MVC学生管理系统-阶段IV（修改学生信息）

时间：2023-03-08 22:05:46

项目源码 ：https://download.****.net/download/weixin_44718300/11091042

前期准备，主体框架，

学生列表显示  请看阶段一文章

添加学生信息  请看阶段二文章

删除学生信息 请看阶段三文章

本文是对阶段一 、二、三的增加部分，不建议跳跃查看

首先，我们捋一下思路，要想修改界面

  1. 点击修改的时候要获取被修改学生的ID ，知道去修改谁
  2. 然后拿着ID去数据库中查一下
  3. 把数据库中的数据拿出来填入表单中（数据回显/回填）
  4. 然后拿着ID和修改后的数据。进行数据库操作
  5. 提交到数据库中
  6. 返回列表

NO01：修改list.jsp

 <a href="EditServlet?sid=${stu.sid}">更新</a>

NO02：添加Servlet

public class EditServlet extends HttpServlet {

	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

		try {

			//1.接受id

			int sid = Integer.parseInt(request.getParameter("sid"));

			//2.查询学生

			StudentService service = new StudentServiceImpl();

			Student stu = service.findStudentById(sid);

			//3.显示数据

			//存数据

			request.setAttribute("stu", stu);

			//跳转

			request.getRequestDispatcher("edit.jsp").forward(request, response) ;

		} catch (SQLException e) {

			// TODO Auto-generated catch block

			e.printStackTrace();

		}

	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

		doGet(request, response);

	}

}

NO03：修改sercice和dao

//根据ID查询单个学生对象

Student findStudentById(Integer sid) throws SQLException;

@Override

public Student findStudentById(Integer sid) throws SQLException {

StudentDao dao = new StudentDaoImpl();

return dao.findStudentById(sid);

}

@Override

public Student findStudentById(Integer sid) throws SQLException {

QueryRunner runner = new QueryRunner(JDBCUtil.getDataSouce());

Student student = runner.query("select * from stu where sid = ?", new BeanHandler<Student>(Student.class),sid);

return student;

}

NO04：添加edit.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"

	pageEncoding="UTF-8"%>

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

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

<!DOCTYPE html>

<html>

<head>

<meta charset="UTF-8">

<title>修改学生</title>

</head>

<body>

	<form method="post" action="UpdateServlet">

	<input type="hidden" name ="sid" value=${stu.sid }>

		<table border="1">

			<tr>

				<td>姓名</td>

				<td><input type="text" name="sname" value="${stu.sname}"></td>

			</tr>

			<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>

			<tr>

				<td>电话</td>

				<td><input type="text" name="phone" value="${stu.phone }"></td>

			</tr>

			<tr>

				<td>生日</td>

				<td><input type="text" name="birthday" value="${stu.birthday }"></td>

			</tr>

			<tr>

				<td>爱好</td>

				<td>

				<input type="checkbox" name="hobby" value="篮球" <c:if test="${fn:contains(stu.hobby,'篮球') }">checked</c:if>>篮球

				<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="足球" <c:if test="${fn:contains(stu.hobby,'足球') }">checked</c:if>>足球

				<input type="checkbox" name="hobby" value="乒乓球" <c:if test="${fn:contains(stu.hobby,'乒乓球') }">checked</c:if>>乒乓球

				<input type="checkbox" name="hobby" value="学习" <c:if test="${fn:contains(stu.hobby,'学习') }">checked</c:if>>学习

				</td>

			</tr>

			<tr>

				<td>简介</td>

				<td><textarea name="info" rows="3" cols="20" >${stu.info }</textarea></td>

			</tr>

			<tr>

				<td colspan="2"><input type="submit" value="确认修改"></td>

			</tr>

		</table>

	</form>

</body>

</html>

NO05：添加UpdateServlet 

package com.rick.servlet;

import java.io.IOException;

import java.text.SimpleDateFormat;

import java.util.Arrays;

import java.util.Date;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import com.rick.been.Student;

import com.rick.sercive.StudentService;

import com.rick.sercive.impl.StudentServiceImpl;

public class UpdateServlet extends HttpServlet {

	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

		request.setCharacterEncoding("UTF-8");

//	    1.获得表提交上来的数据

			int sid = Integer.parseInt(request.getParameter("sid"));

			String sname = request.getParameter("sname");

			String gender = request.getParameter("gender");

			String phone = request.getParameter("phone");

			String birthday = request.getParameter("birthday");

			String info = request.getParameter("info");

			String[] h = request.getParameterValues("hobby");

			String hobby = Arrays.toString(h);

			hobby = hobby.substring(1,hobby.length()-1);

//		  2、添加到数据库

			try {

				Date birthdaydate = new SimpleDateFormat("yyyy-mm-dd").parse(birthday);

				Student student = new Student(sid,sname, gender, phone, birthdaydate, hobby, info);

				StudentService service = new StudentServiceImpl();

				service.update(student);

//		  3、跳转到列表

				request.getRequestDispatcher("StudentListServlet").forward(request, response);

			} catch (Exception e) {

				e.printStackTrace();

			}

	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

		doGet(request, response);

	}

}

NO06：在Student中添加一个有参构造，参数为全部

NO07：修改service和dao

//更新

void update(Student student) throws SQLException;

@Override

public void update(Student student) throws SQLException {

StudentDao dao = new StudentDaoImpl();

dao.update(student);

}

@Override

public void update(Student student) throws SQLException {

QueryRunner runner = new QueryRunner(JDBCUtil.getDataSouce());

runner.update("update stu set sname=?,gender=?,phone=?,birthday=?,hobby=?,info=? where sid=?",

student.getSname(),student.getGender(),student.getPhone(),

student.getBirthday(),student.getHobby(),student.getInfo(),

student.getSid());

}

NO08：

NO09：

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