217 lines
6.4 KiB
Markdown
217 lines
6.4 KiB
Markdown
本次任务是完成DAO接口实现类开发，并进行单元测试。
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## 准备工作
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### 安装Git工具
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[下载](https://static.seahi.me/2024/12/Git-2.47.1-64-bit.exe)
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### 同步项目代码
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在桌面上右键，选择 Open Git Bash here
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执行命令：
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```bash
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git clone https://git.seahi.me/用户名/stu学号.git
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```
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## 任务一：完成DAO接口的实现类
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Day 3 任务中已经完成了`StudentdAOImpl`类的实现，接下来继续完成 `TeacherDaoImpl`和`LeaveRequestDAOImpl`类，这两个类分别实现`TeacherDAO`接口和`LeaveRequestDAO`接口。
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#### StudentDAOImpl
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[StudentDAOImpl.java](https://static.seahi.me/2024/12/StudentDAOImpl.java)
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### TeacherDAOImpl
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```java
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package dao.impl;
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import dao.TeacherDAO;
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import model.Teacher;
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import util.DatabaseUtil;
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import java.sql.*;
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import java.util.ArrayList;
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import java.util.List;
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/**
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* TeacherDAO接口的实现类，提供教师数据的数据库访问操作
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* 实现了TeacherDAO接口定义的所有方法，包括基础的CRUD操作和特定的查询方法
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* 使用JDBC与数据库进行交互，所有数据库操作都包含适当的异常处理
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*/
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public class TeacherDAOImpl implements TeacherDAO {
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/**
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* 插入一条教师记录
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* 将Teacher对象的信息保存到数据库中，并获取生成的主键ID
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*
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* @param teacher 要插入的教师对象，包含教师的详细信息
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* @return 影响的行数，插入成功返回1，失败返回0
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*/
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@Override
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public int insert(Teacher teacher) {
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String sql = "INSERT INTO teachers (teacher_id, name, department, contact, password) VALUES (?, ?, ?, ?, ?)";
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try (Connection conn = DatabaseUtil.getConnection();
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PreparedStatement stmt = conn.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS)) {
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// 设置预处理语句的参数
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stmt.setString(1, teacher.getTeacherId());
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stmt.setString(2, teacher.getName());
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stmt.setString(3, teacher.getDepartment());
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stmt.setString(4, teacher.getContact());
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stmt.setString(5, teacher.getPassword());
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int affectedRows = stmt.executeUpdate();
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if (affectedRows == 0) {
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return 0;
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}
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// 获取自动生成的主键
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try (ResultSet generatedKeys = stmt.getGeneratedKeys()) {
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if (generatedKeys.next()) {
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teacher.setId(generatedKeys.getInt(1));
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}
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}
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return affectedRows;
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} catch (SQLException e) {
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e.printStackTrace();
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return 0;
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}
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}
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/**
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* 根据ID删除教师记录
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*
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* @param id 要删除的教师记录的ID
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* @return 影响的行数，删除成功返回1，失败返回0
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*/
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@Override
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public int deleteById(int id) {
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String sql = "DELETE FROM teachers WHERE id = ?";
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try (Connection conn = DatabaseUtil.getConnection();
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PreparedStatement stmt = conn.prepareStatement(sql)) {
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stmt.setInt(1, id);
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return stmt.executeUpdate();
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} catch (SQLException e) {
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e.printStackTrace();
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return 0;
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}
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}
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/**
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* 根据ID查询教师信息
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*
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* @param id 要查询的教师ID
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* @return 如果找到则返回教师对象，否则返回null
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*/
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@Override
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public Teacher findById(int id) {
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String sql = "SELECT * FROM teachers WHERE id = ?";
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try (Connection conn = DatabaseUtil.getConnection();
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PreparedStatement stmt = conn.prepareStatement(sql)) {
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stmt.setInt(1, id);
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ResultSet rs = stmt.executeQuery();
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if (rs.next()) {
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return mapResultSetToTeacher(rs);
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}
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} catch (SQLException e) {
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e.printStackTrace();
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}
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return null;
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}
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/**
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* 查询所有教师记录
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*
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* @return 包含所有教师对象的列表，如果没有记录则返回空列表
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*/
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@Override
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public List<Teacher> findAll() {
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List<Teacher> teachers = new ArrayList<>();
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String sql = "SELECT * FROM teachers";
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try (Connection conn = DatabaseUtil.getConnection();
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Statement stmt = conn.createStatement();
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ResultSet rs = stmt.executeQuery(sql)) {
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while (rs.next()) {
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teachers.add(mapResultSetToTeacher(rs));
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}
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} catch (SQLException e) {
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e.printStackTrace();
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}
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return teachers;
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}
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/**
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* 根据工号查询教师信息
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*
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* @param teacherId 要查询的教师工号
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* @return 如果找到则返回教师对象，否则返回null
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*/
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@Override
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public Teacher findByTeacherId(String teacherId) {
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String sql = "SELECT * FROM teachers WHERE teacher_id = ?";
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try (Connection conn = DatabaseUtil.getConnection();
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PreparedStatement stmt = conn.prepareStatement(sql)) {
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stmt.setString(1, teacherId);
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ResultSet rs = stmt.executeQuery();
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if (rs.next()) {
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return mapResultSetToTeacher(rs);
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}
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} catch (SQLException e) {
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e.printStackTrace();
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}
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return null;
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}
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/**
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* 将ResultSet映射为Teacher对象
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* 从结果集中提取数据并创建Teacher实例
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*
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* @param rs 包含教师数据的ResultSet对象
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* @return 映射后的Teacher对象
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* @throws SQLException 如果访问ResultSet时发生错误
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*/
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private Teacher mapResultSetToTeacher(ResultSet rs) throws SQLException {
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// TODO 补全代码（参考Day3 任务二.4）
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}
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}
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```
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### LeaveRequestDAOImpl
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源文件：[LeaveRequestDAOImpl.java](https://static.seahi.me/2024/12/LeaveRequestDAOImpl.java)
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下载后放置到合适的位置
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## 任务二：DAO实现类的单元测试
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将下列文件放置在 `src/test/dao/impl` 目录中，检查测试是否通过
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[TeacherDAOImplTest.java](https://static.seahi.me/2024/12/TeacherDAOImplTest.java)
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[LeaveRequestDAOImplTest.java](https://static.seahi.me/2024/12/LeaveRequestDAOImplTest.java)
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## 提交代码
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在项目目录中，打开 Git Bash，执行：
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```bash
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git config --global user.email "换成你的邮箱"
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git config --global user.name "换成你的用户名"
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git add .
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git commit -m "完成Day4任务"
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git push
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``` |