SpringBoot+Mybatis使用Mapper接口注冊的幾種方式

更新時間：2021年07月13日 10:24:31 作者：一灰灰

本篇博文中主要介紹是Mapper接口與對應(yīng)的xml文件如何關(guān)聯(lián)的幾種姿勢，對大家的學(xué)習(xí)或者工作具有一定的參考學(xué)習(xí)價值，需要的朋友們下面隨著小編來一起學(xué)習(xí)學(xué)習(xí)吧

I. 環(huán)境準(zhǔn)備

1. 數(shù)據(jù)庫準(zhǔn)備

使用mysql作為本文的實例數(shù)據(jù)庫，新增一張表

CREATE TABLE `money` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(20) NOT NULL DEFAULT '' COMMENT '用戶名',
  `money` int(26) NOT NULL DEFAULT '0' COMMENT '錢',
  `is_deleted` tinyint(1) NOT NULL DEFAULT '0',
  `create_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '創(chuàng)建時間',
  `update_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT '更新時間',
  PRIMARY KEY (`id`),
  KEY `name` (`name`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8mb4;

2. 項目環(huán)境

本文借助 SpringBoot 2.2.1.RELEASE + maven 3.5.3 + IDEA進(jìn)行開發(fā)

pom依賴如下

<dependencies>
    <dependency>
        <groupId>org.mybatis.spring.boot</groupId>
        <artifactId>mybatis-spring-boot-starter</artifactId>
        <version>2.2.0</version>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
    </dependency>
</dependencies>

db配置信息 application.yml

spring:
  datasource:
    url: jdbc:mysql://127.0.0.1:3306/story?useUnicode=true&characterEncoding=UTF-8&useSSL=false&serverTimezone=Asia/Shanghai
    username: root
    password:

II. 實例演示

前面基礎(chǔ)環(huán)境搭建完成，接下來準(zhǔn)備下Mybatis的Entity,Mapper等基礎(chǔ)類

1. 實體類,Mapper類

數(shù)據(jù)庫實體類MoneyPo

@Data
public class MoneyPo {
    private Integer id;

    private String name;

    private Long money;

    private Integer isDeleted;

    private Timestamp createAt;

    private Timestamp updateAt;
}

對應(yīng)的Mapper接口（這里直接使用注解的方式來實現(xiàn)CURD）

public interface MoneyMapper {

    /**
     * 保存數(shù)據(jù)，并保存主鍵id
     *
     * @param po
     * @return int
     */
    @Options(useGeneratedKeys = true, keyProperty = "po.id", keyColumn = "id")
    @Insert("insert into money (name, money, is_deleted) values (#{po.name}, #{po.money}, #{po.isDeleted})")
    int save(@Param("po") MoneyPo po);

    /**
     * 更新
     *
     * @param id    id
     * @param money 錢
     * @return int
     */
    @Update("update money set `money`=#{money} where id = #{id}")
    int update(@Param("id") int id, @Param("money") long money);

    /**
     * 刪除數(shù)據(jù)
     *
     * @param id id
     * @return int
     */
    @Delete("delete from money where id = #{id}")
    int delete(@Param("id") int id);

    /**
     * 主鍵查詢
     *
     * @param id id
     * @return {@link MoneyPo}
     */
    @Select("select * from money where id = #{id}")
    @Results(id = "moneyResultMap", value = {
            @Result(property = "id", column = "id", id = true, jdbcType = JdbcType.INTEGER),
            @Result(property = "name", column = "name", jdbcType = JdbcType.VARCHAR),
            @Result(property = "money", column = "money", jdbcType = JdbcType.INTEGER),
            @Result(property = "isDeleted", column = "is_deleted", jdbcType = JdbcType.TINYINT),
            @Result(property = "createAt", column = "create_at", jdbcType = JdbcType.TIMESTAMP),
            @Result(property = "updateAt", column = "update_at", jdbcType = JdbcType.TIMESTAMP)})
    MoneyPo getById(@Param("id") int id);
}

