JAVA分级测试——选课系统（补发）

博客园似乎上传图片多了之后会出现各种问题，所以只能直接上代码了

 1 <!DOCTYPE HTML>
 2 <html lang="zh">
 3     <head>
 4         <meta charset="UTF-8">
 5         <title>石家庄铁道大学学生选课系统</title>
 6         <link rel="stylesheet" type="text/css" href="css/login&register.css">
 7         <link rel="icon" type="image/x-ico" href="images/stu.ico">
 8     </head>
 9     <body>
10         <!--Header-->
11         <header>
12             <nav>
13                 <ul>
14                     <a href="Login.html"><li>首页</li></a>
15                 </ul>
16             </nav>
17         </header>
18             
19         <!--Main-->
20         <main>
21             <div class="container">
22                 <img class="login_bg" src="images/login.png">
23                 <form  class="form" action="LoginServlet" method="post">
24                     <h3>学生选课管理系统</h3>
25                     用户类别:<select name="UserSort" size="1">
26                         <option value="1">学生</option>
27                         <option value="2">教师</option>
28                         <option value="3">管理员</option>
29                 </select>
30                     <input type="text" autofocus="autofocus" name="username" value="" placeholder="用户名" required="required">
31                     <input type="password" name="password" value=""  placeholder="密码" required="required">
32                     <input id="submit" type="submit" name="submit" value="登录">
33                     <input id="submit" type="reset" name="submit"  value="清空">
34                 </form>
35             </div>
36         </main>
37 
38         <!--Footer-->
39         <footer>
40             <div class="info">
41                 <ul>
42                     <a href="#"><li>学生选课管理系统</li></a>
43                     <a href="#"><li>帮助与反馈</li></a>
44                 </ul>
45             </div>
46             <div class="copyright">
47                 &copy; Copyright. All rights reserved. Design by <a href="http://www.github.com/Soarkey/">Soarkey</a>
48             </div>
49         </footer>
50     </body>
51 </html>

 1 <%@ page language="java" contentType="text/html; charset=UTF-8"
 2     pageEncoding="UTF-8"%>
 3 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
 4 <html>
 5 <head>
 6 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
 7 <title>Insert title here</title>
 8 <script type="text/javascript">
 9     alert("${message}"); /* 提示信息  */     
10     document.location.href='${url}'; /* 页面转换   */
11 </script>
12 </head>
13 <body>
14 
15 </body>
16 </html>

message.jsp

 1 <%@page import="bean.User"%>
 2 <%@ page language="java" contentType="text/html; charset=UTF-8"
 3     pageEncoding="UTF-8"%>
 4 <!DOCTYPE html>
 5 <html lang="zh">
 6 <head>
 7     <meta charset=UTF-8>
 8     <title>错误信息</title>
 9     <link rel="stylesheet" type="text/css" href="css/message.css">
10     <link rel="icon" type="image/x-ico" href="images/stu.ico">
11 </head>
12 <body>
13     <main>
14         <div class="message">
15             <div class="left">
16             <%
17                 //获取提示信息
18                 String info = (String) request.getAttribute("info");
19                 //如果提示信息不为空，则输出
20                 if(info != null){
21             %>
22                 <h3><%=info%></h3>
23             <%
24                 }
25                 //获取登录成功的用户信息
26                 User user = (User) session.getAttribute("user");
27                 //判断用户是否登录
28                 if(user != null){
29                     
30                 }else{
31                     //out.print("<script>alert('对不起！您还未登录！');</script>"); 
32             %>
33                 <p><%="对不起！您还未登录！"%></p>
34             <%
35                 }    
36             %>
37             </div>
38             <div class="right">
39                 <a class="relogin" href="Login.html">重新登录></a>
40             </div>
41         </div>
42     </main>
43     
44     <footer>
45         <div class="info">
46                 <ul>
47                     <a href="#"><li>学生选课管理系统</li></a>
48                     <a href="#"><li>联系我们</li></a>
49                 </ul>
50             </div>
51             <div class="copyright">
52                 &copy; Copyright. All rights reserved. Design by <a href="http://www.github.com/Soarkey/">Soarkey</a>
53             </div>
54     </footer>
55 </body>
56 </html>

