• 第三次作业——servlet应用


    实验小组成员:

    (1)庞斌(负责环境配置、登录验证、cookie)    博客地址:https://www.cnblogs.com/XiaoPB/

    (2)郭昭杰(负责session、博客编写)    博客地址:https://www.cnblogs.com/ashes-g/

    (3)唐任峻杰 (负责过滤器)   博客地址:https://www.cnblogs.com/trjjcool/

    项目码云地址:https://gitee.com/ashes-g/j2ee

    一、配置MySQL

    主要参考博文https://www.cnblogs.com/winton-nfs/p/11524007.html进行MySQL安装与配置

    首先进入官网https://www.mysql.com/,找到DOWNLOAD标签,下载安装包

     也可以通过百度网盘下载:https://pan.baidu.com/s/1oz0TZZWkaFwoC9r2XwYGXA  提取码:2b25

    下载完成后双击开始安装并设置初始账户的密码,安装选项都选择默认选项即可

     安装完成后,在任务栏左下角搜索框内输入cmd,以管理员身份运行

     进入MySQL安装目录的bin文件夹内,输入mysqld --install安装MySQL服务

     随后输入mysqld --initialize --console命令进行初始化

     

     输入net start mysql开启MySQL的服务

    注:后续可按照上述参考博文进一步进行修改密码等操作,但我们小组使用的是可视化界面进行数据库操作,跳过了这一步

    为防止IDEA中连接数据库失败,还需要在命令行中设置时区

    参考博文:https://blog.csdn.net/liuqiker/article/details/102455077

    在命令行中依次输入命令并执行即可完成设置时区:mysql -hlocalhost -uroot -p;show variables like'%time_zone';set global time_zone = '+8:00'

    右击此电脑→高级系统设置→环境变量,在系统变量中找到Path,点击编辑并加入MySQL的安装目录

    在开始菜单找到MySQL Workbench 8.0 CE,运行MySQL的可视化操作界面

     找到红框处的加号,输入安装时设置的用户名和密码新建数据库连接

     

    完成后点击连接,在界面内找到左下角的SCHEMAS,右键选择Create Schema创建数据库

    在建立的数据库下以类似操作创建表,并录入网页登录要校验的用户名和密码数据

     MySQL相关配置完成

    二、在IDEA中的相关配置

    在IDEA中建立一个web项目,点击右上角运行的左边,选择Edit Configurations

    配置Tomcat服务器

    进入Moudles配置,在下图红框位置创建两个文件夹lib和classes

    在path选项中更改为刚才Classes文件夹的路径

    在dependencies选项中添加lib文件夹依赖

    在C:Program Files (x86)MySQLConnector J 8.0文件夹中找到驱动JAR文件,将其放入lib文件夹下

     IDEA相关配置完成

    三、用户名和密码校验

    相关代码:

    复制代码
     1 import javax.servlet.ServletContext;
     2 import javax.servlet.ServletException;
     3 import javax.servlet.annotation.WebServlet;
     4 import javax.servlet.http.*;
     5 import java.io.IOException;
     6 import java.io.PrintWriter;
     7 import java.sql.Connection;
     8 import java.sql.DriverManager;
     9 import java.sql.ResultSet;
    10 import java.sql.Statement;
    11 
    12 
    13 @WebServlet(name = "LoginServlet")
    14 public class LoginServlet extends HttpServlet {
    15     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    16                 response.setContentType("text/html; charset=UTF-8");
    17                 request.setCharacterEncoding("UTF-8");
    18 
    19         PrintWriter output=response.getWriter();
    20         String username = request.getParameter("username");
    21         String pwd = request.getParameter("pwd");
    22         //output.println("账号:  "+username+"  密码:  "+pwd+"<br>");
    23         ResultSet rs ;
    24         Statement statement = null;
    25         Connection conn =null;
    26 
    27         try {
    28             Class.forName("com.mysql.jdbc.Driver");
    29             conn = DriverManager.getConnection("jdbc:mysql://localhost:3306","root","Guozhaojie610");
    30             String sql="select * from test_db.login_chitestlist where username='"+username+"' and password='"+pwd+"'";
    31             statement =conn.createStatement();
    32             rs = statement.executeQuery(sql);
    33 
    34 
    35 
    36             if(rs.next()){
    37                 output.println("登录成功!<br>");
    38                 output.println("当前用户:  "+username+" "+" 密码:   "+pwd+"<br>");
    39 
    40                 Cookie uname = new Cookie("usname",username);
    41                 uname.setMaxAge(60*60*24*30);
    42                 response.addCookie(uname);
    43 
    44                 Cookie upwd = new Cookie("password",pwd);
    45                 upwd.setMaxAge(60*60*24*30);
    46                 response.addCookie(upwd);
    47 
    48                 //创建session
    49                 HttpSession session=request.getSession();
    50                 //获取session内的计数
    51                 Object count;
    52                 ServletContext servletContext=getServletContext();
    53                 count=servletContext.getAttribute("count");
    54                 //显示当前在线人数
    55                 output.println("当前在线人数:"+count);
    56 
    57             }else {
    58                 output.println("账号或密码错误");
    59             }
    60 
    61 
    62         } catch (Exception e) {
    63             e.printStackTrace();
    64         }
    65     }
    66 
    67     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    68 
    69     }
    70 }
    复制代码

