本文讲述Spring Boot如何通过mybatis-spring-boot-starter集成Mybatis,并且在Mapper中如何映射Model属性和表的字段。


下面给出一个简单的示例。

pom.xml

首先要引入mybatis的依赖

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<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>1.1.1</version>
</dependency>

table_user

数据库建表

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CREATE TABLE IF NOT EXISTS `tb_user`(
`id` INT(11) NOT NULL,
`name` VARCHAR(100) NOT NULL,
`created_by` VARCHAR(100) NOT NULL,
PRIMARY KEY ( `id` )
)ENGINE=InnoDB DEFAULT CHARSET=utf8;

User

实体类

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public class User {

private Integer id;
private String name;
private String createdBy;
//省略了setters & getters

}

UserMapper

Mapper接口中可以通过注解的形式直接写sql,比将sql分离到xml中的方式更方便

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@Mapper
public interface UserMapper {

@Select("select * from tb_user where id = #{id}")
User selectById(@Param("id") int id);

@Select("select * from tb_user")
List<User> selectAll();

@Insert("insert into tb_user(id, name, created_by) values(#{id}, #{name}, #{createdBy})")
@Results(id = "user",
value = {
@Result(column = "id",property = "id"),
@Result(column = "name",property = "name"),
@Result(column = "created_by",property = "createdBy")
}
)
//@Options(useGeneratedKeys = true, keyProperty = "id", keyColumn = "id")
void insertUser(User user);

@Update("update tb_user set id = #{id}, name = #{name}, created_by = #{createdBy}")
@ResultMap(value = "user")
void updateUser(User user);

@Delete("delete from tb_user where id = #{id}")
void deleteById(@Param("id") int id);

}

  • @Select, @Insert, @Update, @Delete显然就是sql语句的注解了.
  • @Param是根据别名取参数的.
  • @Results和@Result配合使用, 就可以将实体类属性和表字段进行一一映射.
    • @Results的参数id表示这个映射的别名, 可以配合@ResultMap使用.
    • @Result的参数column表示表字段名, property表示实体属性名.
  • @Options可以在插入时返回主键值, 在这里没什么用. 一般用于在主键id自增的情况下, 插入操作不定义id, 可以在插入数据库表后返回该条插入信息的主键id.

UserService

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@Service
public class ScriptService {

@Autowired
private UserMapper userMapper;

public User selectById(int id) {
User user = userMapper.selectById(id);
return user;
}

public List<User> selectAll() {
List<User> list = userMapper.selectAll();
return list;
}

public int insertUser(User user) {
userMapper.insertUser(user);
retyrn user.getId();
}

public boolean updateUser(User user) {
int id = user.getId();
user check = userMapper.selectById(id);
if (check == null) {
return false;
}
userMapper.updateUser(user);
return true;
}

public boolean deleteById(int id) {
user check = userMapper.selectById(id);
if (check == null) {
return false;
}
userMapper.deleteById(id);
return true;
}

}

UserController

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@Controller
@RequestMapping("/user")
public class UserController {

@Autowired
private UserService userService;

@RequestMapping(value = "/selectById/{id}", method = RequestMethod.GET)
@ResponseBody
public User selectById(@PathVariable("id") int id) {
return userService.selectById(id);
}

@RequestMapping(value = "/selectAll", method = RequestMethod.GET)
@ResponseBody
public List<User> selectAll() {
return userService.selectAll();
}

@RequestMapping(value = "/insertUser", method = RequestMethod.POST)
@ResponseBody
public int insertUser(@RequestBody User user) {
return userService.insertUser(user);
}

@RequestMapping(value = "/updateUser", method = RequestMethod.POST)
@ResponseBody
public boolean updateUser(@RequestBody User user) {
return userService.updateUser(user);
}

@RequestMapping(value = "/deleteById/{id}", method = RequestMethod.POST)
@ResponseBody
public boolean deleteById(@PathVariable("id") int id) {
return userService.deleteById(id);
}

}



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