error.jsp

 1 <%@page import="bean.User"%>
 2 <%@ page language="java" contentType="text/html; charset=UTF-8"
 3     pageEncoding="UTF-8"%>
 4 <!DOCTYPE html>
 5 <html>
 6 <head>
 7 <meta charset="UTF-8">
 8 <title>管理员后台界面</title>
 9 <link rel="stylesheet" type="text/css" href="css/user&admin.css">
10 <link rel="icon" type="image/x-ico" href="images/stu.ico">
11 </head>
12 <body>
13     <header>
14         <div class="title">
15             <span>管理员操作界面</span>
16         </div>
17         <nav>
18             <div class="userinfo">
19                 <ul>
20                     <li>${UNAME}</li>
21                     <li><a href="UserExitServlet">退出登录</a></li>
22                 </ul>
23             </div>
24         </nav>
25     </header>
26     
27     <main>
28         <div class="container">
29             <div class="select">
30                 <h3>请选择操作</h3>
31                 <ul id="accordion" class="accordion">
32                     <li>
33                         <div id="user-info" class="link">教师信息管理</div>
34                         <ul class="submenu">
35                             <li><a onclick="show_insert_user()">新增教师信息</a></li>                                
36                         </ul>
37                     </li>
38                     <li>
39                         <div class="link">学生信息管理</div>
40                         <ul class="submenu">
41                             <li><a onclick="show_insert_student()">新增学生信息</a></li>    
42                         </ul>
43                     </li>
44                 </ul>
45                 </div>
46                 <div id="result" class="result">
47                     <p class="welcome">欢迎使用学生选课管理系统！</p>
48                 </div>
49             </div>
50     </main>
51     
52     <footer>
53         <div class="copyright">
54             &copy; Copyright. All rights reserved. Design by <a href="http://www.github.com/Soarkey/">Soarkey</a>
55         </div>
56     </footer>
57 
58     <script src="js/jquery-3.1.1.min.js"></script>
59     <script src="js/admin.js"></script>
60 </body>
61 </html>

A_Home.jsp

 1 <%@ page language="java" contentType="text/html; charset=UTF-8"
 2     pageEncoding="UTF-8"%>
 3 <%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
 4 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
 5 <html>
 6 <head>
 7 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
 8 <title>Insert title here</title>
 9 </head>
10 <body bgcolor="#e5eecc">
11     <form name="Seekfrom"
12         action="${pageContext.request.contextPath}/ElectCourseServlet"
13         method="post" target="_self">
14         <table align="center">
15             <tr>
16                 <td align="center" colspan="4">
17                     <h3>搜索课程</h3>
18                     <hr>
19                 </td>
20             </tr>
21             <tr>
22                 <td><input name="seek" type="radio" value="模糊查询" checked>模糊查询&nbsp;
23                     <input name="seek" type="radio" value="精确查询">精确查询</td>
24                 <td width="80px"><select name="select">
25                         <option>名称</option>
26                         <option>编号</option>
27                         <option>授课教师</option>
28                 </select></td>
29                 <td><input type="text" name="name" /></td>
30                 <td align="center" colspan="2"><input type="submit"
31                     value="搜   索"></td>
32             </tr>
33         </table>
34     </form>
35     <br>
36     <table align="center" width="1000" border="1">
37         <tr>
38             <td align="center" ><b>课程信息</b></td>
39         </tr>
40     </table>
41     <table align="center" width="1000" border="1" height="120"
42         cellpadding="1" cellspacing="1">
43 
44         <tr align="center" ">
45             <td><b>编号</b></td>
46             <td><b>名称</b></td>
47             <td><b>上课教师</b></td>
48             <td><b>限制人数</b></td>
49             <td><b>可选人数</b></td>
50             <td><b>是否选修</b>
51         </tr>
52         <c:forEach items="${requestScope.list}" var="c">
53             <tr align="center" bgcolor="white">
54                 <td>${c.getCNO()}</td>
55                 <td>${c.getCName()}</td>
56                 <td>${c.getCTeacher()}</td>
57                 <td>${c.getCLimitNum()}</td>
58                 <td>${c.getCResidueNum()}</td>
59                 <td><a
60                     href="${pageContext.request.contextPath}/ElectCourseServlet?id=elect&No=${c.getCNO()}">选修</a></td>
61             </tr>
62         </c:forEach>
63     </table>
64 </body>
65 </html>