    四、使用cookie保存登录信息

    相关代码:

    复制代码
     1 import javax.servlet.ServletException;
     2 import javax.servlet.annotation.WebServlet;
     3 import javax.servlet.http.Cookie;
     4 import javax.servlet.http.HttpServlet;
     5 import javax.servlet.http.HttpServletRequest;
     6 import javax.servlet.http.HttpServletResponse;
     7 import java.io.IOException;
     8 
     9 @WebServlet(name = "GetCookie")
    10 public class GetCookie extends HttpServlet {
    11     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    12 
    13     }
    14 
    15     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    16         Cookie coo[] = request.getCookies();//获取request中cookie集合
    17 
    18         //循环遍历
    19         for (Cookie co : coo) {
    20             System.out.println(co.getName() + ":" + co.getValue());
    21             response.getWriter().println(co.getValue());
    22         }
    23     }
    24 }
    复制代码

    五、使用session显示当前在线人数

    相关代码:

    复制代码
     1 import javax.servlet.ServletContext;
     2 import javax.servlet.annotation.WebListener;
     3 import javax.servlet.http.HttpSession;
     4 import javax.servlet.http.HttpSessionEvent;
     5 import javax.servlet.http.HttpSessionListener;
     6 
     7 @WebListener
     8 public class SessionListener implements HttpSessionListener {
     9     public static int count=0;
    10 
    11     //session创建时计数+1
    12     @Override
    13     public void sessionCreated(HttpSessionEvent hse){
    14         HttpSession httpSession=hse.getSession();
    15         ServletContext servletContext=httpSession.getServletContext();
    16         count++;
    17         servletContext.setAttribute("count",count);
    18     }
    19 
    20     //session销毁时计数-1
    21     @Override
    22     public void sessionDestroyed(HttpSessionEvent hse){
    23         HttpSession httpSession=hse.getSession();
    24         ServletContext servletContext=httpSession.getServletContext();
    25         count--;
    26         servletContext.setAttribute("count",count);
    27     }
    28 
    29 }
    复制代码

    六、使用过滤器解决中文乱码问题

    相关代码:

    复制代码
     1 import javax.servlet.*;
     2 import javax.servlet.annotation.WebFilter;
     3 import java.io.IOException;
     4 
     5 @WebFilter(filterName = "Filter")
     6 public class Filter implements javax.servlet.Filter {
     7     public void destroy() {
     8     }
     9 
    10     public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws ServletException, IOException {
    11         String encoding=req.getCharacterEncoding();
    12         System.out.println("before encoding"+encoding+"filter");
    13         encoding="utf-8";
    14         req.setCharacterEncoding(encoding);
    15         resp.setContentType("text/html;charset="+encoding);
    16         System.out.println("after encoding"+encoding+"filter");
    17         System.err.println("-----");
    18         chain.doFilter(req, resp);
    19     }
    20 
    21     public void init(FilterConfig config) throws ServletException {
    22 
    23     }
    24 
    25 }
    复制代码

    七、web.xml中相关的配置信息

    复制代码
     1 <?xml version="1.0" encoding="UTF-8"?>
     2 <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
     3          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     4          xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
     5          version="4.0">
     6     <servlet>
     7         <servlet-name>TestServlet</servlet-name>
     8         <servlet-class>TestServlet</servlet-class>
     9     </servlet>
    10     <servlet-mapping>
    11         <servlet-name>TestServlet</servlet-name>
    12         <url-pattern>/swpu</url-pattern>
    13     </servlet-mapping>
    14     <servlet>
    15         <servlet-name>LoginServlet</servlet-name>
    16         <servlet-class>LoginServlet</servlet-class>
    17     </servlet>
    18     <servlet-mapping>
    19         <servlet-name>LoginServlet</servlet-name>
    20         <url-pattern>/TEST</url-pattern>
    21     </servlet-mapping>
    22     <servlet>
    23         <servlet-name>GetCookie</servlet-name>
    24         <servlet-class>GetCookie</servlet-class>
    25     </servlet>
    26     <servlet-mapping>
    27         <servlet-name>GetCookie</servlet-name>
    28         <url-pattern>/GetCookie</url-pattern>
    29     </servlet-mapping>
    30     <listener>
    31         <listener-class>SessionListener</listener-class>
    32     </listener>
    33     <session-config>
    34         <session-timeout>3</session-timeout>
    35     </session-config>
    36     <filter>
    37         <filter-name>Filter</filter-name>
    38         <filter-class>Filter</filter-class>
    39     </filter>
    40     <filter-mapping>
    41         <filter-name>Filter</filter-name>
    42         <url-pattern>/*</url-pattern>
    43         <dispatcher>REQUEST</dispatcher>
    44         <dispatcher>FORWARD</dispatcher>
    45     </filter-mapping>
    46 
    47 </web-app>
    复制代码

    八、最终运行效果

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  • 原文地址:https://www.cnblogs.com/XiaoPB/p/13045922.html
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