实验10 “学生信息管理模块的”MVC实现
一、实验目的
- 重点掌握数据库连接过程及增、删、改、查操作；
- 重点掌握Servlet的应用；
- 掌握项目的结构及组成。
二、实验演示效果 - 设项目名称为“studentmanager”,项目部署成功后，在浏览器地址栏输入如下地址：
http://localhost:8080/studentmanager/ListStudentServlet.do
弹出如图1所示页面。
图1
单击链接“新增”，弹出图2所示页面。
图2
- 在图2所示页面输入一个学生相关信息，如图3所示。
图3
3. 在图2所示页面中，单击学号为10的学生所在行的“修改”修改链接，弹出如图4所示页面，在页面上修改相关数据，如图5所示。
图4 图5
单击图5页面中的按钮“修改”，弹出如图6所示页面，观察记录10数据。
图6
3. 单击图6所示记录为10的学生所在行中的删除按钮，弹出如图7所示页面。
图7
单击图7所示页面中的“删除”按钮，弹出如图8所示页面，观察数据变更情况。
图8
三、实验任务与步骤
（一）项目结构图如图9所示。
图9
（二） 建立数据库及相关连接
- 实验任务：设计一个Web项目，实现（一）所示功能。
- 实验步骤。
【步骤1】 在MySQL中建立数据库students（编码为UTF-8），在该数据库中新建表格student，向表格中插入几条记录，脚本如下：
/*
Navicat MySQL Data Transfer
Source Server : localhost_33061
Source Server Version : 50170
Source Host : localhost:3306
Source Database : students
Target Server Type : MYSQL
Target Server Version : 50170
File Encoding : 65001
Date: 2018-09-11 09:40:37
*/
SET FOREIGN_KEY_CHECKS=0;
– Table structure for student
DROP TABLE IF EXISTS student;
CREATE TABLE student (
id int(11) NOT NULL AUTO_INCREMENT,
name varchar(20) DEFAULT NULL,
sex varchar(8) DEFAULT NULL,
age int(11) DEFAULT NULL,
grade varchar(30) DEFAULT NULL,
score float DEFAULT NULL,
PRIMARY KEY (id)
) ENGINE=InnoDB AUTO_INCREMENT=11 DEFAULT CHARSET=utf8;
– Records of student
INSERT INTO student VALUES (‘1’, ‘张转’, ‘男’, ‘20’, ‘16计算机3班’, ‘96’);
INSERT INTO student VALUES (‘2’, ‘杨和’, ‘男’, ‘22’, ‘16计算机1班’, ‘98’);
INSERT INTO student VALUES (‘4’, ‘李智’, ‘女’, ‘19’, ‘16计算机1班’, ‘90’);
INSERT INTO student VALUES (‘5’, ‘何辉’, ‘男’, ‘18’, ‘16计算机3班’, ‘88’);
INSERT INTO student VALUES (‘7’, ‘Tom’, ‘男’, ‘19’, ‘16计算机2班’, ‘87’);
INSERT INTO student VALUES (‘8’, ‘Jenny’, ‘nv’, ‘19’, ‘16计算机2班’, ‘99’);
【步骤2】新建Web项目，向项目中导入MySQL驱动程序（如：mysql-connector-java-5.1.18-bin.jar）。
【步骤3】创建实体类
实体类与数据库表student进行映射，创建一个实体类student.java，其属性与数据库表student的字段对应，程序需要获取数据库表student中的数据，然后存放到该实体类的实例中（即对象中）。实体类Student.java对应代码如代码1所示。
代码1：Student.java
package entity;
public class Student {
public int id;
public String name;
public String sex;
public String grade;
public int age;
public float score;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public String getGrade() {
return grade;
}
public void setGrade(String grade) {
this.grade = grade;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public float getScore() {
return score;
}
public void setScore(float score) {
this.score = score;
}
}
注意：实体类的类型与个数与数据库表student的字段个数与类型对应。
【步骤4】设计访问数据库的工具类JavaBean（Dbconn.java）代码如代码2所示。
代码2：Dbconn.java
package dbutil;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class Dbconn {
private Connection conn;
public Connection getConnection() throws SQLException{
try {
Class.forName("com.mysql.jdbc.Driver");
conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/students?useUnicode=true&characterEncoding=utf8","root","");
} catch (ClassNotFoundException e) {
System.out.println("连接异常！");
e.printStackTrace();
}
return conn;
}
public void closeAll(Connection conn,Statement stat,ResultSet rs){
if(rs!=null){
try {
rs.close();
} catch (SQLException e) {
e.printStackTrace();
}finally{
if(stat!=null){
try {
stat.close();
} catch (SQLException e) {
e.printStackTrace();
}finally{
if(conn!=null){
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
}
}
}
}
【步骤5】设计访问数据库的业务逻辑类（StudentModel.java），包括对数据库的增删改查操作,参考代码如代码3所示。
代码3：StudentModel.java
package model;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import dbutil.Dbconn;
import entity.Student;
public class StudentModel {
private static PreparedStatement ps;
private static ResultSet rs;
static Dbconn s=new Dbconn();
public List search(){
List studentlist = null;
String sql = "select * from student";
try {
Connection conn=s.getConnection();
ps = conn.prepareStatement(sql);
rs = ps.executeQuery();
studentlist = new ArrayList();
while(rs.next()){
Student student = new Student();
student.setId(rs.getInt("id"));
student.setName(rs.getString("name"));
student.setAge(rs.getInt("age"));
student.setSex(rs.getString("sex"));
student.setGrade(rs.getString("grade"));
student.setScore(rs.getFloat("score"));
studentlist.add(student);
}
s.closeAll(conn,ps,rs);
} catch (Exception e) {
e.printStackTrace();
}
return studentlist;
}
public Student load(Integer id) {
Student student = null;
String sql = "select * from student where student.id = ? ";
try {
Connection conn=s.getConnection();
ps = conn.prepareStatement(sql);
ps.setInt(1, id.intValue());
rs = ps.executeQuery();
if(rs.next()){
student = new Student();
student.setId(rs.getInt("id"));
student.setName(rs.getString("name"));
student.setSex(rs.getString("sex"));
student.setAge(rs.getInt("age"));
student.setGrade(rs.getString("grade"));
student.setScore(rs.getFloat("score"));
}
s.closeAll(conn,ps,rs);
} catch (Exception e) {
e.printStackTrace();
}
return student;
}
public int update(int id,String name,String sex,int age,String grade,float score){
int a=0;
try {
Connection conn=s.getConnection();
