springboot快速整合mybatis

springboot整合mybatis

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環境：jdk1.8，idea，MySQL 8.0.16

1. 新建一個springboot項目

2. 添加pom依賴

添加相關依賴，就可以連接數據庫了

	 <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
            <version>2.2.6.RELEASE</version>
	 </dependency>
	 <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.1</version>
 	  </dependency>
 
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.16</version>
        </dependency>

3. 在application.yml中配置數據源和mybatis

spring:
  #數據源
  datasource:
    username: root
    password: 123
    url: jdbc:mysql://localhost:3306/ccc?useUnicode=true&characterEncoding=utf-8&useSSL=true&serverTimezone=UTC
    driver-class-name: com.mysql.cj.jdbc.Driver
    
#  就不用單獨寫一個mybatis-config.xml文件了，也可以單獨寫一個
mybatis:
#  mapper-locations: classpath:mapping/*.xml，mapper接口的實現都在這
# 實體類的別名
  type-aliases-package: com.example.demo.entity

  # spring boot集成mybatis的方式打印sql
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

實體類和mapper接口

用了lombok

@Data
@NoArgsConstructor
@AllArgsConstructor
public class Teacher {
    private int id;
    private String name;
    private int collection;
}

mapper接口

@Repository
public interface TeacherMapper {
    @Select("SELECT * FROM teachers")
    List<Teacher> selectAll();
    @Select("select * from teachers where name=#{name}")
    Teacher selectByName(String name);
    @Select("select * from teachers where id=#{id}")
    Teacher selectById(int id);
}

application啓動類中添加@MapperScan註解，掃描mapper接口，或者在每個mapper接口上添加@Mapper

@SpringBootApplication
@MapperScan("com.example.demo.mapper")
public class DemoApplication {

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

}

4. 項目結構

5. service層調用接口

可以直接用@Autowired自動注入teacherMapper，也可用構造函數

@Service
public class TeacherServiceImpl implements TeacherService {
    final TeacherMapper teacherMapper;

    public TeacherServiceImpl(TeacherMapper teacherMapper) {
        this.teacherMapper = teacherMapper;
    }

    @Override
    public List<Teacher> selectAll() {
        List<Teacher> list = teacherMapper.selectAll();
        return list;
    }
    @Override
    public Teacher selectByName(String name) {
        return teacherMapper.selectByName(name);
    }
    @Override
    public Teacher selectById(int id) {
        return teacherMapper.selectById(id);
    }
}

6. 最後直接調用service即可返回查詢結果