1. 在第5 章课后习题2 基础上，基于jsp+servlet+javabean 实现学生表的增删改查。
数据处理交给Servlet
java
package servlet;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;
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 dao.StudentDao;
import entity.Student;
/**
* Servlet implementation class StudentServlet
*/
@WebServlet("/studentServlet")
public class StudentServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
StudentDao studentDao=new StudentDao();
/**
* @see HttpServlet#HttpServlet()
*/
public StudentServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
this.doPost(request, response);
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
request.setCharacterEncoding("UTF-8");
String op=request.getParameter("op");
if("add".equals(op)) {
Student student=new Student(request.getParameter("sno"),request.getParameter("sname"),request.getParameter("sex"));
try{
studentDao.add(student);
List<Student> studentList = studentDao.query();
//request.setAttribute("studentList",studentList);
//request.getRequestDispatcher("query.jsp").forward(request,response);
response.sendRedirect("/web1/studentServlet?op=query");
}
catch(Exception e){
response.setContentType("text/html;charset=UTF-8");
PrintWriter out=response.getWriter();
out.print("<script>alert('学号不唯一')</script>");
}
}
else if("update".equals(op)) {
Student student=new Student();
student.setId(Integer.parseInt(request.getParameter("id")));
student.setSno(request.getParameter("sno"));
student.setSname(request.getParameter("sname"));
student.setSex(request.getParameter("sex"));
try{studentDao.update(student);
List<Student> studentList = studentDao.query();
request.setAttribute("studentList",studentList);
request.getRequestDispatcher("query.jsp").forward(request,response);
}
catch(Exception e){
response.setContentType("text/html;charset=UTF-8");
PrintWriter out=response.getWriter();
out.print("<script>alert('更新失败，学号不唯一')</script>");
}
}
else if("query".equals(op)) {
List<Student> studentList;
try {
studentList = studentDao.query();
request.setAttribute("studentList",studentList);
request.getRequestDispatcher("/query.jsp").forward(request,response);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
else if("delete".equals(op)) {
try {
studentDao.delete(Integer.parseInt(request.getParameter("id")));
List<Student> studentList = studentDao.query();
request.setAttribute("studentList",studentList);
request.getRequestDispatcher("query.jsp").forward(request,response);
} catch (NumberFormatException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}jsp 只负责显示
java
<%@ page pageEncoding="UTF-8" import="java.util.*,entity.*,dao.*"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<html>
<head>
<style>
body{
text-align:center;
}
th,td{
border:2px solid gray;
text-align:center;
padding:3px 10px;
}
table{
border-collapse:collapse;
margin:10px auto;
}
#form1{
padding:20px;
display:none;
position:fixed;
top:50%;
left:50%;
width:300px;
height:200px;
z-index:1000;
margin-left:-200px;
margin-top:-200px;
background: #88f;
}
</style>
</head>
<body>
<h3><a href="javascript:add()">添加记录</a></h3>
<h2>学生信息</h2>
<table>
<tr><th>学号</th><th>姓名</th><th>性别</th><th>修改</th><th>删除</th></tr>
<c:forEach items="${studentList}" var="student" varStatus="st">
<tr>
<td>${student.sno}</td>
<td>${student.sname}</td>
<td>${student.sex}</td>
<td><a href="javascript:update(${student.id},'${student.sno}','${student.sname}','${student.sex}')">修改</a></td>
<td><a href="${pageContext.request.contextPath}/studentServlet?op=delete&id=${student.id}" onclick="return confirm('确实要删除吗？')">删除</a></td>
</tr>
</c:forEach>
</table>
<form method="post" id="form1" action="${pageContext.request.contextPath}/studentServlet">
学号<input type="text" name="sno" id="sno"/><br><br>
姓名<input type="text" name="sname" id="sname"/><br><br>
性别<input type="radio" name="sex" value="男" checked/>男<input type="radio" name="sex" value="女" />女<br><br>
<input type="hidden" name="op" value="" id="op"/>
<input type="hidden" name="id" id="id"/>
<input type="submit" value="" id="bt"/>
<input type="reset" value="重置"/>
<input type="button" value="关闭" onclick="document.getElementById('form1').style.display='none';"/>
</form>
<br>
<script>
function add(){
document.getElementById("bt").value="添加";
document.getElementById("op").value="add";
document.getElementById("form1").style.display="block";
//document.getElementById('form1').action='query.jsp';
}
function update(id,sno,sname,sex){
document.getElementById("bt").value="修改";
document.getElementById("op").value="update";
document.getElementById("id").value=id;
document.getElementById("sno").value=sno;
document.getElementById("sname").value=sname;
var sexs=document.getElementsByName("sex");
if(sex=='男'){
sexs[0].checked=true;sexs[1].checked=false;
}
else{
sexs[0].checked=false;sexs[1].checked=true;
}
document.getElementById("form1").style.display="block";
//document.getElementById('form1').action='query.jsp';
}
</script>
</body>
</html>
- 使用过滤器实现多角色登录检验
- 分别建立admin、teacher、student三个目录，里面放置各自主页面。
- 登录页面
java
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<form>
userid<input type="text"/>
userpwd<input type="text"/>
admin<input type="radio" name="role" value="admin">
teacher<input type="radio" name="role" value="teacher">
student<input type="radio" name="role" value="student">
<input type="submit" value="login"/>
</form>
<%
String role=request.getParameter("role");
if(role!=null){
session.setAttribute("role",role);
response.sendRedirect("/zdw/"+role+"/index.jsp");
}
%>
</body>
</html>- 完成登录功能的servlet，登录成功在session中存入用户名和角色名。
java
package servlet;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class servletdenglu extends HttpServlet{
public servletdenglu(){
super();
}
protected void doGet(HttpServletRequest request,HttpServletResponse response)
throws ServletException,IOException{
}
protected void doPost(HttpServletRequest request,HttpServletResponse response)
throws ServletException,IOException{
doGet(request, response);
request.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=utf-8");
HttpSession session=request.getSession();
String shenfen=request.getParameter("role");
String username=request.getParameter("userid");
if(shenfen.equals("admin")&&username!=null) {
session.setAttribute("Name",username);
response.sendRedirect("/zdw/"+shenfen+"/index.jsp");
}else if(shenfen.equals("teacher")&&username!=null){
session.setAttribute("Name",username);
response.sendRedirect("/zdw/"+shenfen+"/index.jsp");
}else if(shenfen.equals("student")&&username!=null) {
session.setAttribute("Name",username);
response.sendRedirect("/zdw/"+shenfen+"/index.jsp");
}
}
}（4）建立三个过滤器，分别拦截admin/*,teacher/*,student/*,只有以对应角色成功登录的用户才能进入。
