MVC模式_学生信息管理系统

MVC模式

1.JSP的开发模式

2.三层架构

3.学生信息管理系统

3.1数据库&Student类准备

CREATE TABLE stu(
	sid INT PRIMARY KEY AUTO_INCREMENT,
	sname VARCHAR(20),
	gender VARCHAR(5),
	phone VARCHAR(20),
	hobby VARCHAR(50),
    birthday DATE,
    synopsis VARCHAR(50),
	info VARCHAR(200)
)

public class Student {
	private int sid;
	private String sname;
	private String gender;
	private String phone;
	private String hobby;
	private String synopsis;
	private Date birthday;
    private String info;
	public Student() {
		super();
	} 

	//这里要把sid给删掉，因为sid并不是添加Student时给定的，而是数据库表自增的
	public Student(String sname, String gender, String phone, String hobby, String synopsis, Date birthday,String info) {
		super();
		this.sname = sname;
		this.gender = gender;
		this.phone = phone;
		this.hobby = hobby;
		this.synopsis = synopsis;
		this.birthday = birthday;
         this.info = info;
	}
	
	//将更新后的其它内容和sid重新封装成一个新的Student对象，更新数据库时是根据sid更新的，所以要有一个包含sid的构造方法
public Student(int sid,String sname, String gender, String phone, String hobby, String synopsis, Date birthday,String info) {
		super();
		this.sid=sid;
		this.sname = sname;
		this.gender = gender;
		this.phone = phone;
		this.hobby = hobby;
		this.synopsis = synopsis;
		this.birthday = birthday;
    	this.info = info;
}
	......get/set
}

3.2查询

3.2.1查询所有学生

3.2.1.1不带分页

  1. index.jsp

    <h3><a href="StuListServlet">显示所有学生</a></h3>

  2. StuListServlet接收请求，调用Service，再由Service调用Dao

    • StudentServiceImpl
    public class StudentServiceImpl implements StudentService {
	public List<Student> findAll() throws SQLException {
		StudentDao dao=new StudentDaoImpl();
		return dao.findAll();
	}
}
    • StudentDaoImpl
    public class StudentDaoImpl implements StudentDao {
	public List<Student> findAll() throws SQLException {//实现类的方法想要抛异常，接口的方法也要抛异常
		QueryRunner qr=new QueryRunner(JDBCUtilsConfigPro.getDataSource());
		String sql="select * from stu";
		List<Student> list=qr.query(sql, new BeanListHandler<Student>(Student.class));
		return list;
	}
}
    • StuListServlet
    //负责查询所有的学生信息，显示到stuList.jsp上
public class StuListServlet extends HttpServlet {
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		try {
			//1.查询出所有的学生
			StudentService service=new StudentServiceImpl();
			List<Student> list=service.findAll();
			//2. 把数据存储到作用域中
			request.setAttribute("list", list);
			//3. 跳转到学生列表显示页面
			request.getRequestDispatcher("stuList.jsp").forward(request, response);
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doGet(request, response);
	}
}

  3. stuList.jsp显示数据

    <table border="1" width="700px">
    <tr align="center">
        <td>编号</td>
        <td>姓名</td>
        <td>性别</td>
        <td>电话</td>
        <td>生日</td>
        <td>爱好</td>
        <td>简介</td>
        <td>操作</td>
    </tr>
    <c:forEach items="${list }" var="stu">
        <tr align="center">
            <td>${stu.sid }</td>
            <td>${stu.sname }</td>
            <td>${stu.gender }</td>
            <td>${stu.phone }</td>
            <td>${stu.birthday }</td>
            <td>${stu.hobby }</td>
            <td>${stu.synopsis }</td>
        </tr>
    </c:forEach>
</table>
3.2.1.2带分页

