java - 无法 Autowiring 字段(Spring mvc - 注释)

Question

我无法解决注入(inject) Spring bean 的问题。我使用 jar 模块(有服务、dao、ropositories ...)和 war 模块(有 Controller 和应用程序配置)创建了多模块项目。当我在 Jboss 上启动应用程序时，出现以下异常:

Context initialization failed: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'login': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private com.engineering.pawel.service.UserService com.engineering.pawel.controller.Login.userService; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'userService': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private com.engineering.pawel.repository.UserRepository com.engineering.pawel.service.UserService.userRepository; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.engineering.pawel.repository.UserRepository] 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)}

这是我的 web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app 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_3_0.xsd"
    version="3.0">

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

    <!-- ........................................................................... -->
    <!-- Spring Security -->
    <!-- ........................................................................... -->
    <filter>
        <filter-name>springSecurityFilterChain</filter-name>
        <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
    </filter>

    <filter-mapping>
        <filter-name>springSecurityFilterChain</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

    <persistence-unit-ref>
        <persistence-unit-ref-name>persistence/my-emf</persistence-unit-ref-name>
        <persistence-unit-name>my-jpa</persistence-unit-name>
    </persistence-unit-ref>

</web-app>

下面是servlet-context.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans:beans xmlns="http://www.springframework.org/schema/mvc"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:beans="http://www.springframework.org/schema/beans"
    xmlns:tx="http://www.springframework.org/schema/tx" xmlns:context="http://www.springframework.org/schema/context"
    xmlns:jee="http://www.springframework.org/schema/jee"
    xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd
        http://www.springframework.org/schema/tx
        http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
        http://www.springframework.org/schema/jee
        http://www.springframework.org/schema/jee/spring-jee-4.0.xsd">


    <!-- Enables the Spring MVC @Controller programming model -->

    <annotation-driven />
    <context:annotation-config />

    <!-- Handles HTTP GET requests for /resources by efficiently serving 
        up static resources in the ${webappRoot}/resources directory -->
    <resources mapping="/resources/**" location="/resources/" />

    <!-- Resolves views selected for rendering by @Controllers to .jsp resources 
        in the /WEB-INF/views directory -->
    <beans:bean
        class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <beans:property name="prefix" value="/WEB-INF/views/" />
        <beans:property name="suffix" value=".jsp" />
    </beans:bean>

    <!-- Configure to plugin JSON as request and response in method handler -->
    <beans:bean
        class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter">
        <beans:property name="messageConverters">
            <beans:list>
                <beans:ref bean="jsonMessageConverter" />
            </beans:list>
        </beans:property>
    </beans:bean>

    <!-- Configure bean to convert JSON to POJO and vice versa -->
    <beans:bean id="jsonMessageConverter"
        class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
    </beans:bean>

    <context:component-scan base-package="com.engineering.pawel" />


    <!-- Database configuration -->
    <jee:jndi-lookup id="dataSource" jndi-name="java:jboss/datasources/postgreSQL"
        resource-ref="true" />

    <jee:jndi-lookup id="entityManagerFactory" jndi-name="java:comp/env/persistence/my-emf"
        expected-type="javax.persistence.EntityManagerFactory" />

    <beans:bean id="transactionManager"
        class="org.springframework.transaction.jta.JtaTransactionManager">
        <beans:property name="transactionManagerName" value="java:/TransactionManager" />
    </beans:bean>

    <beans:bean class="org.springframework.orm.hibernate4.HibernateExceptionTranslator" />
</beans:beans>

下面是UserRepository.java

package com.engineering.pawel.repository;

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

import com.engineering.pawel.pojo.User;

@Repository
public interface UserRepository extends JpaRepository<User,Integer>{
    
}

下面是UserService.java

@Service
@Transactional
public class UserService {
    
    @Autowired
    private UserRepository userRepository;
    
    public void addUser(final String userNick, final String userPassword){
        final User user = new User();
        user.setNick(userNick);
        user.setPassword(userPassword);
        userRepository.saveAndFlush(user);
    }
    
    public List<User> getUsers(){
        return this.userRepository.findAll();
    }

}

这是登录类:

@Controller
public class Login {
    
    @Autowired
    private UserService userService;
}

我将非常感谢您的帮助。

Answer 1

仔细观察你的异常会告诉你一切:

NoSuchBeanDefinitionException: No qualifying bean of type 
   [com.engineering.pawel.repository.UserRepository] found for dependency:
   expected at least 1 bean which qualifies as autowire candidate for this dependency. 

这仅仅意味着:

@Repository
public interface UserRepository extends JpaRepository<User,Integer>{

}

和

@Service
@Transactional
public class UserService {

    @Autowired
    private UserRepository userRepository;  // Here you need to have a Bean 
                    // Implementing this UserRepository as an autowire candidate
    ...
}

Spring Context Loader 没有找到 UserRepository 的子类。