Java后台+数据库+Java web前端（新手）

实现简单页面上对数据的增删改查：Java后台+数据库表+Jsp前端网页设计

项目下载链接：https://pan.baidu.com/s/1UvZ5fzFjxU-GELo9Th3nNg
提取码：kvmc

GitHub源码下载：https://github.com/yishengxiaobai/Java_Course

这里做一个简单的学生课程信息管理系统，做之前一定要先有自己的思路，要不然对新手来说，很容易乱的。

通过本系统，同学们可以添加，删除，查询与修改课程上课地点和课程老师以及课程名称等信息。

运行截图：

数据库设计：

首页：

课程信息录入：

课程信息修改：

课程信息删除：（先查找后删除）

课程信息查询：

另有一完整的代码可供参考，网页版记账本，链接https://www.cnblogs.com/sengzhao666/p/10449534.html

一.建立项目

1. 首先新建一个名为Course的Dynamic Web Project

取完名直接点击完成，或者一直下一步直到完成。

2. 程序分五层

Dao:底层程序

Entity：实体层

Servlet：将界面与底层程序联系起来

Service：可以理解为servlet层与dao层的中转层

Util:连接数据库

注意servlet层不是建立类，而是建立一个Servlet；其他包下均为类。

 二.数据库设计

三.系统功能分析

1. 添加

需要一个界面add.jsp

2. 删除

首先需要根据名称查找；deletebyName.jsp

查找后列出结果，删除；delete.jsp

3. 修改

首先列出所有数据；list.jsp

修改界面；update.jsp

4. 查询

查询界面；select.jsp(模糊查询)

显示查询结果界面；selectlist.jsp

四．实现增删改查四项基本功能（以添加功能为例，其他思路相同）

功能解析：

add界面得到数据；

servlet层获得数据；

Service层传递给dao底层程序；

最后dao层执行sql语句：

String sql = "insert into course(name, teacher, classroom) values('" + course.getName() + "','" + course.getTeacher() + "','" + course.getClassroom() + "')";

将数据添加进数据库。

注：推荐写程序时编写顺序也这么来：先想好系统功能，然后编写前端jsp再一步一步往下推。

程序详解：

添加界面add.jsp得到用户键入的数据；

界面执行通过后，action="courseServlet?method=add"  三目运算符将method赋值为add；

Servlet层得到method，判断method值；

String method = req.getParameter("method");
        if ("add".equals(method)) {
            add(req, resp);
        }

执行add函数。

servlet层add函数获得界面数据：

String name = req.getParameter("name");
String teacher = req.getParameter("teacher");
String classroom = req.getParameter("classroom");
Course course= new Course(name, teacher, classroom);

调用service层函数：

 if(service.add(course)) {
            req.setAttribute("message", "添加成功");//setAttribute方法用于将内容保存在对象中，传到下一个页面中
            req.getRequestDispatcher("add.jsp").forward(req,resp);//getRequestDispatcher方法用于进入下一个页面
        }

Service层传递给dao底层。

public  boolean add(Course course) {
        boolean bean=false;
        if(!dao.rename(course.getName())) {
         //检查是否重名，否的话执行下一步
         dao.add(course);
         bean=true;
        }
        return bean;
}    

Dao层执行添加功能：

String sql = "insert into course(name, teacher, classroom) values('" + course.getName() + "','" + course.getTeacher() + "','" + course.getClassroom() + "')";

五.源代码：

实体层Course.Java:

package entity;

public class Course {

 private int id;
    private String name;
    private String teacher;
    private String classroom;
    public void setId(int id) {
     this.id=id;
 }
 public int getId() {
     return id;
 }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getTeacher() {
        return teacher;
    }
    public void setTeacher(String teacher) {
        this.teacher = teacher;
    }
    public String getClassroom() {
        return classroom;
    }
    public void setClassroom(String classroom) {
        this.classroom = classroom;
    }
   
    public Course() {}

    public Course(String name, String teacher, String classroom) {
        this.name = name;
        this.teacher = teacher;
        this.classroom = classroom;
    }
}

servlet层代码如下：

package servlet;
import java.io.IOException;
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 entity.Course;
import service.courseService;

/**
 * Servlet implementation class courseServlet
 */
@WebServlet("/courseServlet")
public class courseServlet extends HttpServlet{
    private static final long serialVersionUID = 1L;

    courseService service=new courseService();

