登錄和修改（JSP）
通過案例學習jsp的常用知識點：
1.創建一個Map集合，用於存放學生信息,將學生信息存入Map中
2.通過page將需要的包導入
3.用request.getParameter通過name得到輸入框的內容
4.session生命周期在整個會話期間，整個會話中都可以得到session中存放的信息,可以用於存放登錄學生的學號，使每個頁面都可以得到學號
5.application生命周期在整個web容器的生命期間,可以用於記錄此項目的瀏覽人數,可以得到application中存放的數據
6. 點擊修改，將所點擊的學生信息傳給另一個頁面
package entity; public class Student { private String sno;//學號 private String password;//密碼 private String name;//姓名 //構造函數 public Student(String sno, String password, String name) { this.sno = sno; this.password = password; this.name = name; } public String getSno() { return sno; } public void setSno(String sno) { this.sno = sno; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public String getName() { return name; } public void setName(String name) { this.name = name; } }
package util; import entity.Student; import java.util.HashMap; public class StudentUtil { //創建一個Map集合，用於存放學生信息 public static HashMap<String, Student> map=new HashMap<String, Student>(); static{ //向集合中傳入信息 map.put("101",new Student("101","123","lili")); map.put("102",new Student("102","123","lisa")); map.put("103",new Student("103","123","coco")); } /** * 用於檢測登錄時用戶輸入的賬戶和密碼 * @param stu * @return 返回布爾類型的數據 */ public static boolean login(Student stu){ boolean b=false; for(String s:map.keySet()){ if(map.get(s).getSno().equals(stu.getSno())&&map.get(s).getPassword().equals(stu.getPassword())){ b=true; break; } } return b; } }
index.jsp
<%-- Created by IntelliJ IDEA. User: Administrator Date: 2019/7/22 0022 Time: 上午 9:04 To change this template use File | Settings | File Templates. --%> <%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>Title</title> <style> .log{ align-content: center; text-align: center; } </style> </head> <body> <!--登錄頁面--> <form action="loginController.jsp" method="post"> <div class="log"> <h3>登錄</h3> 學號：<input type="text" name="sno"/></br> 密碼：<input type="password" name="password"/></br> <input type="submit" value="確定"/></div> </form> </body> </html>
loginController.jsp
<%@ page import="util.StudentUtil" %><%-- Created by IntelliJ IDEA. User: Administrator Date: 2019/7/22 0022 Time: 上午 9:04 To change this template use File | Settings | File Templates. --%> <%@ page contentType="text/html;charset=UTF-8" language="java" errorPage="error.jsp" %> <!--通過page將需要的包導入 --> <%@page import="entity.Student" %> <%@page import="util.StudentUtil" %> <%@ page import="javafx.application.Application" %> <html> <head> <title>Title</title> <style> table{ align-content: center; text-align: center; width: 500px; height: 200px; border: 2px solid #8ea4ff; } tr,td{ border: 2px solid #8ea4ff; } </style> </head> <body> <% String sno=request.getParameter("sno");//用request.getParameter通過name得到輸入框的內容 String password=request.getParameter("password"); Student stu=new Student(sno,password,null);//創建一個Student對象 boolean b=StudentUtil.login(stu);//調用StudentUtil的login方法檢測學號和密碼 if(b){ //session生命周期在整個會話期間，整個會話中都可以得到session中存放的信息 //此處用於存放登錄學生的學號，使每個頁面都可以得到學號 session.setAttribute("count",sno); //application生命周期在整個web容器的生命期間 //此處用於記錄此項目的瀏覽人數 //得到application中存放的數據 Object o= application.getAttribute("num"); if(o==null){//如果application中沒有數據，則向application中存入1 application.setAttribute("num",1); }else{ //如果application中已經存在數據，則存放的數據加1 int num=Integer.parseInt(o.toString()); application.setAttribute("num",num+1); } %> <h2>學生信息</h2> <h3 style="text-align: right">登錄賬號：<%=session.getAttribute("count")%></h3> <h3 style="text-align: right">瀏覽量：<%=application.getAttribute("num")%></h3> <hr> <table> <tr> <td>學號</td> <td>密碼</td> <td>姓名</td> <td></td> </tr> <% for(Student st:StudentUtil.map.values()){ %> <tr> <td><%=st.getSno()%></td> <td><%=st.getPassword()%></td> <td><%=st.getName()%></td> <!