spring boot DAO之Mybatis

Posted 2020-11-13

依赖

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>

        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.2</version>
        </dependency>

application-database.properties

#初始化数据库的时候，如果错误，是否继续启动。
spring.datasource.continue-on-error=false
#jdbc driver.默认通过uri来自动检测。
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
#jdbc url.连接数据库的uri
spring.datasource.url=jdbc:mysql://172.28.1.227:3310/fc?useUnicode=true&autoReconnect=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useServerPrepStmts=false
#数据库连接用户名
spring.datasource.username=fcdev
#数据连接密码
spring.datasource.password=123456
#全限定名，连接池。默认自动检测classpath
spring.datasource.type=com.zaxxer.hikari.HikariDataSource
#sql脚本字符
spring.datasource.sql-script-encoding=UTF-8

#mybatis配置
mybatis.check-config-location=false
mybatis.configuration.default-fetch-size=1000
mybatis.configuration.map-underscore-to-camel-case=true
#mybatis.mapper-locations=

源码-MybatisProperties

@ConfigurationProperties(prefix = MybatisProperties.MYBATIS_PREFIX)
public class MybatisProperties {

  public static final String MYBATIS_PREFIX = "mybatis";

  /**
   * Location of MyBatis xml config file.
   */
  private String configLocation;

  /**
   * Locations of MyBatis mapper files.
   */
  private String[] mapperLocations;

  /**
   * Packages to search type aliases. (Package delimiters are ",; 	
")
   */
  private String typeAliasesPackage;

  /**
   * Packages to search for type handlers. (Package delimiters are ",; 	
")
   */
  private String typeHandlersPackage;

  /**
   * Indicates whether perform presence check of the MyBatis xml config file.
   */
  private boolean checkConfigLocation = false;

  /**
   * Execution mode for {@link org.mybatis.spring.SqlSessionTemplate}.
   */
  private ExecutorType executorType;

  /**
   * Externalized properties for MyBatis configuration.
   */
  private Properties configurationProperties;

  /**
   * A Configuration object for customize default settings. If {@link #configLocation}
   * is specified, this property is not used.
   */
  @NestedConfigurationProperty
  private Configuration configuration;

}

源码-MybatisAutoConfiguration

@org.springframework.context.annotation.Configuration
@ConditionalOnClass({ SqlSessionFactory.class, SqlSessionFactoryBean.class })
@ConditionalOnBean(DataSource.class)
@EnableConfigurationProperties(MybatisProperties.class)
@AutoConfigureAfter(DataSourceAutoConfiguration.class)
public class MybatisAutoConfiguration {

  private static final Logger logger = LoggerFactory.getLogger(MybatisAutoConfiguration.class);

  private final MybatisProperties properties;

  private final Interceptor[] interceptors;

  private final ResourceLoader resourceLoader;

  private final DatabaseIdProvider databaseIdProvider;

  private final List<ConfigurationCustomizer> configurationCustomizers;

  public MybatisAutoConfiguration(MybatisProperties properties,
                                  ObjectProvider<Interceptor[]> interceptorsProvider,
                                  ResourceLoader resourceLoader,
                                  ObjectProvider<DatabaseIdProvider> databaseIdProvider,
                                  ObjectProvider<List<ConfigurationCustomizer>> configurationCustomizersProvider) {
    this.properties = properties;
    this.interceptors = interceptorsProvider.getIfAvailable();
    this.resourceLoader = resourceLoader;
    this.databaseIdProvider = databaseIdProvider.getIfAvailable();
    this.configurationCustomizers = configurationCustomizersProvider.getIfAvailable();
  }

  @PostConstruct
  public void checkConfigFileExists() {
    if (this.properties.isCheckConfigLocation() && StringUtils.hasText(this.properties.getConfigLocation())) {
      Resource resource = this.resourceLoader.getResource(this.properties.getConfigLocation());
      Assert.state(resource.exists(), "Cannot find config location: " + resource
          + " (please add config file or check your Mybatis configuration)");
    }
  }