    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        /**
         * 方法选择
         */
        req.setCharacterEncoding("utf-8");
        String method = req.getParameter("method");
        if ("add".equals(method)) {
            add(req, resp);
        } else if ("delete".equals(method)) {
            delete(req, resp);
        } else if ("update".equals(method)) {
            update(req, resp);
        } else if ("select".equals(method)) {
            select(req, resp);
        } else if ("getCoursebyName".equals(method)) {
         getCoursebyName(req, resp);
        } else if ("getCoursebyName2".equals(method)) {
         getCoursebyName2(req, resp);
        }   else if ("list".equals(method)) {
            list(req, resp);
        }
    }

    private void add(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException {
     //添加
        req.setCharacterEncoding("utf-8");
        String name = req.getParameter("name");
        String teacher = req.getParameter("teacher");
        String classroom = req.getParameter("classroom");
        Course course= new Course(name, teacher, classroom);
       
        //判断是否重名
        if(service.add(course)) {
            req.setAttribute("message", "添加成功");//setAttribute方法用于将内容保存在对象中，传到下一个页面中
            req.getRequestDispatcher("add.jsp").forward(req,resp);//getRequestDispatcher方法用于进入下一个页面
        } else {
            req.setAttribute("message", "课程名称重复，请重新录入");
            req.getRequestDispatcher("add.jsp").forward(req,resp);
        }
    }
   

    private void delete(HttpServletRequest req, HttpServletResponse resp)throws IOException, ServletException{
     // 删除
        req.setCharacterEncoding("utf-8");
        String name = req.getParameter("name");
        service.delete(name);
        req.setAttribute("message", "课程信息删除成功");
        req.getRequestDispatcher("deletebyName.jsp").forward(req,resp);
    }

    private void getCoursebyName2(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException{
     /*
      * 通过名字得到
      * 跳转至修改
      */
        req.setCharacterEncoding("utf-8");
        String name = req.getParameter("name");
        Course course =service.getCoursebyName(name);      
        req.setAttribute("course", course);
        req.getRequestDispatcher("update.jsp").forward(req,resp);
       
    }
   

    private void getCoursebyName(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException{
     /*
      * 通过名字查找
      * 跳转至删除
      */
        req.setCharacterEncoding("utf-8");
        String name = req.getParameter("name");
        Course course =service.getCoursebyName(name);
        if(course == null) {
            req.setAttribute("message", "查无此课程！");
            req.getRequestDispatcher("deletebyName.jsp").forward(req,resp);
        } else {
            req.setAttribute("course", course);
            req.getRequestDispatcher("delete.jsp").forward(req,resp);
        }
    }
   

    private void list(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException{
     //列出全部信息
        req.setCharacterEncoding("utf-8");
        List<Course> course = service.list();
        req.setAttribute("courses",course);
        req.getRequestDispatcher("list.jsp").forward(req,resp);
    }

    private void update(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException{
     //修改
        req.setCharacterEncoding("utf-8");
        String name = req.getParameter("name");
        String teacher = req.getParameter("teacher");
        String classroom = req.getParameter("classroom");
        Course course = new Course(name,teacher, classroom);       
        int k=service.update(course);
        if(k==0) {
         req.setAttribute("message", "修改失败");
   req.getRequestDispatcher("courseServlet?method=list").forward(req,resp);
        }else if(k==1){
        req.setAttribute("message", "修改成功");
        req.getRequestDispatcher("courseServlet?method=list").forward(req,resp);
        }
    }

    private void select(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException{
     //查找
        req.setCharacterEncoding("utf-8");
        String name = req.getParameter("name");
        String teacher = req.getParameter("teacher");
        String classroom = req.getParameter("classroom");
        List<Course> course = service.select(name, teacher, classroom);
        req.setAttribute("courses", course);
        req.getRequestDispatcher("selectlist.jsp").forward(req,resp);
 
    }
}

service层代码如下：

package service;

import java.util.List;

import dao.Dao;
import entity.Course;

public class courseService{
    Dao dao=new Dao();
    public  boolean add(Course course) {
        boolean bean=false;
        if(!dao.rename(course.getName())) {
         //检查是否重名，否的话执行下一步
         dao.add(course);
         bean=true;
        }
        return bean;
    }
    public void delete(String name) {
     dao.delete(name);
    }
    public int update(Course course) {
     int f=0;
  if(dao.update(course)) {
   f=1;
  }
  return f;
    }
  
    public Course getCoursebyName(String name) {
     //通过Name得到一个Course
        return dao.getCoursebyName(name);
    }
   
    public List<Course> select(String name, String teacher, String classroom) {
     //查找
        return dao.select(name, teacher, classroom);
    }

    public List<Course> list() {
     //列出表中所有信息
        return dao.list();
    }
}

Dao层代码如下：

package dao;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

import entity.Course;
import util.Shujuku;