ElectCourse.jsp

 1 <%@ page language="java" contentType="text/html; charset=UTF-8"
 2     pageEncoding="UTF-8"%>
 3 <!DOCTYPE html>
 4 <html>
 5 <head>
 6 <meta charset="UTF-8">
 7 <title>Insert title here</title>
 8 <link rel="stylesheet" type="text/css" href="css/login&register.css">
 9 <link rel="icon" type="image/x-ico" href="images/stu.ico">
10 </head>
11 <body>
12 <body bgcolor="#e5eecc">
13     <form action="${pageContext.request.contextPath}/AddStudent_Servlet"
14         method="post" id="myform">
15         <h3>&nbsp;&nbsp;添加学生信息：</h3>
16         <table width="650px" border="1" align="center" cellpadding="2"
17             cellspacing="2" bgcolor="#EEE8AA">
18             <tr>
19                 <td width="150px" align="center">身&nbsp;&nbsp; 份：</td>
20                 <td>学&nbsp;&nbsp;生</td>
21             </tr>
22             <tr>
23                 <td width="150px" align="center"><label for="No">学
24                         &nbsp;&nbsp;号：</label></td>
25                 <td><input type="text" name="No" size="19" id="No" /></td>
26             </tr>
27             <tr>
28                 <td width="150px" align="center"><label for="username">姓&nbsp;&nbsp;
29                         名：</label></td>
30                 <td><input type="text" name="username" size="19" id="username" /></td>
31             </tr>
32             <tr>
33                 <td width="150px" align="center">性&nbsp;&nbsp;别：</td>
34                 <td><input type="radio" name="sex" value='男' checked>男&nbsp;
35                     <input type="radio" name="sex" value='女'>女</td>
36             </tr>
37             <tr>
38                 <td width="150px" align="center"><label for="class">班&nbsp;&nbsp;级：</label></td>
39                 <td><input type="text" name="class" size="19" id="class" /></td>
40             </tr>
41             <tr>
42                 <td width="150px" align="center"><label for="major">专&nbsp;&nbsp;业：</label></td>
43                 <td><input type="text" name="department" size="19"
44                     id="department" /></td>
45             </tr>
46             <tr>
47                 <td width="150px" align="center"><label for="password">密&nbsp;&nbsp;码：</label></td>
48                 <td><input id="password" name="password" type="password"
49                     size="20"></td>
50             </tr>
51             <tr>
52                 <td width="150px" align="center"><label for="password_2">确认新密码：</label></td>
53                 <td><input type="password" name="password_2" size="20"
54                     id="password_2" /></td>
55             </tr>
56             <tr>
57                 <td align="center" colspan="2"><input type="submit" value="添加">
58                     &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<input name="reset"
59                     type="reset" value="重 置"></td>
60             </tr>
61         </table>
62     </form>
63 </body>
64 </html>

AddStudent.jsp

 1 <%@ page language="java" contentType="text/html; charset=UTF-8"
 2     pageEncoding="UTF-8"%>
 3 <!DOCTYPE html>
 4 <html>
 5 <head>
 6 <meta charset="UTF-8">
 7 <title>学生选课界面</title>
 8 <link rel="stylesheet" type="text/css" href="css/user&admin.css">
 9 <link rel="icon" type="image/x-ico" href="images/stu.ico">
10 </head>
11 <body>
12     <header>
13         <div class="title">
14             <span>学生操作界面</span>
15         </div>
16         <nav>
17             <div class="userinfo">
18                 <ul>
19                     <li>${UNAME}</li>
20                     <li><a href="UserExitServlet">退出登录</a></li>
21                 </ul>
22             </div>
23         </nav>
24     </header>
25     
26     <main>
27         <div class="container">
28             <div class="select">
29                 <h3>请选择操作</h3>
30                 <ul id="accordion" class="accordion">
31                     <li>
32                         <div id="user-info" class="link">个人信息管理</div>
33                         <ul class="submenu">
34                             <li><a href="${pageContext.request.contextPath}/StudentInfoServlet?id=update" target="result"  onclick="$('div#result').load(this.href);return false;">修改个人信息</a></li>                                
35                         </ul>
36                     </li>
37                     <li>
38                         <div class="link">课程信息管理</div>
39                         <ul class="submenu">
40                             <li><a href="${pageContext.request.contextPath}/ElectCourseServlet?id=seekall" target="result" onclick="$('div#result').load(this.href);return false;">选课</a></li>    
41                             <li><a onclick="show_course_teacher()">查看课程信息</a></li>
42                         </ul>
43                     </li>
44                 </ul>
45                 </div>
46                 <div id="result" class="result">
47                 <p class="welcome">欢迎使用学生选课管理系统！</p>
48                 </div>
49             </div>
50     </main>
51     
52     <footer>
53         <div class="copyright">
54             &copy; Copyright. All rights reserved. Design by <a href="http://www.github.com/Soarkey/">Soarkey</a>
55         </div>
56     </footer>
57 
58     <script src="js/jquery-3.1.1.min.js"></script>
59     <script src="js/admin.js"></script>
60 </body>
61 </html>