String sql="update student set name=?,sex=?,age=?,grade=?,score=? where id=?";
ps=conn.prepareStatement(sql);
ps.setInt(6, id);
ps.setString(1, name);
ps.setString(2, sex);
ps.setInt(3,age);
ps.setString(4,grade);
ps.setFloat(5,score);
a=ps.executeUpdate();
s.closeAll(conn,ps,rs);
} catch (SQLException e) {
e.printStackTrace();
}
return a;
}
public int insert(int id,String name,String sex,int age,String grade,float score){
int a=0;
try {
Connection conn=s.getConnection();
String sql="insert student values(?,?,?,?,?,?)";
ps=conn.prepareStatement(sql);
ps.setInt(1, id);
ps.setString(2, name);
ps.setString(3, sex);
ps.setInt(4,age);
ps.setString(5,grade);
ps.setFloat(6,score);
a=ps.executeUpdate();
s.closeAll(conn,ps,rs);
} catch (SQLException e) {
e.printStackTrace();
}
return a;
}
public int delete(int id){
int a=0;
try {
Connection conn=s.getConnection();
String sql="delete from student where student.id=?";
ps=conn.prepareStatement(sql);
ps.setInt(1, id);
a=ps.executeUpdate();
s.closeAll(conn,ps,rs);
} catch (SQLException e) {
e.printStackTrace();
}
return a;
}
}
【步骤6】设计控制层的Servlet，代码如代码4到代码9所示。
代码4：Deleteservlet.java
package control;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import model.StudentModel;
public class Deleteservlet extends HttpServlet {
/**
* Constructor of the object.
*/
public Deleteservlet() {
super();
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
this.doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
int id=Integer.parseInt(request.getParameter("id"));
StudentModel model = new StudentModel();
model.delete(id);
response.sendRedirect("ListStudentServlet.do");
}
}
代码5：DoUpdateservlet.java
package control;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import model.StudentModel;
public class DoUpdateservlet extends HttpServlet {
public DoUpdateservlet() {
super();
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
this.doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
int id = Integer.parseInt(request.getParameter("id"));
String name = request.getParameter("name");
String sex = request.getParameter("sex");
int age = Integer.parseInt(request.getParameter("age"));
String grade = request.getParameter("grade");
float score = Float.parseFloat(request.getParameter("score"));
StudentModel model = new StudentModel();
model.update(id, name, sex, age, grade, score);
response.sendRedirect("ListStudentServlet.do");
}
}
代码6：Insertservlet.java
package control;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import model.StudentModel;
public class Insertservlet extends HttpServlet {
public Insertservlet() {
super();
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
int id = Integer.parseInt(request.getParameter("id"));
String name = request.getParameter("name");
String sex = request.getParameter("sex");
int age = Integer.parseInt(request.getParameter("age"));
String grade = request.getParameter("grade");
float score = Float.parseFloat(request.getParameter("score"));
StudentModel model = new StudentModel();
model.insert(id, name, sex, age, grade, score);
response.sendRedirect("ListStudentServlet.do");
}
}
代码7：ListStudentServlet.java
package control;
import java.io.IOException;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import model.StudentModel;
public class ListStudentServlet extends HttpServlet{
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
StudentModel model = new StudentModel();
List list = model.search();
request.setAttribute("studentlist", list);
request.getRequestDispatcher("/jsp/studentlist.jsp").forward(request, response);
//response.sendRedirect("jsp/studentlist.jsp");
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
this.doGet(request, response);
}
}
代码8：ShowStudentServlet.java
package control;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import model.StudentModel;
import entity.Student;
public class ShowStudentServlet extends HttpServlet{
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// 得到传入参数：学生ID
String id = request.getParameter("id");
if (null==id)
{
request.setAttribute("error", "没有该学生！");
request.getRequestDispatcher("/jsp/error.jsp").forward(request, response);
return ;
}
Integer studentId = Integer.valueOf(id);
// 调用查询方法，得到学生数据
StudentModel model = new StudentModel();
Student student = model.load(studentId);
if (null==student)
{
request.setAttribute("error", "没有指定编号的学生记录");
request.getRequestDispatcher("/jsp/error.jsp").forward(request, response);
return ;
}
// 将学生数据保存到request中
request.setAttribute("student", student);
// 转发到student.jsp
request.getRequestDispatcher("/jsp/studentshow.jsp").forward(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
this.doGet(request, response);
}
}
代码9：Updateservlet.java
package control;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import model.StudentModel;
import entity.Student;
public class Updateservlet extends HttpServlet {
/**
* Constructor of the object.