  1. 在index.jsp页面，点击“分页显示学生”时，向StuPageServlet发送请求，当前页currentPage设置为1，即查询第一页学生数据

    <h3><a href="StuPageServlet?currentPage=1">分页显示学生</a></h3>

  2. StuPageServlet调用Service获取分页数据，传递到stuPageList.jsp

    • StuPageServlet
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		try {
			//1.获取要显示的页码数
			int currentPage=             Integer.parseInt(request.getParameter("currentPage"));
			//2.获取该页的数据
			StudentService service=new StudentServiceImpl();
			PageBean pageBean=service.pageQuery(currentPage);
			request.setAttribute("pageBean", pageBean);
			//3.跳转界面         
            request.getRequestDispatcher("stuPageList.jsp").forward(request, response);
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}
    • PageBean
    /**
 * 这是用于封装分页的数据：
 * 		该页的学生集合数据
 * 		当前页数
 * 		总页数
 * 		每页显示的记录数
 * 		总的记录数
 */
public class PageBean<T> {
	//private List<Student> list;//该页的学生集合数据
	private List<T> list;
	//使用泛型是为了提高代码的复用性，因为以后可能会有其他类，如Teacher,Staff等
	private int currentPage;//当前页数
	private int totalPage;//总页数
	private int totalSize;//总的记录数
    //private int pageSize;//每页显示的记录数
    //可在这里设置为固定值
    public static final int pageSize=10;
    get/set ...
}
    • stuPageList.jsp
                         <c:forEach items="${pageBean.list }" var="stu"><!--request域中存的是pageBean,通过pageBean获取list-->
				<tr align="center"> 
					<td>${stu.sid }</td>
					<td>${stu.sname }</td>
					<td>${stu.gender }</td>
					<td>${stu.phone }</td>
					<td>${stu.birthday }</td>
					<td>${stu.hobby }</td>
					<td>${stu.synopsis }</td>
                                     <td>${stu.info}</td>
				</tr>
			</c:forEach>
			<tr>
				<td colspan="8">
					第${pageBean.currentPage } / ${pageBean.totalPage } 页&nbsp;&nbsp;&nbsp;
					每页 ${pageBean.pageSize } 条&nbsp;&nbsp;&nbsp;
					共 ${pageBean.totalSize } 条&nbsp;&nbsp;&nbsp;
                      <!-- 第一页时不显示“首页|上一页” -->
					<c:if test="${pageBean.currentPage !=1 }">
						<a href="StuPageServlet?currentPage=1">首页</a> | 
						<a href="StuPageServlet?currentPage=${pageBean.currentPage-1} ">上一页</a>
					</c:if>
					&nbsp;&nbsp;&nbsp;&nbsp;
					<c:forEach begin="1" end="${pageBean.totalPage }" var="i">
						<!-- 当前页时，这个页数不能点击 -->
						<c:if test="${pageBean.currentPage==i }">
							&nbsp;${i }&nbsp;
						</c:if>
						<c:if test="${pageBean.currentPage!=i }">
							&nbsp;<a href="StuPageServlet?currentPage=${i }">${i }</a>&nbsp;
						</c:if>
					</c:forEach> 
					&nbsp;&nbsp;&nbsp;&nbsp;
                      <!-- 最后一页时不显示“下一页|尾页” -->
					<c:if test="${pageBean.currentPage !=pageBean.totalPage }">
                        <!--
                            <a href="StuPageServlet?currentPage="+${PageBean.currentPage+1}>下一页</a>
                            这样写居然是错的！！！
					  -->
						<a href="StuPageServlet?currentPage=${pageBean.currentPage+1 }">下一页</a> | 
						<a href="StuPageServlet?currentPage=${pageBean.totalPage }">尾页</a>
					</c:if>
				</td>
			</tr>
3.2.1.2.1分页功能

  • 物理分页（真分页）

    只到数据库中查询一页的数据就返回。

    • 优点：内存中的数据量不会太大
    • 缺点：对数据库的访问比较频繁

  • 逻辑分页（假分页）

    把所有数据都查询出来，然后放到内存中。

    • 优点：访问速度快
    • 缺点：数据量大，可能导致内存溢出

3.2.2模糊查询

输入模糊查询条件后，调用FuzzyQueryServlet

  • stuList.jsp
<form action="FuzzyQueryServlet" method="post">
		<table border="1" width="700px">
			<tr>
				<td colspan="8">
					按姓名查询：<input type="text" name="sname"/>
					按性别查询：<select name="gender">
						      <option value="">--请选择--
									<option value="男">男
									<option value="女">女
								</select>
					<input type="submit" value="查询"/>
					<a href="addStu.jsp">添加</a>
				</td>
			</tr>
    </table>
  • FuzzyQueryServlet
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		try {
			//模糊查询提交上来的条件有中文
			request.setCharacterEncoding("UTF-8");
			//1.获取模糊查询的条件
			String sname=request.getParameter("sname");
			String gender=request.getParameter("gender");
			//2.调用service执行查询
			StudentService service=new StudentServiceImpl();
		List<Student> list=service.fuzzyQuery(sname, gender);
			request.setAttribute("list", list);
			