S_Home.jsp

 1 <%@ page language="java" contentType="text/html; charset=UTF-8"
 2     pageEncoding="UTF-8"%>
 3 <!DOCTYPE html>
 4 <html>
 5 <head>
 6 <meta charset="UTF-8">
 7 <title>教师管理界面</title>
 8 <link rel="stylesheet" type="text/css" href="css/user&admin.css">
 9 <link rel="icon" type="image/x-ico" href="images/stu.ico">
10 </head>
11 <body>
12     <header>
13         <div class="title">
14             <span>教师操作界面</span>
15         </div>
16         <nav>
17             <div class="userinfo">
18                 <ul>
19                     <li>${UNAME}</li>
20                     <li><a href="UserExitServlet">退出登录</a></li>
21                 </ul>
22             </div>
23         </nav>
24     </header>
25     
26     <main>
27         <div class="container">
28             <div class="select">
29                 <h3>请选择操作</h3>
30                 <ul id="accordion" class="accordion">
31                     <li>
32                         <div id="user-info" class="link">个人信息管理</div>
33                         <ul class="submenu">
34                             <li><a href="${pageContext.request.contextPath}/TeacherInfoServlet?id=update" target="result"  onclick="$('div#result').load(this.href);return false;">修改个人信息</a></li>                                
35                         </ul>
36                     </li>
37                     <li>
38                         <div class="link">课程信息管理</div>
39                         <ul class="submenu">
40                             <li><a onclick="show_insert_course()">新增选课信息</a></li>    
41                             <li><a onclick="show_course_teacher()">查看课程信息</a></li>
42                         </ul>
43                     </li>
44                 </ul>
45                 </div>
46                 <div id="result" class="result">
47                 <p class="welcome">欢迎使用学生选课管理系统！</p>
48                 </div>
49             </div>
50     </main>
51     
52     <footer>
53         <div class="copyright">
54             &copy; Copyright. All rights reserved. Design by <a href="http://www.github.com/Soarkey/">Soarkey</a>
55         </div>
56     </footer>
57 
58     <script src="js/jquery-3.1.1.min.js"></script>
59     <script src="js/admin.js"></script>
60 </body>
61 </html>