*/
public Updateservlet() {
super();
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
this.doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
// 得到传入参数：学生ID
String id = request.getParameter("id");
if (null==id)
{
request.setAttribute("error", "没有该学生！");
request.getRequestDispatcher("/jsp/error.jsp").forward(request, response);
return ;
}
Integer studentId = Integer.valueOf(id);
// 调用查询方法，得到学生数据
StudentModel model = new StudentModel();
Student student = model.load(studentId);
if (null==student)
{
request.setAttribute("error", "没有指定编号的学生记录");
request.getRequestDispatcher("/jsp/error.jsp").forward(request, response);
return ;
}
// 将管理员数据保存到request中
request.setAttribute("student", student);
// 转发到student.jsp
request.getRequestDispatcher("/jsp/studentupdate.jsp").forward(request, response);
}
}
【步骤7】配置文件web.xml,如代码10所示。
代码10：web.xml
插入学生信息
<p>学号: <input type="text" name="id"></p>
<p>姓名:
<input type="text" name="name" />
<br></p>
<p>性别:
<input type="text" name="sex" />
<br></p>
<p> 年龄:
<input type="text" name="age" />
<br></p>
<p> 班级:
<input type="text" name="grade" />
<br></p>
<p> 成绩:
<input type="text" name="score" />
<br></p>
<input type="submit" value="提交" />
<input type="reset" value="重置" />
</form>
</center>
代码12：studentlist.jsp
<%@ page language=“java” contentType=“text/html; charset=UTF-8”
pageEncoding=“GBK”%>
<%@ taglib uri=“http://java.sun.com/jsp/jstl/core” prefix=“c”%>
学生信息列表 |
新增 |
| 学号 | 姓名 | 年龄 | 班级 | 成绩 | 修改 | 删除 |
|---|---|---|---|---|---|---|
| ${studentitem.id} | ${studentitem.name} | ${studentitem.age} | ${studentitem.grade} | ${studentitem.score} | 修改 | 删除 |
代码13：studentshow.jsp
<%@ page language=“java” contentType=“text/html; charset=UTF-8”
pageEncoding=“GBK”%>
删除的学生信息
<tr>
<td align="center">
编号
</td>
<td>
${student.id}
</td>
</tr>
<tr>
<td align="center">
姓名
</td>
<td>
${student.name}
</td>
</tr>
<tr>
<td align="center">
性别
</td>
<td>
${student.sex}
</td>
</tr>
<tr>
<td align="center">
班级
</td>
<td>
${student.grade}
</td>
</tr>
<tr>
<td align="center">
年龄
</td>
<td>
${student.age}
</td>
</tr>
<tr>
<td align="center">
成绩
</td>
<td>
${student.score}
</td>
</tr>
</table>
<table align="center" width="360" border="0">
<tr>
<td align="center">
<form action="DeleteStudentservlet.do?id=${student.id}" method="post">
<input type="submit" value="删除">
</form>
</td>
<td align="center">
<form action="ListStudentServlet.do" method="post">
<input type="submit" value="返回">
</form>
</td>
</tr>
</table>
</body>
代码14：studentupdate.jsp
<%@ page language=“java” import=“java.util.,dbutil.,entity.,model.”
pageEncoding=“UTF-8”%>
<body>
<center>
<h1>
修改学生信息
</h1>
<form action="DoUpdatStudenteservlet.do?id=${student.id}" method="post">
<p>
学号: ${student.id}
</p>
<p>
姓名:
<input type="text" name="name" value="${student.name}" />
<br>
</p>
<p>
性别:
<input type="text" name="sex" value="${student.sex}" />
<br>
</p>
<p>
年龄:
<input type="text" name="age" value="${student.age}" />
<br>
</p>
<p>
班级:
<input type="text" name="grade" value="${student.grade}" />
<br>
</p>
<p>
成绩:
<input type="text" name="score" value="${student.score}" />
<br>
</p>
<input type="submit" value="修改" />
<input type="reset" value="重置" />
</form>
</center>
</body>
代码15：error.jsp
<%@ page language=“java” pageEncoding=“UTF-8”%>
出错啦，请重新再试！ |