public class Dao {
 
 /*
  * 将函数设置为Boolean类型，只返回真值或假值给service层，方便
  */
 
 public boolean rename(String name) {
  //搜索数据库表course，检查是否重名
  String sql = "select * from courses where name ='" + name + "'";
        Connection conn =Shujuku.conn() ;
        Statement st= null;
        ResultSet rs = null;
        boolean bean=false;
        try {
            st = conn.createStatement();
            rs = st.executeQuery(sql);
            while (rs.next()) {
             bean = true;
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            Shujuku.close(rs,st, conn);
        }
        return bean;
 }

 public boolean add(Course course) {
  //添加
    String sql = "insert into courses(name, teacher, classroom) values('" + course.getName() + "','" + course.getTeacher() + "','" + course.getClassroom() + "')";
       Connection conn =Shujuku.conn() ;
      Statement st= null;
       boolean bean = false;
         int a = 0;
        
         try {
             st = conn.createStatement();
             st.executeUpdate(sql);
         } catch (Exception e) {
             e.printStackTrace();
         } finally {
             Shujuku.close(st, conn);
         }
        
         if (a > 0) {
             bean = true;
         }
         return bean;
  
 }

 public boolean delete(String name) {
  // 通过名字删除
  boolean f=false;
  String sql = "delete from courses where name ='" + name + "'";//删除
  Connection conn = Shujuku.conn();
  Statement state = null;
  int a=0;
  try {
   state = conn.createStatement();
   a=state.executeUpdate(sql);
  }catch (Exception e) {
   e.printStackTrace();
  } finally {
   Shujuku.close(state, conn);
  }
  if(a>0) {
   f=true;
  }
  return f;
 }

 public boolean update(Course course) {
  // 修改
  String sql = "update courses set teacher='" + course.getTeacher() + "', classroom='" + course.getClassroom()+"'where name='"+course.getName()+"'";
  Connection conn = Shujuku.conn();
  Statement state = null;
  boolean f = false;
  int a = 0;

  try {
   state = conn.createStatement();
   a = state.executeUpdate(sql);
  } catch (SQLException e) {
   e.printStackTrace();
  } finally {
   Shujuku.close(state, conn);
  }
 
  if (a > 0) {
   f = true;
  }
  return f;
  
 }

 public Course getCoursebyName(String name) {
   String sql = "select * from courses where name ='" + name + "'";
         Connection conn =Shujuku.conn() ;
         Statement st= null;
         ResultSet rs = null;
         Course course=null;
         try {
             st = conn.createStatement();
             rs = st.executeQuery(sql);
             while (rs.next()) {
                 String teacher = rs.getString("teacher");
                 String classroom = rs.getString("classroom");
                 course = new Course(name, teacher, classroom);
             }
         } catch (Exception e) {
             e.printStackTrace();
         } finally {
             Shujuku.close(rs,st, conn);
         }
         return course;
 }

 public List<Course> select(String name, String teacher, String classroom) {
 String sql = "select * from courses where ";
   if (name !=null) {
    sql += "name like '%" + name + "% '";
   }else if(name==null) {
    sql += " ";
   }
   if (name !=null&&teacher !=null) {
             sql += "and teacher like '%" + teacher + "% '";
         }else if(name==null&&teacher !=null) {
    sql += "teacher like '%" + teacher + "% '";
   }else if(teacher==null) {
    sql += " ";
   }
   if ((name!=null||teacher !=null)&&classroom !=null) {
             sql += "and classroom like '%" + classroom + "%'";
         }else if(name==null&&teacher==null&&classroom !=null) {
    sql += "teacher like '%" + teacher + "% '";
   }else if(classroom==null) {
    sql += " ";
   }
         List<Course> list = new ArrayList<>();
         Connection conn =Shujuku.conn() ;
         Statement st= null;
         ResultSet rs = null;
         try {
             st = conn.createStatement();
             rs = st.executeQuery(sql);
             Course course=null;
             while (rs.next()) {
                 String name2 = rs.getString("name");
                 String teacher2 = rs.getString("teacher");
                 String classroom2 = rs.getString("classroom");
                 course= new Course(name2, teacher2, classroom2);
                 list.add(course);
             }
         } catch (Exception e) {
             e.printStackTrace();
         } finally {
             Shujuku.close(rs,st, conn);
         }
         return list;

 }

 public List<Course> list() {
  String sql = "select * from courses";
  List<Course> list = new ArrayList<>();
        Connection conn =Shujuku.conn() ;
        Statement st= null;
        ResultSet rs = null;
        try {
            st = conn.createStatement();
            rs = st.executeQuery(sql);
            Course course=null;
            while (rs.next()) {
                String name2 = rs.getString("name");
                String teacher2 = rs.getString("teacher");
                String classroom2 = rs.getString("classroom");
                course= new Course(name2, teacher2, classroom2);
                list.add(course);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            Shujuku.close(rs,st, conn);
        }
        return list;