T_Home.jsp

  1 <%@ page language="java" contentType="text/html; charset=UTF-8"
  2     pageEncoding="UTF-8"%>
  3 <%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
  4 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
  5 <html>
  6 <head>
  7 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
  8 <title>Insert title here</title>
  9 <link rel="stylesheet"
 10     href="http://jqueryvalidation.org/files/demo/site-demos.css">
 11 
 12 <script
 13     src="http://static.runoob.com/assets/jquery-validation-1.14.0/lib/jquery.js"></script>
 14 <script
 15     src="http://static.runoob.com/assets/jquery-validation-1.14.0/dist/jquery.validate.min.js"></script>
 16 <script
 17     src="http://static.runoob.com/assets/jquery-validation-1.14.0/dist/localization/messages_zh.js"></script>
 18 <script type="text/javascript">
 19     $().ready(function() {
 20         $("#myform").validate({/*表单信息验证*/
 21             rules : {
 22                 username : "required",
 23                 No : {
 24                     required : true,
 25                     digits : true
 26                 },
 27                 age : {
 28                     required : true,
 29                     digits : true
 30                 },
 31                 collage : "required",
 32                 department : "required",
 33                 password : "required",
 34                 password_2 : {
 35                     required : true,
 36                     equalTo : "#password"
 37                 }
 38             },
 39             messages : {
 40                 username : {
 41                     required : "请输入姓名",
 42                 },
 43                 No : {
 44                     required : "请输入学号",
 45                     digits : "只能输入数字串",
 46                 },
 47                 age : {
 48                     required : "请输入年龄",
 49                     digits : "只能输入数字串",
 50                 },
 51                 collage : {
 52                     required : "请输入所在学院",
 53                 },
 54                 department : {
 55                     required : "请输入所在专业",
 56                 },
 57                 password : {
 58                     required : "请输入密码",
 59                 },
 60                 password_2 : {
 61                     required : "请确认密码",
 62                     equalTo : "两次密码输入不一致",
 63                 }
 64             }
 65         });
 66     });
 67 </script>
 68 </head>
 69 <body>
 70     <form
 71         action="${pageContext.request.contextPath}/UpdateTeacherInfoServlet"
 72         method="post" id="myform">
 73         <h3>&nbsp;&nbsp;修改教师信息：</h3>
 74         <table width="650px" border="1" align="center" cellpadding="2"
 75             cellspacing="2">
 76             <tr>
 77                 <td width="150px" align="center">身&nbsp;&nbsp; 份：</td>
 78                 <td>教&nbsp;&nbsp;师</td>
 79             </tr>
 80             <tr>
 81                 <td width="150px" align="center"><label for="No">工
 82                         &nbsp;&nbsp;号：</label></td>
 83                 <td>${t.getTNo()}</td>
 84             </tr>
 85             <tr>
 86                 <td width="150px" align="center"><label for="username">姓&nbsp;&nbsp;名：</label></td>
 87                 <td><input type="text" name="username" size="19" id="username"
 88                     value="${t.getTName()}" /></td>
 89             </tr>
 90             <tr>
 91                 <td width="150px" align="center">性&nbsp;&nbsp;别：</td>
 92                 <td><input type="radio" name="sex" value='男' checked>男&nbsp;
 93                     <input type="radio" name="sex" value='女'>女</td>
 94             </tr>
 95             <tr>
 96                 <td width="150px" align="center"><label for="age">专&nbsp;&nbsp;业：</label></td>
 97                 <td><input type="text" name="major" size="19" id="age"
 98                     value="${t.getTMajor()}" /></td>
 99             </tr>
100             <tr>
101                 <td width="150px" align="center"><label for="collage">职&nbsp;&nbsp;称：</label></td>
102                 <td><input type="text" name="level" size="19" id="collage"
103                     value="${t.getTLevel()}" /></td>
104             </tr>
105             <tr>
106                 <td width="150px" align="center"><label for="password">新
107                         密 码：</label></td>
108                 <td><input id="password" name="password" type="password"
109                     size="20"></td>
110             </tr>
111             <tr>
112                 <td width="150px" align="center"><label for="password_2">确认新密码：</label></td>
113                 <td><input type="password" name="password_2" size="20"
114                     id="password_2" /></td>
115             </tr>
116             <tr>
117                 <td align="center" colspan="2"><input type="submit"
118                     value="确认修改"></td>
119             </tr>
120              <tr>
121                 <td colspan="2">
122                     <font color="red">${message}</font>
123                 </td>
124             </tr>
125         </table>
126     </form>
127 </body>
128 </html>

UpdateTeacherInfo.jsp

后台代码：

因为大部分代码都大同小异，只展示选课部分的代码

 1 package servlet;
 2 
 3 import java.io.IOException;
 4 import java.util.ArrayList;
 5 import java.util.List;
 6 
 7 import javax.servlet.ServletException;
 8 import javax.servlet.annotation.WebServlet;
 9 import javax.servlet.http.HttpServlet;
10 import javax.servlet.http.HttpServletRequest;
11 import javax.servlet.http.HttpServletResponse;
12 
13 import bean.Course;
14 import service.CService;
15 import service.EService;
16 
17 /**
18  * Servlet implementation class MyCourseServlet
19  */
20 @WebServlet("/ElectCourseServlet")
21 public class ElectCourseServlet extends HttpServlet {
22     private static final long serialVersionUID = 1L;
23        
24     /**
25      * @see HttpServlet#HttpServlet()
26      */
27     public ElectCourseServlet() {
28         super();
29         // TODO Auto-generated constructor stub
30     }
31 
32     /**
33      * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
34      */
35     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
36         // TODO Auto-generated method stub
37         String id = request.getParameter("id");
38         if (id.equals("seekall")) {// 查询所有课程分配
39             List<Course> list = new ArrayList<>();
40             list = new CService().seekAll_C(list);
41             request.setAttribute("list", list); // 把list储存在request对象中
42             request.getRequestDispatcher("/jsp/course/ElectCourse.jsp").forward(request, response);// 转到/AllBookInfo.jsp页面
43         } else if (id.equals("elect")) {// 选课
44             String cNo = request.getParameter("No"); //
45             String sNo = (String) request.getSession().getAttribute("UNAME");
46             String message = "";
47             message = new EService().elect_C(cNo, sNo, message);
48             if (message == null || message.equals("")) {
49                 request.getSession().setAttribute("message", "选课成功！");
50             } else {
51                 request.getSession().setAttribute("message", message);
52 
53             }
54             request.getSession().setAttribute("url", "ElectCourseServlet?id=seekall");
55             response.sendRedirect("Message.jsp");
56         }
57     }
58 
59     /**
60      * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
61      */
62     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
63         // TODO Auto-generated method stub
64         doGet(request, response);
65     }
66 
67 }

