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  processRequest(request, response);
 }

 @Override
 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  processRequest(request, response);
 }
}

3、登入成功顯示程式
新增程式 UserServlet.java：
程式

package com.test;

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

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

public class UserServlet extends HttpServlet {
 private String AUTO_USER_KEY = "AUTO_USER_KEY";
 private String TEST_USER = "levin";
 private String TEST_PWD = "123456";

 protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  response.setContentType("text/html;charset=UTF-8");

  if (request.getAttribute("user") == null) {
   response.sendRedirect("login.view");
  } else {
   PrintWriter out = response.getWriter();
   out.println("");
   out.println("");
   out.println("Servlet User Login");
   out.println("");
   out.println("");
   out.println("
" + request.getAttribute("user") + "已登入

");
   out.println("
回首頁

");

   out.println("");
   out.println("");
   out.close();
  }
 }

 @Override
 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  processRequest(request, response);
 }

 @Override
 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  processRequest(request, response);
 }
}

4、設定web.xml ：

LoginServlet mapping : /login.do
LoginCookieServlet mapping : /login.view
UserServlet mapping : /user.view

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
<display-name>CookieServlet</display-name>

<servlet>
<servlet-name>LoginServlet</servlet-name>
<servlet-class>com.test.LoginServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>LoginServlet</servlet-name>
<url-pattern>/login.do</url-pattern>
</servlet-mapping>

<servlet>
<servlet-name>UserServlet</servlet-name>
<servlet-class>com.test.UserServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>UserServlet</servlet-name>
<url-pattern>/user.view</url-pattern>
</servlet-mapping>

<servlet>
<servlet-name>LoginCookieServlet</servlet-name>
<servlet-class>com.test.LoginCookieServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>LoginCookieServlet</servlet-name>
<url-pattern>/login.view</url-pattern>
</servlet-mapping>

<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
<welcome-file>default.html</welcome-file>
<welcome-file>default.htm</welcome-file>
<welcome-file>default.jsp</welcome-file>
</welcome-file-list>
</web-app>

5、使用到相關的lib
Java jdk 1.6
Apache Tomcat 6.0
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