 }

}

数据库连接信息放在util包内：（我这里用的是sql server 2008r2）

import java.sql.Connection;
import java.sql.DriverManager;

public class Shujuku {
     public static Connection conn(){
         String url="jdbc:sqlserver://localhost:1433;DatabaseName=YourShujukuName";//填写你的数据库名
         String userName="sa";//填写你的用户名，我的是sa
         String userPwd="tzk19991029";//填写你的密码,我的是tzk19991029
         Connection con=null;

  try{
      Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
      System.out.println("加载驱动成功！");

  }catch(Exception e){

           e.printStackTrace();

           System.out.println("加载驱动失败！");
   }
 try{
    con=DriverManager.getConnection(url,userName,userPwd);
 System.out.println("连接数据库成功！");
 }catch(Exception e){
        e.printStackTrace();
        System.out.print("SQL Server连接失败！");
  }
 return con;
}
}

二.网页部分

index.jsp是首页，代码如下：

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>首页</title>
<style >
.a{
        font-size: 26px;
        margin-top: 20px;
    }
</style>
</head>
<body>
<div align="center">
<h1 style="color: red;">课程基本信息管理系统</h1>
        <div class="a">
            <a href="add.jsp">课程信息录入</a>
        </div>
        <div class="a">
            <a href="courseServlet?method=list">课程信息修改</a>
        </div>
        <div class="a">
            <a href="deletebyName.jsp">课程信息删除</a>
        </div>
        <div class="a">
            <a href="select.jsp">课程信息查询</a>
        </div>
</div>
</body>
</html>

add.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<%
         Object message = request.getAttribute("message");
         if(message!=null && !"".equals(message)){
     
    %>
         <script type="text/javascript">
              alert("<%=request.getAttribute("message")%>");
         </script>
    <%} %>
    <div align="center">
        <h1 style="color: red;">课程信息录入</h1>
        <a href="index.jsp">返回主页</a>
        <form action="courseServlet?method=add" method="post" onsubmit="return check()">
            <div >
                课程名称<input type="text" id="name" name="name"/>
            </div>
            <div >
                任课教师<input type="text" id="teacher" name="teacher" />
            </div>
            <div >
                上课地点<input type="text" id="classroom" name="classroom" />
            </div>
            <div >
                <button type="submit" >保&nbsp;&nbsp;&nbsp;存</button>
            </div>
        </form>
    </div>
    <script type="text/javascript">
        function check() {
            var name = document.getElementById("name");;
            var teacher = document.getElementById("teacher");
            var classroom = document.getElementById("classroom");
            
            //非空
            if(name.value == '') {
                alert('课程名称为空');
                name.focus();
                return false;
            }
            if(teacher.value == '') {
                alert('教师为空');
                teacher.focus();
                return false;
            }
            if(classroom.value == '') {
                alert('上课地点为空');
                classroom.focus();
                return false;
            }
        
        }
    </script>
</body>
</html>

list.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
    <%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
<style>
    .tb, td {
        border: 1px solid black;
        font-size: 22px;
    }
</style>
</head>
<body>
<%
         Object message = request.getAttribute("message");
         if(message!=null && !"".equals(message)){

    %>
         <script type="text/javascript">
              alert("<%=request.getAttribute("message")%>");
         </script>
    <%} %>
    <div align="center">
        <h1 style="color: red;">课程信息列表</h1>
        <a href="index.jsp">返回主页</a>
        <table class="tb">
            <tr>
                <td>课程名称</td>
                <td>任课教师</td>
                <td>上课地点</td>
                <td align="center" colspan="2">操作</td>
            </tr>
            <c:forEach items="${courses}" var="item">
                <tr>
                    <td>${item.name}</td>
                    <td>${item.teacher}</td>
                    <td>${item.classroom}</td>
                    <td><a href="courseServlet?method=getCoursebyName2&name=${item.name}">修改</a></td>
                </tr>
            </c:forEach>
        </table>
    </div>
</body>
</html>

deletebyName.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>删除</title>
</head>
<body>
<%
         Object message = request.getAttribute("message");
         if(message!=null && !"".equals(message)){

