7.3 用戶登錄過濾案例 · JavaWeb項目開發學習手冊

# 一.創建動態web項目，名稱為FilterCase **按照以下內容創建對應的包和類** ![](http://h.yiniuedu.com/d8a45bfe2cee41f57b8e8ae3fe4f0e5f) **User.java代碼如下：** ``` package cn.baishenghua.domain; public class User { private int id; private String name; private String gender; private int age; private String address; private String qq; private String email; private String username; private String password; public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getGender() { return gender; } public void setGender(String gender) { this.gender = gender; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } public String getAddress() { return address; } public void setAddress(String address) { this.address = address; } public String getQq() { return qq; } public void setQq(String qq) { this.qq = qq; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } @Override public String toString() { return "User{" + "id=" + id + ", name='" + name + '\'' + ", gender='" + gender + '\'' + ", age=" + age + ", address='" + address + '\'' + ", qq='" + qq + '\'' + ", email='" + email + '\'' + ", username='" + username + '\'' + ", password='" + password + '\'' + '}'; } } ``` **CharacteEncodingFilter.java代碼如下：** ``` package cn.baishenghua.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.annotation.WebFilter; import javax.servlet.annotation.WebInitParam; //@WebFilter(filterName="encoding",initParams={@WebInitParam(name="encoding",value="UTF-8")}) public class CharacteEncodingFilter implements Filter { String encoding = null; public CharacteEncodingFilter() { } public void destroy() { System.out.println("CharacteEncodingFilter-destroy...."); } public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { if(encoding != null){ System.out.println("CharacteEncodingFilter-doFilter被執行...."); request.setCharacterEncoding(encoding);//request的編碼格式 response.setCharacterEncoding(encoding);//response的編碼格式 } chain.doFilter(request, response); System.out.println("CharacteEncodingFilter-doFilter回來...."); } public void init(FilterConfig fConfig) throws ServletException { encoding = fConfig.getInitParameter("encoding"); System.out.println("CharacteEncodingFilter-init...."); } } ``` **FilterDemo1.java代碼如下：** ``` package cn.baishenghua.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.annotation.WebFilter; /** * 過濾器快速入門程序 * @author Administrator * */ public class FilterDemo1 implements Filter { public FilterDemo1() { } public void destroy() { System.out.println("FilterDemo1-destroy( )......."); } public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { //對request對象請求消息增強 System.out.println("FilterDemo1被執行了......"); chain.doFilter(request, response);//放行 //對response對象響應消息增強 System.out.println("FilterDemo1回來了......"); } public void init(FilterConfig fConfig) throws ServletException { System.out.println("FilterDemo1-init( )......."); } } ``` **LoginFilter.java代碼如下：** ``` package cn.baishenghua.filter; import javax.servlet.*; import javax.servlet.annotation.WebFilter; import javax.servlet.http.HttpServletRequest; import java.io.IOException; /** * 登錄驗證的過濾器 */ @WebFilter("/*") public class LoginFilter implements Filter { public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws ServletException, IOException { System.out.println(req); //0.強制轉換 HttpServletRequest request = (HttpServletRequest) req; //1.獲取資源請求路徑 String uri = request.getRequestURI(); //2.判斷是否包含登錄相關資源路徑,要注意排除掉 css/js/圖片/驗證碼等資源 if(uri.contains("/login.jsp") || uri.contains("/loginServlet") || uri.contains("/css/") || uri.contains("/js/") || uri.contains("/fonts/") || uri.contains("/checkCodeServlet") ){ //包含，用戶就是想登錄。放行 chain.doFilter(req, resp); }else{ //不包含，需要驗證用戶是否登錄 //3.從獲取session中獲取user Object user = request.getSession().getAttribute("user"); if(user != null){ //登錄了。放行 chain.doFilter(req, resp); }else{ //沒有登錄。跳轉登錄頁面 request.setAttribute("login_msg","您尚未登錄，請登錄"); request.getRequestDispatcher("/login.jsp").forward(request,resp); } } // chain.doFilter(req, resp); } public void init(FilterConfig config) throws ServletException { } public void destroy() { } } ``` **CheckCodeServlet.java代碼如下：** ``` package cn.baishenghua.servlet; import javax.imageio.ImageIO; 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 java.awt.*; import java.awt.image.BufferedImage; import java.io.IOException; import java.util.Random; /** * 驗證碼 */ @WebServlet("/checkCodeServlet") public class CheckCodeServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException { //服務器通知瀏覽器不要緩存 response.setHeader("pragma","no-cache"); response.setHeader("cache-control","no-cache"); response.setHeader("expires","0"); //在內存中創建一個長80，寬30的圖片，默認黑色背景 //參數一：長 //參數二：寬 //參數三：顏色 int width = 80; int height = 30; BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB); //獲取畫筆 Graphics g = image.getGraphics(); //設置畫筆顏色為灰色 g.setColor(Color.GRAY); //填充圖片 g.fillRect(0,0, width,height); //產生4個隨機驗證碼，12Ey String checkCode = getCheckCode(); //將驗證碼放入HttpSession中 request.getSession().setAttribute("CHECKCODE_SERVER",checkCode); //設置畫筆顏色為黃色 g.setColor(Color.YELLOW); //設置字體的小大 g.setFont(new Font("黑體",Font.BOLD,24)); //向圖片上寫入驗證碼 