学生管理系统3

科技2022-08-30 105

21-学生管理系统-案例效果介绍

22-学生管理系统-登录功能的实现

23-学生管理系统-添加学生功能的实现

24-学生管理系统-查看学生功能的实现

3 综合案例-学生管理系统升级

3.1 登录功能实现

3.1.1 创建一个web项目，在 web 目录下创建一个 index.jsp。

<%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>学生管理系统首页</title> </head> <body> <%-- 获取会话域中的数据如果获取到了则显示添加和查看功能的超链接如果没获取到则显示登录功能的超链接 --%> <% Object username = session.getAttribute("username"); if(username == null) { %> <a href="/stu/login.jsp">请登录</a> <%} else {%> <a href="/stu/addStudent.jsp">添加学生</a> <a href="/stu/listStudentServlet">查看学生</a> <%}%> </body> </html>

3.1.2 在 web 目录下创建一个 login.jsp。实现登录页面

<%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>学生登录</title> </head> <body> <form action="/stu/loginStudentServlet" method="get" autocomplete="off"> 姓名：<input type="text" name="username"> <br> 密码：<input type="password" name="password"> <br> <button type="submit">登录</button> </form> </body> </html>

3.1.3 创建 LoginStudentServlet，获取用户名和密码

package com.itheima.servlet; 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.io.IOException; /* 学生登录 */ @WebServlet("/loginStudentServlet") public class LoginStudentServlet extends HttpServlet{ @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { //1.获取用户名和密码 String username = req.getParameter("username"); String password = req.getParameter("password"); //2.判断用户名 if(username == null || "".equals(username)) { //2.1用户名为空重定向到登录页面 resp.sendRedirect("/stu/login.jsp"); return; } //2.2用户名不为空将用户名存入会话域中 req.getSession().setAttribute("username",username); //3.重定向到首页index.jsp resp.sendRedirect("/stu/index.jsp"); } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { doGet(req,resp); } }

3.2添加功能实现

3.2.1 在 web 目录下创建一个 addStudent.jsp，实现添加学生的表单项

<%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>添加学生</title> </head> <body> <form action="/stu/addStudentServlet" method="get" autocomplete="off"> 学生姓名：<input type="text" name="username"> <br> 学生年龄：<input type="number" name="age"> <br> 学生成绩：<input type="number" name="score"> <br> <button type="submit">保存</button> </form> </body> </html>

3.2.2 创建 AddStudentServlet，获取学生信息并保存到文件中

package com.itheima.servlet; import com.itheima.bean.Student; 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.io.BufferedWriter; import java.io.FileWriter; import java.io.IOException; /* 实现添加功能 */ @WebServlet("/addStudentServlet") public class AddStudentServlet extends HttpServlet{ @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { //1.获取表单中的数据 String username = req.getParameter("username"); String age = req.getParameter("age"); String score = req.getParameter("score"); //2.创建学生对象并赋值 Student stu = new Student(); stu.setUsername(username); stu.setAge(Integer.parseInt(age)); stu.setScore(Integer.parseInt(score)); //3.将学生对象的数据保存到d:\\stu.txt文件中 BufferedWriter bw = new BufferedWriter(new FileWriter("d:\\stu.txt",true)); bw.write(stu.getUsername() + "," + stu.getAge() + "," + stu.getScore()); bw.newLine(); bw.close(); //4.通过定时刷新功能响应给浏览器 resp.setContentType("text/html;charset=UTF-8"); resp.getWriter().write("添加成功。2秒后自动跳转到首页..."); resp.setHeader("Refresh","2;URL=/stu/index.jsp"); } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { doGet(req,resp); } }

3.3 查看学生功能

3.3.1 创建 ListStudentServlet，读取文件中的学生信息到集合中

1、将集合添加到会话域中 2、重定向到 listStudent.jsp 页面上 package com.itheima.servlet; import com.itheima.bean.Student; 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.io.BufferedReader; import java.io.FileReader; import java.io.IOException; import java.util.ArrayList; /* 实现查看功能 */ @WebServlet("/listStudentServlet") public class ListStudentServlet extends HttpServlet { @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { //1.创建字符输入流对象，关联读取的文件 BufferedReader br = new BufferedReader(new FileReader("d:\\stu.txt")); //2.创建集合对象，用于保存Student对象 ArrayList<Student> list = new ArrayList<>(); //3.循环读取文件中的数据，将数据封装到Student对象中。再把多个学生对象添加到集合中 String line; while((line = br.readLine()) != null) { //张三,23,95 Student stu = new Student(); String[] arr = line.split(","); stu.setUsername(arr[0]); stu.setAge(Integer.parseInt(arr[1])); stu.setScore(Integer.parseInt(arr[2])); list.add(stu); } //4.将集合对象存入会话域中 req.getSession().setAttribute("students",list); //5.重定向到学生列表页面 resp.sendRedirect("/stu/listStudent.jsp"); } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { doGet(req,resp); } }

3.3.2 在 web 目录下创建一个 listStudent.jsp

<%@ page import="com.itheima.bean.Student" %> <%@ page import="java.util.ArrayList" %> <%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>查看学生</title> </head> <body> <table width="600px" border="1px"> <tr> <th>学生姓名</th> <th>学生年龄</th> <th>学生成绩</th> </tr> <% ArrayList<Student> students = (ArrayList<Student>) session.getAttribute("students"); for(Student stu : students) { %> <tr align="center"> <td><%=stu.getUsername()%></td> <td><%=stu.getAge()%></td> <td><%=stu.getScore()%></td> </tr> <%}%> </table> </body> </html>

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