對應(yīng)的Service類

@Slf4j
@Service
public class MoneyService {
    @Autowired
    private MoneyMapper moneyMapper;

    public void basicTest() {
        int id = save();
        log.info("save {}", getById(id));
        boolean update = update(id, 202L);
        log.info("update {}, {}", update, getById(id));
        boolean delete = delete(id);
        log.info("delete {}, {}", delete, getById(id));
    }

    private int save() {
        MoneyPo po = new MoneyPo();
        po.setName("一灰灰blog");
        po.setMoney(101L);
        po.setIsDeleted(0);
        moneyMapper.save(po);
        return po.getId();
    }

    private boolean update(int id, long newMoney) {
        int ans = moneyMapper.update(id, newMoney);
        return ans > 0;
    }

    private boolean delete(int id) {
        return moneyMapper.delete(id) > 0;
    }

    private MoneyPo getById(int id) {
        return moneyMapper.getById(id);
    }
}

2. 注冊方式

注意，上面寫完之后，若不通過下面的幾種方式注冊Mapper接口，項目啟動會失敗，提示找不到MoneyMapper對應(yīng)的bean

Field moneyMapper in com.git.hui.boot.mybatis.service.MoneyService required a bean of type 'com.git.hui.boot.mybatis.mapper.MoneyMapper' that could not be found.

2.1 @MapperScan注冊方式

在配置類or啟動類上，添加@MapperScan注解來指定Mapper接口的包路徑，從而實現(xiàn)Mapper接口的注冊

@MapperScan(basePackages = "com.git.hui.boot.mybatis.mapper")
@SpringBootApplication
public class Application {

    public Application(MoneyService moneyService) {
        moneyService.basicTest();
    }

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

執(zhí)行之后輸出結(jié)果如下

2021-07-06 19:12:57.984 INFO 1876 --- [           main] c.g.h.boot.mybatis.service.MoneyService : save MoneyPo(id=557, name=一灰灰blog, money=101, isDeleted=0, createAt=2021-07-06 19:12:57.0, updateAt=2021-07-06 19:12:57.0)
2021-07-06 19:12:58.011 INFO 1876 --- [           main] c.g.h.boot.mybatis.service.MoneyService : update true, MoneyPo(id=557, name=一灰灰blog, money=202, isDeleted=0, createAt=2021-07-06 19:12:57.0, updateAt=2021-07-06 19:12:57.0)
2021-07-06 19:12:58.039 INFO 1876 --- [           main] c.g.h.boot.mybatis.service.MoneyService : delete true, null

注意：

basePackages: 傳入Mapper的包路徑，數(shù)組，可以傳入多個
包路徑支持正則，如com.git.hui.boot.*.mapper
- 上面這種方式，可以避免讓我們所有的mapper都放在一個包路徑下，從而導(dǎo)致閱讀不友好

2.2 @Mapper 注冊方式

前面的@MapperScan指定mapper的包路徑，這個注解則直接放在Mapper接口上

@Mapper
public interface MoneyMapper {
...
}

測試輸出省略...

2.3 MapperScannerConfigurer注冊方式

使用MapperScannerConfigurer來實現(xiàn)mapper接口注冊，在很久以前，還是使用Spring的xml進(jìn)行bean的聲明的時候，mybatis的mapper就是這么玩的

<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="xxx"/>
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
</bean>

對應(yīng)的java代碼如下：

@Configuration
public class AutoConfig {
    @Bean(name = "sqlSessionFactory")
    public SqlSessionFactory sqlSessionFactory(DataSource dataSource) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        bean.setMapperLocations(
                // 設(shè)置mybatis的xml所在位置，這里使用mybatis注解方式，沒有配置xml文件
                new PathMatchingResourcePatternResolver().getResources("classpath*:mapping/*.xml"));
        return bean.getObject();
    }

    @Bean("sqlSessionTemplate")
    public SqlSessionTemplate sqlSessionTemplate(SqlSessionFactory storySqlSessionFactory) {
        return new SqlSessionTemplate(storySqlSessionFactory);
    }

    @Bean
    public MapperScannerConfigurer mapperScannerConfigurer() {
        MapperScannerConfigurer mapperScannerConfigurer = new MapperScannerConfigurer();
        mapperScannerConfigurer.setBasePackage("com.git.hui.boot.mybatis.mapper");
        mapperScannerConfigurer.setSqlSessionFactoryBeanName("sqlSessionFactory");
        mapperScannerConfigurer.setSqlSessionTemplateBeanName("sqlSessionTemplate");
        return mapperScannerConfigurer;
    }
}

測試輸出省略