自动装配不适用于 @RestController

Question

我需要创建一个简单的 REST 服务，其中包含一些我想从 applicatonContext.xml 文件中导出的字段，但我已经有了

堆栈跟踪

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 's3RestController': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private java.lang.String com.emc.sk.data_mgmt_central.server.S3RestController.path; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [java.lang.String] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true), @org.springframework.beans.factory.annotation.Qualifier(value=path)}
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:334)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1204)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:538)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:476)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:302)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:229)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:298)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:725)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:757)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:480)
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:109)
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:691)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:320)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:952)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:941)
at com.emc.sk.data_mgmt_central.main.Main.main(Main.java:39)

Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: private java.lang.String com.emc.sk.data_mgmt_central.server.S3RestController.path; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [java.lang.String] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true), @org.springframework.beans.factory.annotation.Qualifier(value=path)}
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:555)
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:331)
... 16 common frames omitted

Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [java.lang.String] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true), @org.springframework.beans.factory.annotation.Qualifier(value=path)}
at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoSuchBeanDefinitionException(DefaultListableBeanFactory.java:1261)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1009)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:904)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:527)
... 18 common frames omitted

我运行应用程序

主类

@ComponentScan("com.emc.sk.data_mgmt_central.server")
@EnableAutoConfiguration
public class Main {
    public static void main(String[] args) {    
        SpringApplication.run(Main.class, args);   
    }
}

这是我的

RestController

@RestController
@ContextConfiguration("/FileStorageContext.xml")
public class S3RestController {

@Autowired
private String path;

@RequestMapping("/getBucket")
public Bucket getBucket(@RequestParam(value="name", defaultValue="world") String name) {
    return new Bucket(name);
}   
}

我的 applicationContext 称为 FileStorageContext 并存储在 src/main/recourses 中（我有一个 maven 项目）

FileStorageContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans      http://www.springframework.org/schema/beans/spring-beans.xsd">

<bean name = "path" class="java.lang.String">
    <constructor-arg type="java.lang.String" value="#{ systemProperties['java.io.tmpdir'] }bucketDir" />
</bean>

@Autowired 在我的测试中可以正常工作，但这里会出现此错误。我是春天的新手，也许这种构造根本不正确。谢谢。

Answer 1

添加@PropertySource("classpath:/your/properties/path/applicatio.properties") 到您的控制器并将@Value标签添加到路径而不是@Autowired。

@Value("${java.io.tmpdir}")
private String path;

Answer 2

我不得不把 @ImportResource("classpath:/FileStorageContext.xml") 在我的 Main 类之前，问题是没有看到这个文件。

Answer 3

这行导致你的异常：

@Autowired
private String path;

自动装配仅适用于 Spring 托管 bean，String 不应被视为一个 (IMO)。

如果你想从你的上下文中获取path 的值，你可以使用@Value 注解。或者，如果您想按原样使用，可以尝试使用 @Qualifier("path") 注释和 @Autowired。