SpringBoot——MyBatis整合数据库连接、配置文件方式、注解方式、配置文件+注解方式_mybatis怎么整合数据库

1.pom.xml

        <!-- 连接数据库 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <!-- web开发 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!-- mybatis整合,包含jdbc包 -->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.2.2</version>
        </dependency>
        <!-- 热部署 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <!-- 配置文件提示 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-configuration-processor</artifactId>
            <optional>true</optional>
        </dependency>
        <!-- 日志、getset方法等 -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <!-- 测试 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!-- druid数据源 -->
<!--        <dependency>-->
<!--            <groupId>com.alibaba</groupId>-->
<!--            <artifactId>druid</artifactId>-->
<!--            <version>1.0.18</version>-->
<!--        </dependency>-->
        <!--   官方的数据域，监控中心、druid数据域     -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.17</version>
        </dependency>
        <!--  引入静态模板引擎，才能访问templates下面的静态页面  -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>

2.bean

@Data
public class GasTest {
    String isLeak;
    int id;
    String time;
    float pressure;
    //需要开启驼峰命名规则
    float flowRate;
    float velocity;
}

@Data：lombok的jar包，封装get、set方法

3.resources目录截图

建议先学SpringBoot的静态资源和动态资源目录

4.application.yml

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/graduationproject
    username: root
    password: 113846
    driver-class-name: com.mysql.jdbc.Driver            #5.x版本mysql
 
#配置mybatis规则
mybatis:
#  config-location: classpath:mybatis/mybatis-config.xml    #全局只允许一个配置文件，这是开启驼峰命名规则的配置文件
  mapper-locations: classpath:mybatis/mapper/*.xml
  configuration:   #指定mybatis全局配置文件中的配置项目，那就不需要mybatis-config.xml了
    map-underscore-to-camel-case: true          #开启驼峰命名规则

5.整合mybatis

5.1使用配置文件方式整合mybatis，查询数据库

(1).mapper

@Mapper
public interface GasTestMapper {
    public GasTest getIdInfo(int id);
}

@Mapper：声明这是一个bean。在连接数据库中加上@Mapper注解，使用mybatis配置文件mapper.xml，mapper.xml中的namespace指向mapper，会动态生成bean。在服务实现层serviceImpl中能够@Autowired注解动态注入该bean。

(2).mybatis\mapper\GasTestMapper.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.mapper.GasTestMapper">
    <select id="getIdInfo" resultType="com.example.bean.GasTest">
        select * from gastest where id=#{id}
    </select>
</mapper>

namespace：命名空间，mapper接口类的路径

id：mapper中的接口方法

resultType：返回数据集的数据类型

(3).service和serviceimpl

@Service
public interface GasTestService {
    public GasTest getIdInfo(int id);
}
 
 
@Service
public class GasTestServiceImpl implements GasTestService {
    @Autowired
    GasTestMapper gasTestMapper;
    @Override
    public GasTest getIdInfo(int id) {
        return gasTestMapper.getIdInfo(id);
    }
}

(4)controller

@Slf4j
@RestController
public class GasTestController {
    @Autowired
    GasTestService gasTestService;
 
    //使用配置文件方式整合mybatis，查询数据库，方式1
    //注解RequestParam，路径传参，参为id，方式1
    @RequestMapping("/gas")
    public GasTest getIdInfo(@RequestParam("id") int id){
        return gasTestService.getIdInfo(id);
    }
}

(5)接口测试结果展示

5.2使用纯注解方式整合mybatis，查询数据库

(1).mapper

@Mapper
public interface GasTest2Mapper {
    //方式2
    @Select("select * from gastest where id=#{id}")
    public GasTest2 getIdInfo(int id);
}

(2).service和serviceimpl

@Service
public interface GasTest2Service {
    public GasTest2 getIdInfo(int id);
}
 
@Service
public class GasTest2ServiceImpl implements GasTest2Service {
    @Autowired
    GasTest2Mapper gasTest2Mapper;
 
    public GasTest2 getIdInfo(int id){
        return gasTest2Mapper.getIdInfo(id);
    }
}

(3).controller

    @Autowired
    GasTest2Service gasTest2Service;
    //使用纯注解整合mybatis，查询数据库，方式2
    //注解RequestParam，路径传参，参为id，方式2
    @RequestMapping("/gas2")
    public GasTest2 getIdInfo2(@RequestParam("id") int id){
        return gasTest2Service.getIdInfo(id);
    }

(4).接口测试展示结果

5.3使用注解+配置文件方式整合mybatis，查询数据库

(1).mapper或mapper

@Mapper
public interface GasTest2Mapper {
    //方式3
    //也可以用配置文件方式mybatis\mapper\GasTest2Mapper.xml
    @Insert("insert into gastest(`isleak`,`time`,`pressure`,`flow_rate`,`velocity`) values(#{isLeak},#{time},#{pressure},#{flowRate},#{velocity})")
    //开启将没有表单传参的自增id返回,Options注解方式，
    @Options(useGeneratedKeys = true,keyProperty = "id")
    public void insert(GasTest2 gasTest2);
}    
 

(2).mybatis\mapper\GasTest2Mapper.xml或mybatis\mapper\GasTest2Mapper.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.mapper.GasTest2Mapper">
    <!--  useGeneratedKeys="true" keyProperty="id": 开启将没有表单传参的自增id返回  -->
<!--    <insert id="insert" useGeneratedKeys="true" keyProperty="id">-->
<!--        insert into gastest(`isleak`,`time`,`pressure`,`flow_rate`,`velocity`) values(#{isLeak},#{time},#{pressure},#{flowRate},#{velocity})-->
<!--    </insert>-->
</mapper>

(3).service和serviceImpl

@Service
public interface GasTest2Service {
    public void insert(GasTest2 gasTest2);
}
 
@Service
public class GasTest2ServiceImpl implements GasTest2Service {
    @Autowired
    GasTest2Mapper gasTest2Mapper;
 
    public void insert(GasTest2 gasTest2){
        gasTest2Mapper.insert(gasTest2);
    }
}

(4).controller

 
    //方式3
    //也可以用配置文件方式mybatis\mapper\GasTest2Mapper.xml
    @Insert("insert into gastest(`isleak`,`time`,`pressure`,`flow_rate`,`velocity`) values(#{isLeak},#{time},#{pressure},#{flowRate},#{velocity})")
    //post请求。insert这个方法既可以1.使用配置方式 2.也可以使用注解方式 3.或配置+注解方式一块用
    @PostMapping("/gas3")
    public GasTest2 insertGasTestInfo(GasTest2 gasTest2){
        log.info("gasTest2={}",gasTest2);
        gasTest2Service.insert(gasTest2);
        return gasTest2;
    }

(5).接口测试展示结果