Question

我有一个注入以下类的资源

@Component
public class CustomDozerBeanMapper implements Mapper {
    private final DozerBeanMapper beanMapper;

    public CustomDozerBeanMapper() {
        this.beanMapper = new DozerBeanMapper();
        BeanMappingBuilder builder = new BeanMappingBuilder() {
            protected void configure() {
                //some mapping stuff
            }
        };
        beanMapper.addMapping(builder);
    }

    @Override
    public <T> T map(Object o, Class<T> aClass) throws MappingException {
        return beanMapper.map(o, aClass);
    }

    @Override
    public void map(Object o, Object o1) throws MappingException {
        beanMapper.map(o, o1);
    }

    @Override
    public <T> T map(Object o, Class<T> aClass, String s) throws MappingException {
        return beanMapper.map(o, aClass, s);
    }

    @Override
    public void map(Object o, Object o1, String s) throws MappingException {
        beanMapper.map(o, o1, s);
    }
}

在我的applicationContext.xml中，我声明了

<context:annotation-config/>
<context:component-scan base-package="foo.bar"/>
<bean id="customDozerMapper" class="foo.bar.CustomDozerBeanMapper" />

然后在我们的资源中我注入它

class SomeResource {
   @Inject CustomDozerMapper customDozerMapper;

   //We have loads of other Injects which work just fine, only this class has problems
}

Caused by: A MultiException has 1 exceptions.  They are:
1. org.glassfish.hk2.api.UnsatisfiedDependencyException: There was no object available for injection at SystemInjecteeImpl(requiredType=CustomDozerBeanMapper,parent=SomeResource,qualifiers={},position=-1,optional=false,self=false,unqualified=null,1098507248)

    at org.jvnet.hk2.internal.ThreeThirtyResolver.resolve(ThreeThirtyResolver.java:75)
    at org.jvnet.hk2.internal.Utilities.justInject(Utilities.java:947)
    at org.jvnet.hk2.internal.ServiceLocatorImpl.inject(ServiceLocatorImpl.java:975)
    at org.jvnet.hk2.internal.ServiceLocatorImpl.inject(ServiceLocatorImpl.java:965)
    at org.glassfish.jersey.server.spring.SpringComponentProvider$SpringManagedBeanFactory.provide(SpringComponentProvider.java:191)
    at org.jvnet.hk2.internal.FactoryCreator.create(FactoryCreator.java:153)
    at org.jvnet.hk2.internal.SystemDescriptor.create(SystemDescriptor.java:471)
    at org.jvnet.hk2.internal.PerLookupContext.findOrCreate(PerLookupContext.java:70)
    at org.jvnet.hk2.internal.Utilities.createService(Utilities.java:2072)
    at org.jvnet.hk2.internal.ServiceLocatorImpl.internalGetService(ServiceLocatorImpl.java:761)
    at org.jvnet.hk2.internal.ServiceLocatorImpl.getService(ServiceLocatorImpl.java:700)
    at org.glassfish.jersey.internal.inject.Injections.getOrCreate(Injections.java:172)
    at org.glassfish.jersey.server.model.MethodHandler$ClassBasedMethodHandler.getInstance(MethodHandler.java:284)
    at org.glassfish.jersey.server.internal.routing.PushMethodHandlerRouter.apply(PushMethodHandlerRouter.java:74)
    at org.glassfish.jersey.server.internal.routing.RoutingStage._apply(RoutingStage.java:109)
    at org.glassfish.jersey.server.internal.routing.RoutingStage._apply(RoutingStage.java:112)
    at org.glassfish.jersey.server.internal.routing.RoutingStage._apply(RoutingStage.java:112)

现在如果我改变并使用@Autowired，它可以正常工作我们使用Spring进行依赖关系管理，但由于某种原因，正在使用h2k，我得到以下异常

任何人都可以解释一下可能出现的问题吗？

为什么它适用于@Autowired而非@Inject

为什么要使用h2k，而不是Spring？

Answer 1

问题可能是因为2个bean声明（一个在XML配置中，另一个在@Component中）并且DI容器无法接收其中一个。

此处提供的所有解决方案：

删除其中一个bean定义（我更喜欢XML）
通过@Qualifier或@Named注释

Answer 2

问题可能还在于配置文件customDozerMapper中的bean名称和实际注入customerDozerMapper不匹配。如果@inject找不到匹配的bean，则会抛出异常。但是，可以设置@autowired，其中您可以设置属性required=false，如果找不到匹配的bean，则会注入null。

注意：config xml中的配置会覆盖注释配置。

@Autowired工作但不是@Inject

2 个答案: