使用springboot框架，mybatis,maven写一个一对多的crud事例

好的，我来给你写一个使用 springboot 框架、mybatis、maven 的一对多 CRUD 示例。

首先，需要在 pom.xml 中声明 springboot 和 mybatis 的依赖：

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
  <groupId>org.mybatis.spring.boot</groupId>
  <artifactId>mybatis-spring-boot-starter</artifactId>
  <version>2.1.3</version>
</dependency>

然后，可以定义两个实体类，一个是 Department，表示部门，另一个是 Employee，表示员工：

@Data
@AllArgsConstructor
@NoArgsConstructor
@Table(name = "department")
public class Department {
  @Id
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  private Long id;

  private String name;
}

@Data
@AllArgsConstructor
@NoArgsConstructor
@Table(name = "employee")
public class Employee {
  @Id
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  private Long id;

  private String name;

  @ManyToOne
  @JoinColumn(name = "department_id")
  private Department department;
}

接着，创建 DepartmentMapper 和 EmployeeMapper 接口：

public interface DepartmentMapper {
  @Insert("INSERT INTO department(name) VALUES(#{name})")
  @Options(useGeneratedKeys = true, keyProperty = "id")
  void insert(Department department);

  @Update("UPDATE department SET name = #{name} WHERE id = #{id}")
  void update(Department department);

  @Delete("DELETE FROM department WHERE id = #{id}")
  void delete(Long id);

  @Select("SELECT * FROM department WHERE id = #{id}")
  Department select(Long id);

  @Select("SELECT * FROM department")
  List<Department> selectAll();
}

public interface EmployeeMapper {
  @Insert("INSERT INTO employee(name, department_id) VALUES(#{name}, #{department.id})")
  @Options(useGeneratedKeys = true, keyProperty = "id")
  void insert(Employee employee);

  @Update("UPDATE employee SET name = #{name}, department_id = #{department.id} WHERE id = #{id}")
  void update(Employee employee);

  @Delete("DELETE FROM employee WHERE id = #{