我试图弄清楚如何使用 @Autowired 注释在 Spring 中进行模拟实现。我正在尝试通过配置文件来驱动它：
- 有一个默认配置文件在未定义配置时运行
- 当指定测试配置文件时，它将自动装配模拟对象而不是默认实现。
在追求这个设置时，我遇到了一个问题，即 Spring 似乎无法区分我的实现之间的区别。我正在使用 Tomcat/Jersey/Maven/Spring 并且没有使用任何 xml 配置。以下是相关代码的概要（可在我的示例 GitHub 上查看）。
问题：运行它mvn clean tomcat7:run并导航到 '/foo/bar' 会产生以下异常（下面的完整堆栈跟踪）：No qualifying bean of type [dkwestbr.spring.autowired.example.IStringGetter] is defined: expected single matching bean but found 2: a,b
我意识到问题是 Spring 无法区分我的两个实现，但是我很难找到如何正确声明我需要 a 默认情况下，并且 b 只有在运行时才需要mvn test。
我的初始化程序：
@Override
public void onStartup(ServletContext context) throws ServletException {
AnnotationConfigWebApplicationContext appContext = new AnnotationConfigWebApplicationContext();
appContext.register(AppConfig.class);
context.addListener(new ContextLoaderListener(appContext));
/*
for(String profile: appContext.getEnvironment().getActiveProfiles()) {
System.out.println(String.format("Active profile: %s", profile));
}
*/
Map<String, String> filterParameters = new HashMap<>();
// set filter parameters
filterParameters.put("com.sun.jersey.config.property.packages", "dkwestbr.spring.autowired.example");
filterParameters.put("com.sun.jersey.config.property.JSPTemplatesBasePath", "/WEB-INF/app");
filterParameters.put("com.sun.jersey.config.property.WebPageContentRegex", "/(images|css|jsp)/.*");
SpringServlet servlet = new SpringServlet();
ServletRegistration.Dynamic servletDispatcher = context.addServlet("jersey-servlet", servlet);
servletDispatcher.setInitParameters(filterParameters);
servletDispatcher.setLoadOnStartup(1);
servletDispatcher.addMapping("/*");
}
我的配置：
@Configuration
@ComponentScan(basePackages = {"dkwestbr.spring.autowired.example"})
public class AppConfig {
@Bean
private static PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer() {
return new PropertySourcesPlaceholderConfigurer();
}
@Configuration
@PropertySource("classpath:configuration.properties")
static class Production { }
@Configuration
@Profile("test")
@PropertySource("classpath:configuration.properties")
static class Test { }
}
我的 Web 端点具有相关@Autowired变量：
@Path("/foo")
@Component
public class WebEndpoint {
@Autowired
private IStringGetter getTheThing;
@GET
@Path("/bar")
@Produces(MediaType.TEXT_HTML)
public String getStuff() {
System.out.println(getTheThing.getItGood());
return String.format("<html><body>Hello - %s</body></html>", getTheThing.getItGood());
}
}
我的第一个实现（我希望这是默认的）：
@Component
public class A implements IStringGetter {
@Value("${my.property}")
private String configValue;
@Override
public String getItGood() {
return String.format("I am an A: %s", configValue);
}
}
我的第二个实现（我只在运行时想要这个mvn test）：
@Component
@ActiveProfiles("test")
public class B implements IStringGetter {
@Value("${my.property}")
private String configValue;
@Override
public String getItGood() {
return String.format("I am an B: %s", configValue);
}
}
完整的堆栈跟踪：
10:22:49.136 [localhost-startStop-1] ERROR org.springframework.web.context.ContextLoader - Context initialization failed
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'webEndpoint': Injection of autowired dependencies failed; nes
ted exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private dkwestbr.spring.autowired.example.IString
Getter dkwestbr.spring.autowired.example.WebEndpoint.getTheThing; nested exception is org.springframework.beans.factory.NoUniqueBeanDefinitionExcepti
on: No qualifying bean of type [dkwestbr.spring.autowired.example.IStringGetter] is defined: expected single matching bean but found 2: a,b
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostPro
cessor.java:288) ~[spring-beans-3.2.4.RELEASE.jar:3.2.4.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1116) ~[
spring-beans-3.2.4.RELEASE.jar:3.2.4.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:519) ~[s
pring-beans-3.2.4.RELEASE.jar:3.2.4.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:458) ~[spr
ing-beans-3.2.4.RELEASE.jar:3.2.4.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:295) ~[spring-beans-3.2.4.RELEASE.jar:3
.2.4.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223) ~[spring-beans-
3.2.4.RELEASE.jar:3.2.4.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:292) ~[spring-beans-3.2.4.RELEASE.jar:3.2
.4.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194) ~[spring-beans-3.2.4.RELEASE.jar:3.2.4
.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:628) ~[sprin
g-beans-3.2.4.RELEASE.jar:3.2.4.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:932) ~[spri
ng-context-3.2.4.RELEASE.jar:3.2.4.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:479) ~[spring-context-3.2.4.RELEASE
.jar:3.2.4.RELEASE]
at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:389) ~[spring-web-3.2.4.RELEASE.