g.drawString(checkCode,15,25); //將內存中的圖片輸出到瀏覽器 //參數一：圖片對象 //參數二：圖片的格式，如PNG,JPG,GIF //參數三：圖片輸出到哪里去 ImageIO.write(image,"PNG",response.getOutputStream()); } /** * 產生4位隨機字符串 */ private String getCheckCode() { String base = "0123456789ABCDEFGabcdefg"; int size = base.length(); Random r = new Random(); StringBuffer sb = new StringBuffer(); for(int i=1;i<=4;i++){ //產生0到size-1的隨機值 int index = r.nextInt(size); //在base字符串中獲取下標為index的字符 char c = base.charAt(index); //將c放入到StringBuffer中去 sb.append(c); } System.out.println(sb.toString()); return sb.toString(); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doGet(request,response); } } ``` **LoginServlet.java代碼如下：** ``` package cn.baishenghua.servlet; import cn.baishenghua.domain.User; 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; import java.lang.reflect.InvocationTargetException; import java.util.Map; @WebServlet("/loginServlet") public class LoginServlet extends HttpServlet { protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { System.out.println(request); //1.設置編碼 request.setCharacterEncoding("utf-8"); //2.獲取數據 //2.1獲取用戶填寫驗證碼 String verifycode = request.getParameter("verifycode"); //3.驗證碼校驗 HttpSession session = request.getSession(); String checkcode_server = (String) session.getAttribute("CHECKCODE_SERVER"); session.removeAttribute("CHECKCODE_SERVER");//確保驗證碼一次性 if(!checkcode_server.equalsIgnoreCase(verifycode)){ //驗證碼不正確 //提示信息 request.setAttribute("login_msg","驗證碼錯誤！"); //跳轉登錄頁面 request.getRequestDispatcher("/login.jsp").forward(request,response); return; } String username = request.getParameter("username"); String password = request.getParameter("password"); //4.封裝User對象 User user = new User(); user.setUsername(username); user.setPassword(password); User loginUser = null; if("admin".equals(username)&&"admin".equals(password)){ loginUser = user; } //6.判斷是否登錄成功 if(loginUser != null){ //登錄成功 //將用戶存入session session.setAttribute("user",loginUser); //跳轉頁面 response.sendRedirect(request.getContextPath()+"/index.jsp"); }else{ //登錄失敗 //提示信息 request.setAttribute("login_msg","用戶名或密碼錯誤！"); //跳轉登錄頁面 request.getRequestDispatcher("/login.jsp").forward(request,response); } } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request, response); } } ``` **web.xml配置文件如下：** ``` <?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" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0"> <display-name>filter</display-name> <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> <filter> <filter-name>filterDemo</filter-name> <filter-class>cn.baishenghua.filter.FilterDemo1</filter-class> </filter> <filter-mapping> <filter-name>filterDemo</filter-name> <url-pattern>/MenuManger/*</url-pattern> </filter-mapping> <filter> <filter-name>encoding</filter-name> <filter-class>cn.baishenghua.filter.CharacteEncodingFilter</filter-class> <init-param> <param-name>encoding</param-name> <param-value>UTF-8</param-value> </init-param> </filter> <filter-mapping> <filter-name>encoding</filter-name> <url-pattern>/index.jsp</url-pattern> </filter-mapping> </web-app> ``` **index.jsp界面代碼如下：** ``` <%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%> <!DOCTYPE html> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>過濾器快速入門程序</title> </head> <body> 過濾器快速入門程序 </body> </html> ``` **login.jsp界面代碼如下：** ``` <%@ page contentType="text/html;charset=UTF-8" language="java" %> <!DOCTYPE html> <html lang="zh-CN"> <head> <meta charset="utf-8"/> <meta http-equiv="X-UA-Compatible" content="IE=edge"/> <meta name="viewport" content="width=device-width, initial-scale=1"/> <title>管理員登錄</title>  <link href="css/bootstrap.min.css" rel="stylesheet">  <script src="js/jquery-2.1.0.min.js"></script>  <script src="js/bootstrap.min.js"></script> <script type="text/javascript"> //切換驗證碼 function refreshCode(){ //1.獲取驗證碼圖片對象 var vcode = document.getElementById("vcode"); //2.設置其src屬性，加時間戳 vcode.src = "${pageContext.request.contextPath}/checkCodeServlet?time="+new Date().getTime(); } </script> </head> <body> <div class="container" style="width: 400px;"> <h3 style="text-align: center;">管理員登錄</h3> <form action="${pageContext.request.contextPath}/loginServlet" method="post"> <div class="form-group"> <label for="user">用戶名：</label> <input type="text" name="username" class="form-control" id="user" placeholder="請輸入用戶名"/> </div> <div class="form-group"> <label for="password">密碼：</label> <input type="password" name="password" class="form-control" id="password" placeholder="請輸入密碼"/> </div> <div class="form-inline"> <label for="vcode">驗證碼：</label> <input type="text" name="verifycode" class="form-control" id="verifycode" placeholder="請輸入驗證碼" style="width: 120px;"/> <a href="javascript:refreshCode();"> <img src="${pageContext.request.contextPath}/checkCodeServlet" title="看不清點擊刷新" id="vcode"/> </a> </div> <hr/> <div class="form-group" style="text-align: center;"> <input class="btn btn btn-primary" type="submit" value="登錄"> </div> </form>  <div class="alert alert-warning alert-dismissible" role="alert"> <button type="button" class="close" data-dismiss="alert" > <span>×</span> </button> <strong>${login_msg}</strong> </div> </div> </body> </html> ```