[Java知识库]SpringBoot-MyBatis

环境搭建

# mysql数据库连接
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/book
spring.datasource.username=root
spring.datasource.password=12345

# 配置mybatis规则
mybatis:
  #  config-location: classpath:mybatis/mybatis-config.xml
  mapper-locations: classpath:mybatis/mapper/*.xml
  configuration:
    map-underscore-to-camel-case: true # 开启驼峰命名

#  可以不写全局；配置文件，所有全局配置文件的配置都放在configuration配置项中即可

配置

UserMapper.xml

<?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.example.demo.mapper.UserMapper">
    <!--    public Account getAcct(Long id); -->
    <select id="getUser" resultType="com.example.demo.bean.User">
        select * from  t_user where  id=#{id}
    </select>

    <select id="listUser" resultType="com.example.demo.bean.User">
        select * from  t_user
    </select>
</mapper>

UserService

@Service
public class UserService {

    @Autowired
    UserMapper userMapper;

    public User getUserById(int id){
        return userMapper.getUser(id);
    }
}

UserMapper

public interface UserMapper {

    public User getUser(int id);
    
    public List<User> listUser();

}

MybatisController

@RestController
public class MybatisController {

    @Autowired
    UserService userService;
    @GetMapping("/user")
    public User getById(@RequestParam("id") int id){
        return userService.getUserById(id);
    }
}

注解

BookMapper

public interface BookMapper {

    @Select("select * from  t_book where  id=#{id}")
    public Book getBookById(int book);
}