我一直在尝试创建一个使用MyBatis作为数据访问层的Spring项目,作为我团队的概念验证。我真的希望尽可能避免使用XML配置,所以我尝试使用带注释的 @Configuration 类将所有内容连接在一起。
所有似乎正确连接,但我的映射器bean没有自动连接到我的服务层。
在我的示例中,我正在尝试将UserDao,User实体和UserService连接在一起。
public interface UserDao {
@Select("SELECT * FROM users WHERE id = #{userId}")
User get(@Param("userId") Integer userId);
}
@Component("User")
public class User implements Entity {
public Integer userId;
public String username;
/** ... getters/setters ommitted **/
}
@Service("UserService")
public class UserServiceImpl {
private UserDao userDao = null;
public User getUserDetails(Integer userId) {
return userDao.get(userId);
}
@Autowired
public void setUserDao(UserDao userDao) {
this.userDao = userDao;
}
}
我使用两个配置类将它们连接在一起。
@Configuration
@EnableLoadTimeWeaving(aspectjWeaving=AspectJWeaving.ENABLED)
@Import(DefaultDataAccessConfig.class) // I'm importing this because I thought ordering might be important, otherwise I was hoping to just let the component scanning pull in additional configuration files
@ComponentScan(basePackages="com.example.gwtspringpoc.server",
excludeFilters=@Filter(type=FilterType.ANNOTATION,
value=Controller.class))
public class ApplicationContextConfig {
/** No bean definitions needed here **/
}
@Configuration
@EnableTransactionManagement
public class DefaultDataAccessConfig implements TransactionManagementConfigurer {
@Bean
public DataSource dataSource() {
OracleDataSource ods = null;
try {
ods = new OracleDataSource();
} catch (SQLException e) {
throw new RuntimeException(e);
}
ods.setURL("jdbc:oracle:thin:@//localhost:9601/sid");
ods.setUser("user");
ods.setPassword("pass");
return ods;
}
@Override
@Bean(name="transactionManager")
public PlatformTransactionManager annotationDrivenTransactionManager() {
return new DataSourceTransactionManager(dataSource());
}
@Bean
public SqlSessionFactory sqlSessionFactory() {
SqlSessionFactoryBean sf = new SqlSessionFactoryBean();
sf.setDataSource(dataSource());
try {
return (SqlSessionFactory) sf.getObject();
} catch (Exception e) {
throw new RuntimeException(e);
}
}
@Bean
public SqlSession sqlSessionTemplate() {
return new SqlSessionTemplate(sqlSessionFactory());
}
/*
* This did not work at all. It seems to be configured correctly, but the UserDao bean never
* got created at any stage, which was very disappointing as I was hoping not to have to
* create a bean definition for each DAO manually
*/
/*@Bean
public static MapperScannerConfigurer mapperScannerConfig() {
MapperScannerConfigurer msc = new MapperScannerConfigurer();
msc.setBasePackage("com.ca.spna.gwtspringpoc.server.model.dao");
msc.setAnnotationClass(Repository.class);
return msc;
}*/
/*
* Because the above code did not work, I decided to create the mapping manually.
* This is most likely my problem - something about this setup. My understanding
* is that the MapperFactoryBean once instantiated by Spring, will create a proxy
* object of type UserDao with the name "userDao" that can be injected elsewhere.
*/
@Bean
public MapperFactoryBean<UserDao> userDao() {
MapperFactoryBean<UserDao> mfb = new MapperFactoryBean<UserDao>();
mfb.setMapperInterface(UserDao.class);
return mfb;
}
}
您可以阅读上面代码段中最后两种方法的注释,以深入了解我如何创建UserDao bean。
完成所有配置后,我创建了一个单元测试,尝试使用 AnnotationConfigContextLoader 测试 UserService ,但在尝试时会立即遇到以下异常运行测试:
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire method: public void com.example.gwtspringpoc.server.service.UserServiceImpl.setUserDao(com.example.gwtspringpoc.server.model.dao.UserDao); nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No matching bean of type [com.example.gwtspringpoc.server.model.dao.UserDao] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {}
看到之后,我在 UserService 中注释掉 @Autowired 并返回我的单元测试并注入了 ApplicationContext ,所以我可以检查它,名为“userDao”的bean实际上是 MapperProxy 实例。
那么,我是否理解 MapperFactoryBean 的工作方式是偏离轨道还是与注释驱动配置不兼容?另外,如果有人知道如何使 MapperScannerConfigurer 正常工作,我将非常感激!
