Spring Web App-Autowire-找不到要注入的bean

Question

I have a spring controller with an autowired object that Spring says it can't find, despite my seeing - in the log file - the bean/object for it being created in the root application context. It occurs during the deployment of the application (in Tomcat).

I tried adding @Qualifier to the @Autowired field but it didn't resolve the problem.

Controller:

package com.maha.testspring.endpoints.webrest.controllers;
import com.maha.testspring.services.TestSpringService;

@Controller
@RequestMapping("/testspring")
public class TestSpringController
{
    @Autowired
    @Qualifier("testSpringService")
    private TestSpringService testSpringService;
    ...
}

war's testspring-endpoints-webrest-1.0-SNAPSHOT/ WEB-INF/web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">

    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/spring/root-context.xml</param-value>
    </context-param>

    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>

    <servlet>
        <servlet-name>appServlet</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>/WEB-INF/spring/servlet-context.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>appServlet</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

war's testspring-endpoints-webrest-1.0-SNAPSHOT/ WEB-INF/spring/servlet-context.xml :

<?xml version="1.0" encoding="UTF-8"?>
<beans:beans 
        ...
        <mvc:annotation-driven />
        <context:annotation-config />
        <context:spring-configured />
        <context:component-scan base-package="com.maha.testspring.endpoints.webrest.controllers" />

</beans:beans>

war's testspring-endpoints-webrest-1.0-SNAPSHOT/ WEB-INF/spring/root-context.xml :

<?xml version="1.0" encoding="UTF-8"?>
<beans ...
    <bean class="org.springframework.context.support.ClassPathXmlApplicationContext">
        <constructor-arg>
            <list>
               <value>/applicationContext.testspring.services.xml</value>
            </list>
        </constructor-arg>
    </bean>
</beans>

Service implementation class: (in jar, testspring-services-impl-1.0-SNAPSHOT.jar - in the war's testspring-endpoints-webrest-1.0-SNAPSHOT\\WEB-INF\\lib folder)

package com.maha.testspring.services;
import org.springframework.stereotype.Service;

@Service("testSpringService")
public class TestSpringServiceImpl implements TestSpringService {
    public void testIt() { System.out.println("..."); }
}

Service interface: (in jar, testspring-services-interfaces-1.0-SNAPSHOT.jar - in the war's testspring-endpoints-webrest-1.0-SNAPSHOT\\WEB-INF\\lib folder)

package com.maha.testspring.services;
public interface TestSpringService
{
    public void testIt();
}

applicationContext.testspring.services.xml (in jar, testspring-services-impl-1.0-SNAPSHOT.jar - in the war's testspring-endpoints-webrest-1.0-SNAPSHOT\\WEB-INF\\lib folder)

<?xml version="1.0" encoding="UTF-8"?>
<beans ...>
    <context:spring-configured/>
    <context:annotation-config />
    <context:component-scan base-package="com.maha.testspring.services"/>
</beans>

Logging - shows TestSpringServiceImpl was processed for @Service (as a candidate component when injecting dependency later on)

annotation.ClassPathBeanDefinitionScanner     - Identified candidate component class: URL  [jar:file:/C:/osd/Tomcat%208.0/webapps/testspringwebrest/WEB-INF/lib/testspring-services-impl-1.0-SNAPSHOT.jar!/com/maha/testspring/services/TestSpringServiceImpl.class]
support.ClassPathXmlApplicationContext     -  Bean factory for org.springframework.context.support.ClassPathXmlApplicationContext@41e89deb: org.springframework.beans.factory.support.DefaultListableBeanFactory@7487b2bc

Logging shows creation of bean instance for this class :

support.DefaultListableBeanFactory     - Creating shared instance of singleton bean 'testSpringService'
support.DefaultListableBeanFactory     - Creating instance of bean 'testSpringService'
support.DefaultListableBeanFactory     - Eagerly caching bean 'testSpringService' to allow for resolving potential circular references
support.DefaultListableBeanFactory     - Finished creating instance of bean 'testSpringService'

Error when trying to create the controller - can't find the bean to inject :

support.DefaultListableBeanFactory     - Creating shared instance of singleton bean 'testSpringController'
support.DefaultListableBeanFactory     - Creating instance of bean 'testSpringController'
annotation.InjectionMetadata     - Registered injected element on 
class  [com.maha.testspring.endpoints.webrest.controllers.TestSpringController]:     AutowiredFieldElement for 
private   com.maha.testspring.services.TestSpringService com.maha.testspring.endpoints.webrest.controllers.TestSpringController.testSpringService
annotation.InjectionMetadata     - Processing injected element of bean 'testSpringController': 
AutowiredFieldElement for private 
com.maha.testspring.services.TestSpringService
com.maha.testspring.endpoints.webrest.controllers.TestSpringController.testSpringService

support.XmlWebApplicationContext     - Exception encountered during context initialization - cancelling refresh attempt
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'testSpringController': 
Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: 
Could not autowire field: private   com.maha.testspring.services.TestSpringService com.maha.testspring.endpoints.webrest.controllers.TestSpringController.testSpringService; 
nested exception is 
org.springframework.beans.factory.NoSuchBeanDefinitionException: 
No qualifying bean of type
[com.maha.testspring.services.TestSpringService] found for dependency: 
expected at least 1 bean which qualifies as autowire candidate for this dependency.

Answer 1

I had a similar problem . We solved it by keeping the CASE same . In your example you used @Qualifier("testSpringService") and your yout service public class TestSpringServiceImpl implements TestSpringService

TRY changing it to public class TestSpringServiceImpl implements testSpringService with a SMALL t in testSpringService.

If that dont solve your problem then try annotating the parent class (Remember that annotations are not inherited from parent class to the child and in your case you have annotated the child and not its parent ) like :

package com.maha.testspring.services;
@Service("testSpringService")
public interface TestSpringService
{
    public void testIt();
}