ElectCourseServlet.java

 1 package service;
 2 
 3 import java.util.ArrayList;
 4 import java.util.List;
 5 
 6 import bean.Course;
 7 import bean.Student;
 8 import dao.ElectCSql;
 9 import dao.MinusResidueNumSql;
10 import dao.SeekElectedSql;
11 import service.CService;
12 import service.SService;
13 
14 public class EService {
15     public String elect_C(String cNo, String sNo, String message) {
16         List<Course> list = new ArrayList<>();
17         list = new CService().seek_C("编号", "精确查询", cNo, list);// 根据课程编号获得课程名称
18         String cname = ((Course) list.toArray()[0]).getCName();
19         String tname = ((Course) list.toArray()[0]).getCTeacher();
20         List<Student> list2 = new ArrayList<>();
21         list2 = new SService().seek_S("学号", "精确查询", sNo, list2);// 根据学号获得姓名
22         String sname = ((Student) list2.toArray()[0]).getSName();
23         Boolean bool = new SeekElectedSql().seekExist_Sql(cNo, sNo);// 判断该课是否选过
24         if (bool == true) {
25             message = "该课已选，请选其它课";
26             bool = false;
27         } else if (bool == false) {
28             Boolean bool2 = new MinusResidueNumSql().seekResidueNum_Sql(cNo);// 判断可选人数，并修改
29             if (bool2 == true) {
30                 bool = new ElectCSql().electC_Sql(cNo, cname, sNo, sname,tname);// 根据课程编号和学号选课
31             } else if (bool2 == false) {
32                 message = "该班学生已满，请选其它课";
33             }
34         }
35         return message;
36     }
37 }

EService.java

 1 package dao;
 2 
 3 import java.sql.Connection;
 4 import java.sql.PreparedStatement;
 5 
 6 import database.MysqlLinking;
 7 
 8 public class ElectCSql {
 9     public Boolean electC_Sql(String cNo, String cname, String sNo, String sname,String tname) {
10         (new MysqlLinking()).getLink();// 连接数据库
11         Connection conn = MysqlLinking.conn;// 得到连接数据库的Connection对象
12         Boolean bool = false;
13         if (conn != null) {
14             try {
15                 // 插入注册信息的SQL语句(使用?占位符) //添加选课信息
16                 String sql = "insert into electcourse (C_No,S_No,T_Name,C_Name,S_Name) values(?,?,?,?,?)";
17                 // 创建PreparedStatement对象
18                 PreparedStatement ps = conn.prepareStatement(sql);
19                 // 对SQL语句中的参数动态赋值
20                 ps.setString(1, cNo);
21                 ps.setString(2, sNo);
22                 ps.setString(3, tname);
23                 ps.setString(4, cname);
24                 ps.setString(5, sname);
25                 // 执行更新操作
26                 int count = ps.executeUpdate();
27                 if (count >= 1) {
28                     bool = true;
29                 }
30             } catch (Exception e) {
31                 e.printStackTrace();
32             }
33         } else {
34             // 发送数据库连接错误提示信息
35             System.out.println("数据库连接错误！");
36         }
37         return bool;
38     }
39 }

