用springboot集成mybatis写一个增删改查的案例

首先，你需要在pom.xml文件中添加相关依赖：

<dependencies>
    <!-- Spring Boot Starter -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter</artifactId>
    </dependency>
    <!-- Spring Boot MyBatis Starter -->
    <dependency>
        <groupId>org.mybatis.spring.boot</groupId>
        <artifactId>mybatis-spring-boot-starter</artifactId>
    </dependency>
    <!-- MySQL Connector -->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
    </dependency>
</dependencies>

接下来，创建一个实体类User.java：

public class User {
    private Long id;
    private String name;
    private Integer age;
    // ... 省略getter和setter方法
}

然后，创建一个Mapper接口UserMapper.java：

public interface UserMapper {
    List<User> findAll();
    User findById(Long id);
    void save(User user);
    void update(User user);
    void delete(Long id);
}

接着，创建一个Mapper XML文件UserMapper.xml：

<mapper namespace="com.example.mapper.UserMapper">
    <resultMap id="userResultMap" type="com.example.entity.User">
        <id property="id" column="id"/>
        <result property="name" column="name"/>
        <result property="age" column="age"/>
    </resultMap>

    <select id="findAll" resultMap="userResultMap">
        SELECT * FROM user
    </select>

    <select id="findById" parameterType="java.lang.Long" resultMap="userResultMap">
        SELECT * FROM user WHERE id = #{id}
    </select>

    <insert id="save" parameterType="com.example.entity.User">
        INSERT INTO user (name, age) VALUES (#{name}, #{age})
    </insert>

    <update id="update" parameterType="com.example.entity.User">
        UPDATE user SET name = #{name}, age = #{age} WHERE id = #{id}
    </update>

    <delete id="delete" parameterType="java.lang.Long">
        DELETE FROM user WHERE id = #{id}
    </delete>
</mapper>

然后，创建一个Service类UserServiceImpl.java：

@Service
public class UserServiceImpl implements UserService {

    @Autowired
    private UserMapper userMapper;

    @Override
    public List<User> findAll() {
        return userMapper.findAll();
    }

    @Override
    public User findById(Long id) {
        return userMapper.findById(id);
    }

    @Override
    public void save(User user) {
        userMapper.save(user);
    }

    @Override
    public void update(User user) {
        userMapper.update(user);
    }

    @Override
    public void delete(Long id) {
        userMapper.delete(id);
    }
}

最后，创建一个Controller类UserController.java：

@RestController
@RequestMapping("/users")
public class UserController {

    @Autowired
    private UserService userService;

    @GetMapping
    public List<User> findAll() {
        return userService.findAll();
    }

    @GetMapping("/{id}")
    public User findById(@PathVariable("id") Long id) {
        return userService.findById(id);
    }

    @PostMapping
    public void save(@RequestBody User user) {
        userService.save(user);
    }

    @PutMapping("/{id}")
    public void update(@PathVariable("id") Long id, @RequestBody User user) {
        user.setId(id);
        userService.update(user);
    }

    @DeleteMapping("/{id}")
    public void delete(@PathVariable("id") Long id) {
        userService.delete(id);
    }
}

现在，你可以启动Spring Boot应用，并访问以下API来测试增删改查功能：

• GET /users：获取所有用户
• GET /users/{id}：根据id获取用户
• POST /users：创建用户
• PUT /users/{id}：根据id更新用户
• DELETE /users/{id}：根据id删除用