jar:3.2.4.RELEASE]
at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:294) [spring-web-3.2.4.RELEASE.jar:3.2.4.RELEAS
E]
at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:112) [spring-web-3.2.4.RELEASE.jar:3.2
.4.RELEASE]
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4797) [tomcat-embed-core-7.0.37.jar:7.0.37]
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5291) [tomcat-embed-core-7.0.37.jar:7.0.37]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) [tomcat-embed-core-7.0.37.jar:7.0.37]
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1559) [tomcat-embed-core-7.0.37.jar:7.0.37]
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1549) [tomcat-embed-core-7.0.37.jar:7.0.37]
at java.util.concurrent.FutureTask.run(FutureTask.java:262) [?:1.7.0_40]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [?:1.7.0_40]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [?:1.7.0_40]
at java.lang.Thread.run(Thread.java:724) [?:1.7.0_40]
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: private dkwestbr.spring.autowired.example.IStringGetter
dkwestbr.spring.autowired.example.WebEndpoint.getTheThing; nested exception is org.springframework.beans.factory.NoUniqueBeanDefinitionException: No
qualifying bean of type [dkwestbr.spring.autowired.example.IStringGetter] is defined: expected single matching bean but found 2: a,b
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPost
Processor.java:514) ~[spring-beans-3.2.4.RELEASE.jar:3.2.4.RELEASE]
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87) ~[spring-beans-3.2.4.RELEASE.jar:3.2.4.RE
LEASE]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostPro
cessor.java:285) ~[spring-beans-3.2.4.RELEASE.jar:3.2.4.RELEASE]
... 22 more
Caused by: org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type [dkwestbr.spring.autowired.example.IStringGe
tter] is defined: expected single matching bean but found 2: a,b
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:865) ~[spring-bea
ns-3.2.4.RELEASE.jar:3.2.4.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:770) ~[spring-beans
-3.2.4.RELEASE.jar:3.2.4.RELEASE]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPost
Processor.java:486) ~[spring-beans-3.2.4.RELEASE.jar:3.2.4.RELEASE]
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87) ~[spring-beans-3.2.4.RELEASE.jar:3.2.4.RE
LEASE]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostPro
cessor.java:285) ~[spring-beans-3.2.4.RELEASE.jar:3.2.4.RELEASE]
... 22 more
Oct 11, 2013 10:22:49 AM org.apache.catalina.core.StandardContext listenerStart
SEVERE: Exception sending context initialized event to listener instance of class org.springframework.web.context.ContextLoaderListener
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'webEndpoint': Injection of autowired dependencies failed; nes
ted exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private dkwestbr.spring.autowired.example.IString
Getter dkwestbr.spring.autowired.example.WebEndpoint.getTheThing; nested exception is org.springframework.beans.factory.NoUniqueBeanDefinitionExcepti
on: No qualifying bean of type [dkwestbr.spring.autowired.example.IStringGetter] is defined: expected single matching bean but found 2: a,b
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostPro
cessor.java:288)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1116)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:519)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:458)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:295)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:292)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:628)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:932)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:479)
at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:389)
at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:294)
at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:112)
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4797)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5291)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1559)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1549)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:724)
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: private dkwestbr.spring.autowired.example.IStringGetter
dkwestbr.spring.autowired.example.WebEndpoint.getTheThing; nested exception is org.springframework.beans.factory.NoUniqueBeanDefinitionException: No
qualifying bean of type [dkwestbr.spring.autowired.example.IStringGetter] is defined: expected single matching bean but found 2: a,b
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPost
Processor.java:514)
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostPro
cessor.java:285)
... 22 more
Caused by: org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type [dkwestbr.spring.autowired.example.IStringGe
tter] is defined: expected single matching bean but found 2: a,b
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:865)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:770)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPost
Processor.java:486)
... 24 more