IDEA2023 SpringBoot整合MyBatis（三）

一、数据库表

CREATE TABLE students (
    id INT AUTO_INCREMENT PRIMARY KEY,
    name VARCHAR(100) NOT NULL,
    age INT,
    gender ENUM('Male', 'Female', 'Other'),
    email VARCHAR(100) UNIQUE,
    phone_number VARCHAR(20),
    address VARCHAR(255),
    date_of_birth DATE,
    enrollment_date DATE,
    course VARCHAR(100)
);

-- 插入10条学生数据
INSERT INTO students (name, age, gender, email, phone_number, address, date_of_birth, enrollment_date, course) VALUES
('John Doe', 20, 'Male', 'john.doe@example.com', '1234567890', '123 Main St, City', '2003-01-01', '2023-09-01', 'Computer Science'),
('Jane Smith', 21, 'Female', 'jane.smith@example.com', '0987654321', '456 Elm Rd, Town', '2002-02-02', '2023-09-01', 'Business Administration'),
('Michael Johnson', 19, 'Male', 'michael.johnson@example.com', '1122334455', '789 Oak Ave, Village', '2004-03-03', '2023-09-01', 'Electrical Engineering'),
('Emily Davis', 22, 'Female', 'emily.davis@example.com', '5544332211', '321 Pine Blvd, County', '2001-04-04', '2023-09-01', 'Mechanical Engineering'),
('William Brown', 20, 'Male', 'william.brown@example.com', '9988776655', '654 Cedar Ln, District', '2003-05-05', '2023-09-01', 'Civil Engineering'),
('Olivia Wilson', 21, 'Female', 'olivia.wilson@example.com', '4433221100', '987 Walnut St, Borough', '2002-06-06', '2023-09-01', 'Chemistry'),
('Benjamin Taylor', 19, 'Male', 'benjamin.taylor@example.com', '7766554433', '246 Maple Dr, Neighborhood', '2004-07-07', '2023-09-01', 'Physics'),
('Grace Anderson', 22, 'Female', 'grace.anderson@example.com', '3322110099', '852 Birch Rd, Hamlet', '2001-08-08', '2023-09-01', 'Mathematics'),
('Henry Thompson', 20, 'Male', 'henry.thompson@example.com', '6655443322', '587 Aspen St, Province', '2003-09-09', '2023-09-01', 'Biology'),
('Chloe Robinson', 21, 'Female', 'chloe.robinson@example.com', '9977665544', '101 Poplar Ave, Region', '2002-10-10', '2023-09-01', 'Psychology');

二、在pom文件中添加MyBatis相关依赖包，Mysql驱动依赖

<dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
      
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
         <!-- mybatis依赖 -->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>3.0.3</version>
        </dependency>
         <!-- mysql依赖 -->
        <dependency>
            <groupId>com.mysql</groupId>
            <artifactId>mysql-connector-j</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!-- mybatis测试依赖 -->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter-test</artifactId>
            <version>3.0.3</version>
            <scope>test</scope>
        </dependency>

当我们没有热部署的时候，我们必须在代码修改完后再重启程序，程序才会同步你修改的信息。那么我们可以手动启动热部署-》》》

     <!-- 热部署工具 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional>
        </dependency>

三、编写实体类

public class Student {
    // 定义属性
    private String name; // 姓名
    private int age; // 年龄
    private String gender; // 性别
    private String email; // 邮箱
    private String phoneNumber; // 电话号码
    private String address; // 地址
    private java.util.Date dateOfBirth; // 出生日期
    private java.util.Date enrollmentDate; // 入学日期
    private String course; // 课程

   ...setXXX and getXXX and constructor and toString...

四、编写映射类StudentMapper

 */
@Mapper
public interface StudentMapper  {

   // @Select("select * from student where id = #{id}")
    public List<Student> findById(int id);

   //  @Select("select * from student")
    public List<Student> findAll();
}

注意：如果不写@Select注解，则就需要写Mapper映射文件

五、编写Mapper映射文件

mybatis – MyBatis 3 | 配置

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.hlx.springbootdemo1.mapper.StudentMapper">
    <select id="findById" parameterType="int" resultType="Student">
        SELECT * FROM student WHERE id = #{id}
    </select>

    <select id="findAll" resultType="Student">
      select * from student
    </select>

</mapper>

六、编写配置文件

#mysql数据源配置
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/school?useSSL=false&serverTimezone=UTC&allowPublicKeyRetrieval=true
spring.datasource.username=root
spring.datasource.password=123456

#mybatis
mybatis.mapper-locations=classpath*:mapper/*.xml

#实体类的别名
mybatis.type-aliases-package=com.hlx.springbootdemo1.entity

#日志
logging.pattern.console='%d{HH:mm:ss.SSS} %clr(%-5level) ---  [%-15thread] %cyan(%-50logger{50}):%msg%n'

七、编写业务类

@Service
public class StudentService {
    @Autowired
    private StudentMapper studentMapper;

    public List<Student> findAll(){
        return (studentMapper.findAll());
    }

    public Student findById(int id){
        return (studentMapper.findById(id));
    }
}

八、编写控制器类

@RestController
public class StudentsController {
    @Autowired
    private StudentService studentService;

    @GetMapping("/user/{id}")
    public Student findById(@PathVariable int id) {
        return studentService.findById(id);
    }

    @GetMapping("/user/all")
    public List<Student> findAll() {
        return studentService.findAll();
    }
}

九、启动类

@SpringBootApplication
@MapperScan("com.hlx.springbootdemo1.mapper")
public class SpringbootDemo1Application {

    public static void main(String[] args) {
        SpringApplication.run(SpringbootDemo1Application.class, args);
    }

}