			//3.跳转到stuList.jsp  
request.getRequestDispatcher("stuList.jsp").forward(request, response);
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}
  • StudentDaoImpl

需要考虑的情况：1.只有姓名；2.只有性别；3.既有姓名，也有性别；4.姓名输入框可能输入空格

public List<Student> fuzzyQuery(String sname, String gender) {
        List<Student> list=null;
        String sql="select * from stu where sname like '%"+sname.replace(" ","")+"%'";
        //去掉sname中可能存在的空格
        try {
            QueryRunner queryRunner=new QueryRunner();
            Connection connection = JDBCUtils.getConn();
            if(!gender.equals("")){
                sql+="and gender=?";
                list = queryRunner.query(connection, sql, new BeanListHandler<Student>(Student.class),gender);
            }else{
                list = queryRunner.query(connection, sql, new BeanListHandler<Student>(Student.class));
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return list;
    }

3.3增加

  1. 在stuList.jsp页面点击"添加"跳转到addStu.jsp页面

    <a href="addStu.jsp">添加</a>
    • addStu.jsp
    <body>
	<h3>添加学生页面</h3>
	<form method="post" action="AddStuServlet">
		<table border="1" width="700">
			<tr>
				<td>姓名</td>
				<td><input type="text" name="sname"/></td>
			</tr>
			<tr>
				<td>性别</td>
				<td>
					<input type="radio" name="gender" value="男" />男
					<input type="radio" name="gender" value="女" />女
				</td>
			</tr>
			<tr>
				<td>电话</td>
				<td><input type="text" name="phone" /></td>
			</tr>
			<tr>
				<td>生日</td>
				<td><input type="text" name="birthday" /></td>
			</tr>
			<tr>
				<td>爱好</td>
				<td>
					<input type="checkbox" name="hobby" value="游泳"/>游泳
					<input type="checkbox" name="hobby" value="跑步"/>跑步
					<input type="checkbox" name="hobby" value="听音乐"/>听音乐
					<input type="checkbox" name="hobby" value="看书"/>看书
					<input type="checkbox" name="hobby" value="爬山"/>爬山
				</td>
			</tr>
			<tr>
				<td>简介</td>
				<td><textarea name="synopsis" rows="3" cols="30" ></textarea></td>
			</tr>
			<tr>
				<td colspan="2"><input type="submit" value="添加" /></td>
			</tr>
		</table>
	</form>
</body>

  2. 点击"添加"后，数据提交到AddStuServlet，将学生信息添加到数据库后跳转到StuListServlet，查询出所有学生后跳转到StuList.jsp

    • AddStuServlet
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		request.setCharacterEncoding("UTF-8");
		
		//1.获取系统提交上来的数据
		String sname=request.getParameter("sname");
		String gender=request.getParameter("gender");
		String phone=request.getParameter("phone");
		String birthday=request.getParameter("birthday");
		//String hobby=request.getParameter("hobby");//hobby可能有多项，这样只能得到第一项
		String[] hobbies=request.getParameterValues("hobby");
		String hobby=Arrays.toString(hobbies);//如：[跑步，游泳，爬山]
		hobby=hobby.substring(1,hobby.length()-1);//如：跑步，游泳，爬山
		String synopsis=request.getParameter("synopsis");
		
		try {
			//2.添加到数据库
			Date birthday2 = new SimpleDateFormat("yyyy-MM-dd").parse(birthday);//String--Date, 构造方法中birthday为Date类型
			Student student=new Student(sname, gender, phone, hobby, synopsis, birthday2);
			StudentService service=new StudentServiceImpl();
			service.insert(student);
			//3.跳转到stuList.jsp页面
			//先跳到StuListServlet，查询出所有学生后跳转到stuList.jsp
			request.getRequestDispatcher("StuListServlet").forward(request, response);
		} catch (Exception e) {
			e.printStackTrace();
		}	
	}

