我使用Spring Boot和MongoDB创建带有注释的简单新闻系统。我想专注于代码质量。我使用泛型创建服务来保存类中的数据。
我的代码:
Dao.java
@Repository
public interface Dao<T, ID extends Serializable> extends MongoRepository<T, ID>{
}
DaoService.java
@Service
public class DaoService<T> extends AbstractService<T, Long> {
@Autowired
public DaoService(Dao<T, Long> dao) {
super(dao);
}
}
Service.java
@org.springframework.stereotype.Service
public interface Service<T, ID extends Serializable> {
T save(T entity);
}
AbstractService.java
public abstract class AbstractService<T, ID extends Serializable> implements
Service<T, ID> {
protected final Logger logger = LoggerFactory.getLogger(getClass());
protected Dao<T, ID> dao;
public AbstractService(Dao<T, ID> dao) {
this.dao = dao;
}
@Override
public T save(T entity) {
this.logger.debug("Create a new {} with information: {}", entity.getClass(),
entity.toString());
return this.dao.save(entity);
}
}
和2 repo
@Repository
public interface CommentDao extends Dao<Comment, Long> {
}
和
@Repository
public interface NewsDao extends Dao<News, Long> {
}
我的控制器:
@RestController
@RequestMapping("/news")
public class NewsController {
private final DaoService<News> newsService;
private final DaoService<Comment> commentDaoService;
public NewsController(DaoService<News> newsService, DaoService<Comment> commentDaoService) {
this.newsService = newsService;
this.commentDaoService = commentDaoService;
}
@RequestMapping(method = RequestMethod.GET)
public void save(){
newsService.save(new News("elo","a","c"));
commentDaoService.save(new Comment("iss","we"));
}
}
错误:
2016-03-02 23:22:30.265 WARN 6100 --- [ main] ationConfigEmbeddedWebApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'daoService' defined in file [C:\Users\Lukasz\IdeaProjects\NewsSystem_REST\build\classes\main\com\newssystem\lab\dao\DaoService.class]: Unsatisfied dependency expressed through constructor argument with index 0 of type [com.newssystem.lab.dao.Dao]: : No qualifying bean of type [com.newssystem.lab.dao.Dao] is defined: expected single matching bean but found 2: newsDao,commentDao; nested exception is org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type [com.newssystem.lab.dao.Dao] is defined: expected single matching bean but found 2: newsDao,commentDao
2016-03-02 23:22:30.273 INFO 6100 --- [ main] o.apache.catalina.core.StandardService : Stopping service Tomcat
2016-03-02 23:22:30.296 ERROR 6100 --- [ main] o.s.boot.SpringApplication : Application startup failed
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'daoService' defined in file [C:\Users\Lukasz\IdeaProjects\NewsSystem_REST\build\classes\main\com\newssystem\lab\dao\DaoService.class]: Unsatisfied dependency expressed through constructor argument with index 0 of type [com.newssystem.lab.dao.Dao]: : No qualifying bean of type [com.newssystem.lab.dao.Dao] is defined: expected single matching bean but found 2: newsDao,commentDao; nested exception is org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type [com.newssystem.lab.dao.Dao] is defined: expected single matching bean but found 2: newsDao,commentDao
at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:749) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:185) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1143) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1046) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:510) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:772) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:839) ~[spring-context-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:538) ~[spring-context-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:118) ~[spring-boot-1.3.2.RELEASE.jar:1.3.2.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:766) [spring-boot-1.3.2.RELEASE.jar:1.3.2.RELEASE]
at org.springframework.boot.SpringApplication.createAndRefreshContext(SpringApplication.java:361) [spring-boot-1.3.2.RELEASE.jar:1.3.2.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:307) [spring-boot-1.3.2.RELEASE.jar:1.3.2.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1191) [spring-boot-1.3.2.RELEASE.jar:1.3.2.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1180) [spring-boot-1.3.2.RELEASE.jar:1.3.2.RELEASE]
at com.newssystem.lab.NewsSystemApplication.main(NewsSystemApplication.java:18) [main/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_25]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_25]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_25]
at java.lang.reflect.Method.invoke(Method.java:483) ~[na:1.8.0_25]
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144) [idea_rt.jar:na]
Caused by: org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type [com.newssystem.lab.dao.Dao] is defined: expected single matching bean but found 2: newsDao,commentDao
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1126) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1014) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:813) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:741) ~[spring-beans-4.2.4.RELEASE.jar:4.2.4.RELEASE]
... 24 common frames omitted
答案 0 :(得分:0)
您必须使用限定符注释来定义将哪个bean注入您的服务。在Spring上,一个接口可以有很多实现,但是如果这些实现都没有定义主要注释,Spring就不知道自动选择哪一个。
@Autowired
@Qualifier("bean-name")