--點擊修改，將所點擊的學生信息傳給另一個頁面--> <td><a href="update.jsp?sno=<%=st.getSno()%>&&password=<%=st.getPassword()%>&&name=<%=st.getName()%>">修改</a></td> </tr> <%}%> </table>
<%}else{
//拋出異常
throw new Exception("賬戶或密碼錯誤");
}%>
</body> </html>
<%-- Created by IntelliJ IDEA. User: Administrator Date: 2019/7/22 0022 Time: 下午 5:10 To change this template use File | Settings | File Templates. --%> <%@ page contentType="text/html;charset=UTF-8" language="java" isErrorPage="true" %> <html> <head> <title>Title</title> </head> <body> <%=exception.getMessage()%> </body> </html>
update.jsp
<%-- Created by IntelliJ IDEA. User: Administrator Date: 2019/7/22 0022 Time: 上午 10:10 To change this template use File | Settings | File Templates. --%> <%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>Title</title> <style> table{ width: 400px; height: 150px; border:2px solid #8ea4ff; text-align: center; } tr,td{ border:2px solid #8ea4ff; } </style> </head> <body> <h3 style="text-align: right">登錄賬號：<%=session.getAttribute("count")%></h3> <form action="updateController.jsp" method="post"> <h2>修改信息</h2> <hr> <table> <tr> <td style="width: 30%"> 學號 </td> <td><input type="text" name="sno" value="<%=request.getParameter("sno")%>"></td> </tr> <tr> <td> 密碼 </td> <td><input type="text" name="password" value="<%=request.getParameter("password")%>"></td> </tr> <tr> <td> 姓名 </td> <td><input type="text" name="name" value="<%=request.getParameter("name")%>"></td> </tr> </table> <input type="submit" value="確定"> </form> </body> </html>
updateController.jsp
<%-- Created by IntelliJ IDEA. User: Administrator Date: 2019/7/22 0022 Time: 上午 10:18 To change this template use File | Settings | File Templates. --%> <%@ page contentType="text/html;charset=UTF-8" language="java" %> <%@page import="entity.Student" %> <%@page import="util.StudentUtil" %> <html> <head> <title>Title</title> <style> table{ align-content: center; text-align: center; width: 500px; height: 200px; border: 2px solid #8ea4ff; } tr,td{ border: 2px solid #8ea4ff; } </style> </head> <body> <% String sno=request.getParameter("sno"); String password=request.getParameter("password"); String name=request.getParameter("name"); for(String s:StudentUtil.map.keySet()){//遍歷map中所有的鍵 if(StudentUtil.map.get(s).getSno().equals(sno)){ StudentUtil.map.get(s).setSno(sno); StudentUtil.map.get(s).setPassword(password); StudentUtil.map.get(s).setName(name); } } %> 修改成功！ <h2>學生信息</h2> <h3 style="text-align: right">登錄賬號：<%=session.getAttribute("count")%></h3> <hr> <table> <tr> <td>學號</td> <td>密碼</td> <td>姓名</td> <td></td> </tr> <% for(Student st:StudentUtil.map.values()){ %> <tr> <td><%=st.getSno()%></td> <td><%=st.getPassword()%></td> <td><%=st.getName()%></td> <td><a href="update.jsp?sno=<%=st.getSno()%>&&password=<%=st.getPassword()%>&&name=<%=st.getName()%>">修改</a></td> </tr> <%}%> </table> </body> </html>