3.4删除

  1. 在stuList.jsp和stuPage.jsp添加删除按钮

    <a href="#" onclick="doDelete(${stu.sid})">删除</a>

    点击删除后，弹出对话框询问是否删除，如是，把sid传递到DeleteStuServlet

    <!-- 脚本代码，实现弹出对话框 -->
<script type="text/javascript">
	function doDelete(sid){
		var flag=confirm("是否确定删除？");
		if(flag){
			//点击确定，访问DelteStuServlet
			//window.location.href="DeleteStuServlet?sid="+sid;//在当前标签页打开超链接
			location.href="DeleteStuServlet?sid="+sid;
		}
	}
</script>

  2. DeleteStuServlet接收到sid后，执行删除，然后跳转到StuListServlet，再跳转到学生列表页

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		try {
			//1.接收sid
			int sid=Integer.parseInt(request.getParameter("sid"));
			StudentService service=new StudentServiceImpl();
			//2.执行删除
			service.delete(sid);
			//3.跳转到列表页
			request.getRequestDispatcher("StuListServlet").forward(request, response);
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}

3.5修改

  1. 在stuList.jsp添加更新按钮

    <a href="EditStuServlet?sid=${stu.sid}">修改</a>

  2. 点击修改按钮后，跳转到EditStuServlet，根据传过来的sid查询出用户信息并放到作用域中，然后跳转到editStu.jsp页面展示

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String sid = request.getParameter("sid");
        StudentService studentService=new StudentServiceImpl();
        Student student=studentService.findBySid(sid);
        request.setAttribute("stu",student);
        request.getRequestDispatcher("editStu.jsp").forward(request,response);
    }

  3. editStu.jsp展示信息如下

比较难的是性别和爱好，这两个该如何展示？

  • 性别

    用c:if标签来判断是否checked

    <%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

    	<tr>
            <td>性别</td>
            <td>
                <input type="radio" name="gender" value="男"
                       <c:if test="${stu.gender=='男'}">checked</c:if>
                >男
                <input type="radio" name="gender" value="女"
                       <c:if test="${stu.gender=='女'}">checked</c:if>
                >女
            </td>
        </tr>

  • 爱好

    爱好可能有很多个，所以用包含关系来判断。

    <%@taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions"%>

    		<tr>
            <td>爱好</td>
            <td>
                <input type="checkbox" name="hobby" value="游泳"
                       <c:if test="${fn:contains(stu.hobby,'游泳')}">checked</c:if>
                >游泳
                <input type="checkbox" name="hobby" value="篮球"
                       <c:if test="${fn:contains(stu.hobby,'篮球' )}">checked</c:if>
                >篮球
             	......
            </td>
        </tr>
  1. 用户点击提交后，提交上来的表单中是不包含sid的，所以要在editStu.jsp中手动创建一个隐藏的输入框，在这里面给定sid的值，以便提交表单时带上sid
<input type="hidden" name="sid" value="${stu.sid }"/>
  1. UpdateStuServlet接收提交上的数据并添加到数据库中，然后跳转到StuListServlet，再跳转到StuList.jsp
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		request.setCharacterEncoding("UTF-8");
		try {
			//1.获取updateStu.jsp提交上来的数据
			int sid=Integer.parseInt(request.getParameter("sid"));
			String sname=request.getParameter("sname");
			String gender=request.getParameter("gender");
			String phone=request.getParameter("phone");
			String synopsis=request.getParameter("synopsis");
			String[] hobbies=request.getParameterValues("hobby");
			String birthday=request.getParameter("birthday");
			Date date=new SimpleDateFormat("yyyy-mm-dd").parse(birthday);
			String hobby=Arrays.toString(hobbies);
			hobby=hobby.substring(1, hobby.length()-1);
			//2.添加到数据库
             //注意：这里的新建的student是带有sid的
			Student student=new Student(sid,sname, gender, phone, hobby, synopsis, date);
			StudentService service=new StudentServiceImpl();
			service.update(student);
			//3.跳转界面 
  request.getRequestDispatcher("StuListServlet").forward(request, response);
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
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原文地址：https://www.cnblogs.com/ALiWang/p/13746271.html