    %>
         <script type="text/javascript">
              alert("<%=request.getAttribute("message")%>");
         </script>
    <%} %>
    <div align="center">
        <h1 style="color: red;">课程信息删除</h1>
        <a href="index.jsp">返回主页</a>
        <form action="courseServlet?method=getCoursebyName" method="post" onsubmit="return check()">
            <div >
                课程名称<input type="text" id="name" name="name"/>
            </div>
            <div >
                <button type="submit" class="b">查&nbsp;&nbsp;&nbsp;找</button>
            </div>
        </form>
    </div>
    <script type="text/javascript">
        function check() {
            var name = document.getElementById("name");;

            //非空
            if(name.value == '') {
                alert('课程名称为空');
                name.focus();
                return false;
            }
        }
    </script>
</body>
</html>

delete.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
<style>
 .tb, td {
  border: 1px solid black;
  font-size: 22px;
 }
</style>
</head>
<body>
<div align="center">
        <h1 style="color: red;">课程信息删除</h1>
        <a href="index.jsp">返回主页</a>
        <table class="tb">
            <tr>
                <td>课程名称</td>
                <td>${course.name}</td>
            </tr>
            <tr>
                <td>任课教师</td>
                <td>${course.teacher}</td>
            </tr>
            <tr>
                <td>上课地点</td>
                <td>${course.classroom}</td>
            </tr>
        </table>
        <div class="a">
            <a onclick="return check()" href="courseServlet?method=delete&name=${course.name}">删&nbsp;&nbsp;&nbsp;除</a>
        </div>
    </div>
    <script type="text/javascript">
        function check() {
            if (confirm("真的要删除吗？")){
                return true;
            }else{
                return false;
            }
        }
    </script>
</body>
</html>

select.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<div align="center">
        <h1 style="color: red;">课程信息查询</h1>
        <a href="index.jsp">返回主页</a>
        <form action="courseServlet?method=select" method="post" onsubmit="return check()">
            <div >
                课程名称<input type="text" id="name" name="name"/>
            </div>
            <div >
                任课教师<input type="text" id="teacher" name="teacher" />
            </div>
            <div >
                上课地点<input type="text" id="classroom" name="classroom" />
            </div>
            <div >
                <button type="submit" class="b">查&nbsp;&nbsp;&nbsp;询</button>
            </div>
        </form>
    </div>
    <script type="text/javascript">
        function check() {
            var name = document.getElementById("name");;
            var teacher = document.getElementById("teacher");
            var classroom = document.getElementById("classroom");
            
            //非空
            if(name.value == '' && teacher.value == '' && classroom.value == '') {
                alert('请填写一个条件');
                return false;
            }
        }
    </script>
</body>
</html>

selectlist.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
    <%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
<style>
 .tb, td {
  border: 1px solid black;
  font-size: 22px;
 }
</style>
</head>
<body>
<div align="center">
        <h1 style="color: red;">课程信息列表</h1>
        <a href="index.jsp">返回主页</a>
        <table class="tb">
            <tr>
                <td>课程名称</td>
                <td>任课教师</td>
                <td>上课地点</td>
            </tr>
            <!-- forEach遍历出adminBeans -->
             <c:forEach items="${courses}" var="item">
                <tr>
                    <td>${item.name}</td>
                    <td>${item.teacher}</td>
                    <td>${item.classroom}</td>
                </tr>
            </c:forEach>
        </table>
    </div>
</body>
</html>

update.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<%
         Object message = request.getAttribute("message");
         if(message!=null && !"".equals(message)){

    %>
         <script type="text/javascript">
              alert("<%=request.getAttribute("message")%>");
         </script>
    <%} %>
    <div align="center">
        <h1 style="color: red;">课程信息修改</h1>
        <a href="index.jsp">返回主页</a>
        <form action="courseServlet?method=update&name=${course.name}" method="post" onsubmit="return check()">
            <div >
                课程名称<input type="text" id="name" name="name" disabled value="${course.name}"/>
            </div>
            <div >
                任课教师<input type="text" id="teacher" name="teacher" value="${course.teacher}"/>
            </div>
            <div >
                上课地点<input type="text" id="classroom" name="classroom" value="${course.classroom}"/>
            </div>
            <button type="submit">修&nbsp;&nbsp;&nbsp;改</button>
        </form>
    </div>
    <script type="text/javascript">
        function check() {
            var name = document.getElementById("name");
            var teacher = document.getElementById("teacher");
            var classroom = document.getElementById("classroom");

            //非空
            if(teacher.value == '') {
                alert('教师为空');
                teacher.focus();
                return false;
            }
            if(classroom.value == '') {
                alert('上课地点为空');
                classroom.focus();
                return false;
            }

        }
    </script>
</body>
</html>

注意：WebContent/WEN-INF/lib包下需要放置jstl.jar包和standard.jar包。可自行去网上下载。