我有一个具有如下实现的接口：
public interface Vehicle<T> {
void stuff(T param);
}
@Component
public class Car<T> implements Vehicle<T> {
private final Strategy<T> strat;
public Car(@Lazy Strategy strat) {
this.strat = strat;
}
void stuff(T param) {
strat.stuff(param);
}
}
策略接口/类看起来像这样：
public interface Strategy<T> {
void stuff(T param);
}
@Component
public class FooAStrategy implements Strategy<FooA> {
void stuff(FooA param) { //do stuff }
}
@Component
public class FooBStrategy implements Strategy<FooB> {
void stuff(FooABparam) { //do stuff }
}
最后，我有一个这样的服务类：
@Service
public class ServiceClassA {
private FooA fooA;
private FooB fooB;
private FooC fooC;
private Vehicle<FooD> vehicle; //how to inject correct implementation?
public ServiceClass(FooA fooA, FooB fooB, FooC fooC) {
this.fooA = fooA;
this.fooB = fooB;
this.fooC = fooC;
}
}
@Service
public class ServiceClassB {
private FooA fooA;
private FooB fooB;
private FooC fooC;
private Vehicle<FooE> vehicle; //how to inject correct implementation?
public ServiceClass(FooA fooA, FooB fooB, FooC fooC) {
this.fooA = fooA;
this.fooB = fooB;
this.fooC = fooC;
}
}
基本上，对于第一个服务类ServiceClassA，我想这样做：
Strategy strat = new FooAStrategy();
Vehicle vehicle = new Car(strat);
ServiceClassA class = new ServiceClassA(fooA, fooB, fooC, vehicle);
但每次运行应用程序时都会出现此错误：
org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type 'com.test.notification.Strategy<?>' available: expected single matching bean but found 2: fooAStrategy,fooBStrategy
at org.springframework.beans.factory.config.DependencyDescriptor.resolveNotUnique(DependencyDescriptor.java:173)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1116)
at org.springframework.context.annotation.ContextAnnotationAutowireCandidateResolver$1.getTarget(ContextAnnotationAutowireCandidateResolver.java:83)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:192)
at com.sun.proxy.$Proxy259.generateNotifications(Unknown Source)
at com.test.notification.RabbitMQEventPublisher.process(RabbitMQEventPublisher.java:24)
at com.test.services.ServiceClassA.testConncetion(ServiceClassA.java:400)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:333)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:207)
at com.sun.proxy.$Proxy260.testConnection(Unknown Source)
at com.test.controllers.ControllerTest.get(ControllerTest.java:130)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:97)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:635)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:317)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:127)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:91)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:114)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:137)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:111)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:170)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:63)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at com.test.security.jwt.JwtTokenAuthenticationProcessingFilter.successfulAuthentication(JwtTokenAuthenticationProcessingFilter.java:52)
at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:240)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:200)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:116)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:64)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:105)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:56)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.web.filter.CorsFilter.doFilterInternal(CorsFilter.java:96)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:331)
at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:214)
at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:177)
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346)
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:262)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:799)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:861)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1455)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
由于我让spring引导使用@Component注释和构造函数自行连接所有内容，因此我没有任何配置类。我不知道如何指定1依赖的具体实现。
最好的方法是什么？
答案 0 :(得分：0)
从汽车中移除@Component并注入工厂。就像消息所说，Spring对于需要创建的东西是不明确的。一种解决方案是通过工厂自己创建汽车，例如FooACarFactory（可以实现通用FooAVehicleFactory）。您可以让Spring创建FooACarFactory并将其注入到具有vehicle = fooAVehicleFactory.create()的服务构造函数中。注意：如果组件扫描路径上同时包含FooACarFactory和FooATruckFactory，则可以使用@Kenny提到的@Primary注释强制Spring注入所需的注释。或者将jar与正确的实现放在java类路径中。
或者，您可以拥有一个通用工厂，而不是创建汽车工厂的变种：
@Component
public class VehicleFactory {
@Autowired
FooAStrategy fooAStrategy;
@Autowired
FooBStrategy fooBStrategy;
boolean buildTruck = true; //get from external system parameter instead
public <T> Vehicle<T> getObject(Class<?> clazz) throws Exception {
if (clazz.equals(FooA.class)) {
if (buildTruck) {
return (Vehicle<T>) new Truck<FooA>(fooAStrategy);
}
return (Vehicle<T>) new Car<FooA>(fooAStrategy);
}
return (Vehicle<T>) new Car<FooB>(fooBStrategy);
}
然后在服务类中：
@Service
public class ServiceClassA {
private FooA fooA;
private FooB fooB;
private Vehicle<FooA> vehicle;
@Autowired
public ServiceClassA(
FooA fooA, FooB fooB,
CarFactory vehicleFactory
) throws Exception {
this.fooA = fooA;
this.fooB = fooB;
this.vehicle = vehicleFactory.<FooA>getObject(FooA.class);
}
}
答案 1 :(得分：-1)
作为您的评论，我想纠正答案。这也是一样的想法。使用@Primary，@Component和@Resource。
@Primary
@Component("car")
public class Car<T> implements Vehicle<T> {
//...
}
在使用车辆时，看起来像是：
@Service
public class ServiceClassA {
private FooA fooA;
private FooB fooB;
private FooC fooC;
@Resource(name="car")
private Vehicle<FooA> vehicle;
...
}
@Primary
@Component("fooAStrategy")
public class FooAStrategy implements Strategy<FooA> {
}
@Component("fooBStrategy")
public class FooBStrategy implements Strategy<FooB> {
}
希望得到这个帮助。