  @Bean
  @ConditionalOnMissingBean
  public SqlSessionFactory sqlSessionFactory(DataSource dataSource) throws Exception {
    SqlSessionFactoryBean factory = new SqlSessionFactoryBean();
    factory.setDataSource(dataSource);
    factory.setVfs(SpringBootVFS.class);
    if (StringUtils.hasText(this.properties.getConfigLocation())) {
      factory.setConfigLocation(this.resourceLoader.getResource(this.properties.getConfigLocation()));
    }
    Configuration configuration = this.properties.getConfiguration();
    if (configuration == null && !StringUtils.hasText(this.properties.getConfigLocation())) {
      configuration = new Configuration();
    }
    if (configuration != null && !CollectionUtils.isEmpty(this.configurationCustomizers)) {
      for (ConfigurationCustomizer customizer : this.configurationCustomizers) {
        customizer.customize(configuration);
      }
    }
    factory.setConfiguration(configuration);
    if (this.properties.getConfigurationProperties() != null) {
      factory.setConfigurationProperties(this.properties.getConfigurationProperties());
    }
    if (!ObjectUtils.isEmpty(this.interceptors)) {
      factory.setPlugins(this.interceptors);
    }
    if (this.databaseIdProvider != null) {
      factory.setDatabaseIdProvider(this.databaseIdProvider);
    }
    if (StringUtils.hasLength(this.properties.getTypeAliasesPackage())) {
      factory.setTypeAliasesPackage(this.properties.getTypeAliasesPackage());
    }
    if (StringUtils.hasLength(this.properties.getTypeHandlersPackage())) {
      factory.setTypeHandlersPackage(this.properties.getTypeHandlersPackage());
    }
    if (!ObjectUtils.isEmpty(this.properties.resolveMapperLocations())) {
      factory.setMapperLocations(this.properties.resolveMapperLocations());
    }

    return factory.getObject();
  }

  @Bean
  @ConditionalOnMissingBean
  public SqlSessionTemplate sqlSessionTemplate(SqlSessionFactory sqlSessionFactory) {
    ExecutorType executorType = this.properties.getExecutorType();
    if (executorType != null) {
      return new SqlSessionTemplate(sqlSessionFactory, executorType);
    } else {
      return new SqlSessionTemplate(sqlSessionFactory);
    }
  }

  /**
   * This will just scan the same base package as Spring Boot does. If you want
   * more power, you can explicitly use
   * {@link org.mybatis.spring.annotation.MapperScan} but this will get typed
   * mappers working correctly, out-of-the-box, similar to using Spring Data JPA
   * repositories.
   */
  public static class AutoConfiguredMapperScannerRegistrar
      implements BeanFactoryAware, ImportBeanDefinitionRegistrar, ResourceLoaderAware {

    private BeanFactory beanFactory;

    private ResourceLoader resourceLoader;

    @Override
    public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {

      logger.debug("Searching for mappers annotated with @Mapper");

      ClassPathMapperScanner scanner = new ClassPathMapperScanner(registry);

      try {
        if (this.resourceLoader != null) {
          scanner.setResourceLoader(this.resourceLoader);
        }

        List<String> packages = AutoConfigurationPackages.get(this.beanFactory);
        if (logger.isDebugEnabled()) {
          for (String pkg : packages) {
            logger.debug("Using auto-configuration base package ‘{}‘", pkg);
          }
        }

        scanner.setAnnotationClass(Mapper.class);
        scanner.registerFilters();
        scanner.doScan(StringUtils.toStringArray(packages));
      } catch (IllegalStateException ex) {
        logger.debug("Could not determine auto-configuration package, automatic mapper scanning disabled.", ex);
      }
    }

    @Override
    public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
      this.beanFactory = beanFactory;
    }

    @Override
    public void setResourceLoader(ResourceLoader resourceLoader) {
      this.resourceLoader = resourceLoader;
    }
  }

  /**
   * {@link org.mybatis.spring.annotation.MapperScan} ultimately ends up
   * creating instances of {@link MapperFactoryBean}. If
   * {@link org.mybatis.spring.annotation.MapperScan} is used then this
   * auto-configuration is not needed. If it is _not_ used, however, then this
   * will bring in a bean registrar and automatically register components based
   * on the same component-scanning path as Spring Boot itself.
   */
  @org.springframework.context.annotation.Configuration
  @Import({ AutoConfiguredMapperScannerRegistrar.class })
  @ConditionalOnMissingBean(MapperFactoryBean.class)
  public static class MapperScannerRegistrarNotFoundConfiguration {

    @PostConstruct
    public void afterPropertiesSet() {
      logger.debug("No {} found.", MapperFactoryBean.class.getName());
    }
  }

}

TestMybatisDao

@Repository
@Mapper
public interface TestMybatisDao {

    @Select("select id, name from t_sys_menu where id = #{id}")
    SysMenu getById(@Param("id") int id);
}

springboot启动类

@MapperScan(basePackages="com.example.spring.dao")
@SpringBootApplication
public class DataDemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(DataDemoApplication.class, args);
    }
}

AppContextTest

@RunWith(SpringRunner.class)
@SpringBootTest
public class AppContextTest {
    @Autowired
    private TestMybatisDao testMybatisDao;

    @Test
    public void mybatisTest(){
        SysMenu sysMenu = testMybatisDao.getById(1);
        System.out.println("menuName = " + sysMenu.getName());
    }
}

注：mybatis-spring-boot-starter既可以使用xml配置也可以使用注解。

mybatis自定义配置：http://blog.51cto.com/881206524/2122449