ElectCSql

 1 package dao;
 2 
 3 import java.sql.Connection;
 4 import java.sql.PreparedStatement;
 5 import java.sql.ResultSet;
 6 
 7 import database.MysqlLinking;
 8 
 9 public class MinusResidueNumSql {
10     public Boolean seekResidueNum_Sql(String cNo) {
11         (new MysqlLinking()).getLink();// 连接数据库
12         Connection conn = MysqlLinking.conn;// 得到连接数据库的Connection对象
13         Boolean bool = false;
14         if (conn != null) {
15             try {
16                 String sql = "select * from course where C_No=?"; // 根据课程编号查询课程的可选人数
17                 PreparedStatement ps = conn.prepareStatement(sql);
18                 ps.setString(1, cNo);
19                 ResultSet rs = ps.executeQuery();
20                 int residueNum = 0;
21                 while (rs.next()) {
22                     residueNum = Integer.valueOf(rs.getString("C_ResidueNum"));
23                 }
24                 if (residueNum > 0) {
25                     try {
26                         String sql_2 = "update  course set C_ResidueNum=?  where C_No=?";
27                         PreparedStatement ps_2 = conn.prepareStatement(sql_2);
28                         int re = residueNum - 1;// 课程可选人数减一
29                         ps_2.setString(1, String.valueOf(re));
30                         ps_2.setString(2, cNo);
31                         int count = ps_2.executeUpdate();
32                         if (count >= 1) {
33                             bool = true;
34                         }
35                     } catch (Exception e) {
36                         e.printStackTrace();
37                     }
38                 }
39             } catch (Exception e) {
40                 e.printStackTrace();
41             }
42         } else {
43             // 发送数据库连接错误提示信息
44             System.out.println("数据库连接错误！");
45         }
46         return bool;
47     }
48 }

MinusResidueNumSql

 1 package dao;
 2 
 3 import java.sql.Connection;
 4 import java.sql.PreparedStatement;
 5 import java.sql.ResultSet;
 6 import java.util.List;
 7 
 8 import bean.Course;
 9 import database.MysqlLinking;
10 
11 public class SeekCSql {
12     public List<Course> seekC_Sql(String select, String seek, String name, List<Course> list) {
13         (new MysqlLinking()).getLink();// 连接数据库
14         Connection conn = MysqlLinking.conn;// 得到连接数据库的Connection对象
15         if (conn != null) {
16             try {
17                 String sql = "";
18                 PreparedStatement ps = null;
19                 if (seek.equals("模糊查询")) {// 条件查询课程
20                     sql = "select * from course where " + select + " like '%" + name + "%'";
21                     ps = conn.prepareStatement(sql);
22                 } else if (seek.equals("精确查询")) {
23                     sql = "select * from course where " + select + "=?";
24                     // 创建PreparedStatement对象
25                     ps = conn.prepareStatement(sql);
26                     ps.setString(1, name);
27                 }
28                 ResultSet rs = ps.executeQuery();
29 
30                 while (rs.next()) {
31                     Course c = new Course();
32                     c.setCNO(rs.getString("C_No"));
33                     c.setCName(rs.getString("C_Name"));
34                     c.setCTeacher(rs.getString("C_Teacher"));
35                     list.add(c);
36                 }
37             } catch (Exception e) {
38                 e.printStackTrace();
39             }
40         } else {
41             // 发送数据库连接错误提示信息
42             System.out.println("数据库连接错误！");
43         }
44         return list;
45     }
46 }

SeekCSql.java

 1 package dao;
 2 
 3 import java.sql.Connection;
 4 import java.sql.PreparedStatement;
 5 import java.sql.ResultSet;
 6 
 7 import database.MysqlLinking;
 8 
 9 public class SeekElectedSql {
10     public Boolean seekExist_Sql(String cNo, String sNo) {
11         (new MysqlLinking()).getLink();// 连接数据库
12         Connection conn = MysqlLinking.conn;// 得到连接数据库的Connection对象
13         Boolean bool = false;
14         if (conn != null) {
15             try {
16                 // 插入注册信息的SQL语句(使用?占位符)
17                 String sql = "select * from electcourse where C_No=? and S_No=?";// 根据课程编号和学号判断该课是否已选
18                 // 创建PreparedStatement对象
19                 PreparedStatement ps = conn.prepareStatement(sql);
20                 // 对SQL语句中的参数动态赋值
21                 ps.setString(1, cNo);
22                 ps.setString(2, sNo);
23                 // 执行更新操作
24                 ResultSet rs = ps.executeQuery();
25                 while (rs.next()) {
26                     bool = true;
27                 }
28             } catch (Exception e) {
29                 e.printStackTrace();
30             }
31         } else {
32             // 发送数据库连接错误提示信息
33             System.out.println("数据库连接错误！");
34         }
35         return bool;
36     }
37 }

SeekElectedSql.java

整体项目结构如图：

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原文地址：https://www.cnblogs.com/wushenjiang/p/12152653.html