答案 0 :(得分:14)
经过一段时间后,我能够解决问题,所以我会回答我自己的问题,以防其他人碰到类似的东西,因为那里没有很多可用的信息并且需要进行一些搜索。
问题归结为 MapperScannerConfigurer 是 BeanDefinitionRegistryPostProcessor 。事实证明,这与处理 @Configuration 文件并注册 @Beans 带注释的方法的机制相同。不幸的是,根据Spring Jira的这张票,一个 BeanDefinitionRegistryPostProcessor 无法使用另一个:https://jira.springsource.org/browse/SPR-7868
这里的建议是为处理器创建XML配置,然后在基于Java的配置中包含 @ImportResource 注释以将其拉入。那么,该建议并不完全准确。如果仍计划通过 AnnotationConfigContextLoader 引导配置,则不能简单地使用配置创建XML文件并将其拉入基于Java的配置。相反,您必须首先通过XML恢复加载配置,然后以“旧式”方式为配置文件创建bean。对我而言,这非常简单。
新申请背景
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.1.xsd http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-3.1.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.1.xsd">
<!--
Because MapperScannerConfigurer is a BeanDefinitionRegistryPostProcessor, it cannot be
configured via @Configuration files with a @Bean annotaiton, because those files are
themselves configured via a BeanDefinitionRegistryPostProcessor which cannot spawn
another one.
-->
<bean id="myBatisMapperScanner" class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<property name="basePackage" value="com.example.gwtspringpoc.server.model.dao"/>
<property name="annotationClass" value="org.springframework.stereotype.Repository"/>
</bean>
<!--
Load the rest of our configuration via our base configuration class
-->
<bean class="com.example.gwtspringpoc.server.spring.config.ApplicationContextConfig" />
</beans>
然后,我通过提供 ContextConfigLocation 来以传统方式引导上下文容器。这对我有用,因为我在上面的XML中引用的 ApplicationContextConfig 处理其他所有内容 - 包括组件扫描,它将拾取我所有其他 @Configuration 文件。
一旦我这样做,我的所有问题就消失了。我能像我预期的那样 @Autowire UserDao,一切都很精彩。
注意:强>
当我尝试通过创建 MapperFactoryBean 来手动定义UserDao时,就像在我原来的问题的代码示例中一样,创建了一个UserDao bean,但它的类型为 MapperProxy ,并且不是 @Autowire 。但是,我可以使用 @Repository(“userDao”)按名称加载它,这是值得的。我相信 MapperFactoryBean 会遇到与 MapperScannerConfigurer 类似的问题,并且与 @Configuration 文件完全不兼容,唉。
答案 1 :(得分:5)
来自mybatis.3.2.0和mybatis-spring.1.2.0, 而不是MapperFactoryBean,你可以使用MapperScan。
@Configuration
@MapperScan("org.mybatis.spring.sample.mapper")
public class AppConfig
{
@Bean
public DataSource dataSource()
{
return new EmbeddedDatabaseBuilder().addScript("schema.sql").build();
}
@Bean
public DataSourceTransactionManager transactionManager()
{
return new DataSourceTransactionManager(dataSource());
}
@Bean
public SqlSessionFactory sqlSessionFactory() throws Exception
{
SqlSessionFactoryBean sessionFactory = new SqlSessionFactoryBean();
sessionFactory.setDataSource(dataSource());
return sessionFactory.getObject();
}
}
答案 2 :(得分:2)
另一种可能的解决方案可以在Jason提到的jira中找到。解决了我的问题,我不必使用XML配置,我试图不惜一切代价避免......
https://jira.spring.io/browse/SPR-7868
@Configuration
public class A implements BeanDefinitionRegistryPostProcessor, PriorityOrdered {
@Override
public void postProcessBeanDefinitionRegistry(...) {
...
}
@Override
public void postProcessBeanFactory(...) {
...
}
@Override
public int getOrder() {
return 0;
}
}
答案 3 :(得分:-1)
您必须有一个上下文:弹簧配置中的组件扫描,以启用@Component的自动检测。查看reference。