java - Spring Converter 复杂对象

Question

我在 Spring 4.0 中遇到转换服务问题如何在转换器中调用转换服务？

我的配置:

@Configuration
@ComponentScan...
@EnableAspectJAutoProxy
@EnableWebMvc
public class WebMvcConfig extends WebMvcConfigurerAdapter {
    @Autowired
    private Converter1 converter1;
    @Autowired
    private Converter2 converter2;
    @Override
    public void addFormatters(FormatterRegistry registry) {

       registry.addConverter(converter1);
       registry.addConverter(converter2);

    }
    .....
}

我的转换器:

@Component
public class Converter1 implements Converter <SourceObject, TargetObjec>{
    @Autowired
    private org.springframework.core.convert.ConversionService conv
    @Override
    public TargetObjec convert(SourceObject source) {
        .......
        conv.convert(source.childObject, Target2.class);
    }
}

@Component
public class Converter2 implements Converter <ChildObject, Target2>{

    @Override
    public TargetObjec2 convert(ChildObject source) {
        .......

    }
}

在 Controller 中我收到SourceObject

@Controller
public class SourceObjectReciver {

   @Autowired
   ConversionService conv;

  @RequestMapping(value="/new", method={RequestMethod.POST})
  @ResponseBody
  public ResponseEntity<InterfaceStatus> createObject(@RequestBody SourceObject source, BindingResult br) {

    conv.convert(source, TargetObjec.class);
    ...

  }

}

TargetObject 和 ChildObject 是一个实体，并且它们是相关的

.......
public class TargetObject ....{
 ......
 private ChildObject child;
}

Tomcat 无法加载 Web 应用程序，我遇到错误

> 
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'webMvcConfig': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private converter.Converter1 it.equipnet.GFInterface.config.WebMvcConfig.Converter1; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'Converter1': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private org.springframework.core.convert.ConversionService converter.Converter1.conv; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'mvcConversionService' defined in class path resource [org/springframework/web/servlet/config/annotation/DelegatingWebMvcConfiguration.class]: Instantiation of bean failed; nested exception is org.springframework.beans.factory.BeanDefinitionStoreException: Factory method [public org.springframework.format.support.FormattingConversionService org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport.mvcConversionService()] threw exception; nested exception is java.lang.NullPointerException
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:292)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1185)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:537)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:304)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:195)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:700)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:760)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:482)
    at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:403)
    at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:306)
    at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:106)
    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:5014)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5524)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1575)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1565)
    at java.util.concurrent.FutureTask.run(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: private converter.Converter1 config.WebMvcConfig.Converter1; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'Converter1': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private org.springframework.core.convert.ConversionService converter.Converter1.conv; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'mvcConversionService' defined in class path resource [org/springframework/web/servlet/config/annotation/DelegatingWebMvcConfiguration.class]: Instantiation of bean failed; nested exception is org.springframework.beans.factory.BeanDefinitionStoreException: Factory method [public org.springframework.format.support.FormattingConversionService org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport.mvcConversionService()] threw exception; nested exception is java.lang.NullPointerException
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:508)
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:289)
    ... 22 more
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'Converter1': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private org.springframework.core.convert.ConversionService converter.Converter1.conv; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'mvcConversionService' defined in class path resource [org/springframework/web/servlet/config/annotation/DelegatingWebMvcConfiguration.class]: Instantiation of bean failed; nested exception is org.springframework.beans.factory.BeanDefinitionStoreException: Factory method [public org.springframework.format.support.FormattingConversionService org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport.mvcConversionService()] threw exception; nested exception is java.lang.NullPointerException
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:292)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1185)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:537)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:304)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:195)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:1014)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:957)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:855)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:480)
    ... 24 more
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: private org.springframework.core.convert.ConversionService converter.Converter1.conv; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'mvcConversionService' defined in class path resource [org/springframework/web/servlet/config/annotation/DelegatingWebMvcConfiguration.class]: Instantiation of bean failed; nested exception is org.springframework.beans.factory.BeanDefinitionStoreException: Factory method [public org.springframework.format.support.FormattingConversionService org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport.mvcConversionService()] threw exception; nested exception is java.lang.NullPointerException
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:508)
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:289)
    ... 35 more
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'mvcConversionService' defined in class path resource [org/springframework/web/servlet/config/annotation/DelegatingWebMvcConfiguration.class]: Instantiation of bean failed; nested exception is org.springframework.beans.factory.BeanDefinitionStoreException: Factory method [public org.springframework.format.support.FormattingConversionService org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport.mvcConversionService()] threw exception; nested exception is java.lang.NullPointerException
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:592)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1094)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:989)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:504)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:304)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:195)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:1014)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:957)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:855)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:480)
    ... 37 more
Caused by: org.springframework.beans.factory.BeanDefinitionStoreException: Factory method [public org.springframework.format.support.FormattingConversionService org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport.mvcConversionService()] threw exception; nested exception is java.lang.NullPointerException
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:188)
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:581)
    ... 49 more
Caused by: java.lang.NullPointerException
    at org.springframework.core.convert.support.GenericConversionService.getRequiredTypeInfo(GenericConversionService.java:270)
    at org.springframework.core.convert.support.GenericConversionService.addConverter(GenericConversionService.java:84)
    at it.equipnet.GFInterface.config.WebMvcConfig.addFormatters(WebMvcConfig.java:47)
    at org.springframework.web.servlet.config.annotation.WebMvcConfigurerComposite.addFormatters(WebMvcConfigurerComposite.java:49)
    at org.springframework.web.servlet.config.annotation.DelegatingWebMvcConfiguration.addFormatters(DelegatingWebMvcConfiguration.java:100)
    at org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport.mvcConversionService(WebMvcConfigurationSupport.java:403)
    at org.springframework.web.servlet.config.annotation.DelegatingWebMvcConfiguration$$EnhancerByCGLIB$$a7f438f4.CGLIB$mvcConversionService$20(<generated>)
    at org.springframework.web.servlet.config.annotation.DelegatingWebMvcConfiguration$$EnhancerByCGLIB$$a7f438f4$$FastClassByCGLIB$$3ea3412c.invoke(<generated>)
    at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:228)
    at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:326)
    at org.springframework.web.servlet.config.annotation.DelegatingWebMvcConfiguration$$EnhancerByCGLIB$$a7f438f4.mvcConversionService(<generated>)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:166)
    ... 50 more

Answer 1

我自己找到了解决方案。在 webConfig 中我添加了代码

.......
public void addFormatters(FormatterRegistry registry) {
    ConversionService conversionService = (ConversionService) registry;
    om3000PickupConverter.setConv(conversionService);

    registry.addConverter(objectConverter);
    registry.addConverter(childConverter);

}
.....

在转换器1中我添加了

private ConversionService conv;

public void setConv(ConversionService conv) {
    this.conv = conv;
}

当我调用 conv.converter 时，它会调用 Convert2 的正确方法