《Spring boot从入门到实战》第七章习题答案

7.5 本章练习

创建一个Spring Boot项目，使用Thymeleaf页面模板引擎和JdbcTemplate数据持久化框架实现完整的学生信息管理模块。

答案：

application.properties 配置数据库

spring.datasource.primary.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.primary.jdbc-url=jdbc:mysql://127.0.0.1:3306/test?useSSL=false&serverTimezone=UTC
spring.datasource.primary.username=root
spring.datasource.primary.password=123456
spring.datasource.secondary.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.secondary.jdbc-url=jdbc:mysql://127.0.0.1:3306/dp_database?useSSL=false&serverTimezone=UTC
spring.datasource.secondary.username=root
spring.datasource.secondary.password=123456

JdbcTemplate 配置

package com.example.demo.config;

import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.jdbc.core.JdbcTemplate;

import javax.sql.DataSource;

@Configuration
public class DataSourceConfig {

 @Primary
 @Bean(name = "primaryDataSource")
 @Qualifier("primaryDataSource")
 @ConfigurationProperties("spring.datasource.primary")
 public DataSource primaryDataSource() {
     return DataSourceBuilder.create().build();
 }

 @Bean(name = "secondaryDataSource")
 @Qualifier("secondaryDataSource")
 @ConfigurationProperties("spring.datasource.secondary")
 public DataSource secondaryDataSource() {
     return DataSourceBuilder.create().build();
 }

 @Bean(name = "primaryJdbcTemplate")
 public JdbcTemplate primaryJdbcTemplate(@Qualifier("primaryDataSource") DataSource dataSource) {
     return new JdbcTemplate(dataSource);
 }

 @Bean(name = "secondaryJdbcTemplate")
 public JdbcTemplate secondaryJdbcTemplate(@Qualifier("secondaryDataSource") DataSource dataSource) {
     return new JdbcTemplate(dataSource);
 }

}

学生实体类 Student.java

package com.example.demo.bean;

public class Student {

 private Long id;
 private String name;
 private Integer sex;
 private Integer age;

 public Student() {
 }

 public Student(String name, int sex, int age) {
     this.name = name;
     this.sex = sex;
     this.age = age;
 }

 @Override
 public String toString() {
     return "Student{" +
             "id=" + id +
             ", name='" + name + '\'' +
             ", sex=" + sex +
             ", age=" + age +
             '}';
 }

 public Long getId() {
     return id;
 }

 public void setId(Long id) {
     this.id = id;
 }

 public String getName() {
     return name;
 }

 public void setName(String name) {
     this.name = name;
 }

 public Integer getSex() {
     return sex;
 }

 public void setSex(int sex) {
     this.sex = sex;
 }

 public Integer getAge() {
     return age;
 }

 public void setAge(int age) {
     this.age = age;
 }

}

StudentController 控制器创建 StudentController 类，处理学生管理的 HTTP 请求。

package com.example.demo.controller;

import com.example.demo.bean.Student;
import com.example.demo.service.StudentService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.*;

@Controller
@RequestMapping("/students")
public class StudentController {

 @Autowired
 private StudentService studentService;

 @GetMapping("/")
 public String getAllStudents(Model model) {
     model.addAttribute("students", studentService.listAllStudent());
     return "students/list";
 }

 @GetMapping("/add")
 public String showAddForm(Model model) {
     model.addAttribute("student", new Student());
     return "students/add";
 }

 @PostMapping("/add")
 public String addStudent(@ModelAttribute Student student) {
     studentService.insertStudent(student);
     return "redirect:/students/";
 }

 @GetMapping("/edit/{id}")
 public String showEditForm(@PathVariable Long id, Model model) {
     Student student = studentService.getStudentById(id);
     model.addAttribute("student", student);
     return "students/edit";
 }

 @PostMapping("/edit/{id}")
 public String updateStudent(@PathVariable Long id, @ModelAttribute Student student) {
     student.setId(id);
     studentService.updateStudent(student);
     return "redirect:/students/";
 }

 @GetMapping("/delete/{id}")
 public String deleteStudent(@PathVariable Long id) {
     studentService.deleteStudent(id);
     return "redirect:/students/";
 }

}

StudentService 服务类创建 StudentService 类，用于业务逻辑处理。

package com.example.demo.service;

import com.example.demo.bean.Student;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class StudentService {

 @Autowired
 @Qualifier("primaryJdbcTemplate")
 private JdbcTemplate jdbcTemplate;

 public List<Student> listAllStudent(){
     String sql = "select * from student";
     return jdbcTemplate.query(sql, new BeanPropertyRowMapper<Student>(Student.class));
 }

 public Student getStudentById(Long id){
     String sql = "select * from student where id=?";
     return jdbcTemplate.queryForObject(sql, new Object[]{id}, new BeanPropertyRowMapper<>(Student.class));
 }

 public void insertStudent(Student student){
     String sql = "insert into student(id, name, age, sex) values(?,?,?,?)";
     jdbcTemplate.update(sql,student.getId(),student.getName(),student.getAge(),student.getSex());
 }

 public void updateStudent(Student student){
     String sql = "update student set name=?,age=?,sex=? where id=?";
     jdbcTemplate.update(sql,student.getName(),student.getAge(),student.getSex(),student.getId());
 }

 public void deleteStudent(Long id){
     String sql = "delete from student where id=?";
     jdbcTemplate.update(sql,id);
 }

}

Thymeleaf 页面创建页面模板来展示学生列表、添加、编辑学生等功能。

list.html

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
    <title>学生信息管理</title>
</head>
<body>
<h1>学生信息</h1>
<table>
    <thead>
    <tr>
        <th>ID</th>
        <th>姓名</th>
        <th>年龄</th>
        <th>性别</th>
        <th>操作</th>
    </tr>
    </thead>
    <tbody>
    <tr th:each="student : ${students}">
        <td th:text="${student.id}"></td>
        <td th:text="${student.name}"></td>
        <td th:text="${student.age}"></td>
        <td th:text="${student.sex}"></td>
        <td>
            <a th:href="@{/students/edit/{id}(id=${student.id})}">编辑</a> |
            <a th:href="@{/students/delete/{id}(id=${student.id})}">删除</a>
        </td>
    </tr>
    </tbody>
</table>
<a href="/students/add">添加学生</a>
</body>
</html>

add.html

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
    <title>添加学生</title>
</head>
<body>
<h1>添加学生</h1>
<form action="#" th:action="@{/students/add}" th:object="${student}" method="post">
    <label>姓名:</label>
    <input type="text" th:field="*{name}"/><br/>
    <label>年龄:</label>
    <input type="number" th:field="*{age}"/><br/>
    <label>性别:</label>
    <input type="number" th:field="*{sex}"/><br/>
    <button type="submit">提交</button>
</form>
<a href="/students/">返回</a>
</body>
</html>

edit.html

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
    <title>编辑学生</title>
</head>
<body>
<h1>编辑学生</h1>
<form action="#" th:action="@{/students/edit/{id}(id=${student.id})}" th:object="${student}" method="post">
    <label>姓名:</label>
    <input type="text" th:field="*{name}"/><br/>
    <label>年龄:</label>
    <input type="number" th:field="*{age}"/><br/>
    <label>性别:</label>
    <input type="number" th:field="*{sex}"/><br/>
    <button type="submit">提交</button>
</form>
<a href="/students/">返回</a>
</body>
</html>

测试启动 Spring Boot 应用，访问：