Spring Autowiring Service在我的Controller中不起作用 [英] Spring Autowiring Service doesn't work in my Controller

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问题描述

我有问题，以便在我的控制器中自动装配服务。我有这个错误：

i've problems in order to autowire a service in my controller. I've this error:

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'myController': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private es.unican.meteo.service.UserService es.unican.meteo.controller.MyController.userService; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No matching bean of type [es.unican.meteo.service.UserService] 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)}

似乎userService未注册，因此，控制器无法获取bean。我认为我的配置没问题，因为它适用于测试。在测试中我有这个：

It seems that the userService is not registered, so that, the controller can't get the bean. I thought that my config was ok because it works with the tests. In the tests i have this:

ClassPathXmlApplicationContext("/WEB-INF/app-config.xml");

我可以从ApplicationContext.xml中获取bean

and i can get the bean ok from the ApplicationContext.xml

我的包结构如下：

es.unican.meteo.controller

es.unican.meteo.controller

| ---- MyController.java

|---- MyController.java

es.unican.meteo.service

es.unican.meteo.service

| ---- UserService.java

|---- UserService.java

es.unican.meteo.service.impl

es.unican.meteo.service.impl

| ---- UserServiceImpl.java

|---- UserServiceImpl.java

.....

WebContent / WEB-INF

WebContent/WEB-INF

| ---- MyDispatcherServlet-servlet.xml

|---- MyDispatcherServlet-servlet.xml

| ---- app-config.xml

|---- app-config.xml

| ---- web.xml

|---- web.xml

.....

：

== UserServiceImpl.java ==

== UserServiceImpl.java ==

@Service
public class UserServiceImpl implements UserService{

    @Autowired
    private UserMapper userMapper;

    public void setUserMapper(UserMapper userMapper) {
        this.userMapper = userMapper;
    }

== MyController.java ==

== MyController.java ==

@Controller
public class MyController {

     @Autowired
     private UserService userService;

     @RequestMapping(method=RequestMethod.GET, value="/home")
     public String handleRequest(){
      return "welcome";
     }

     @RequestMapping(method=RequestMethod.GET, value="/getUsers")
     public @ResponseBody List<User> getUsersInJSON(){
      return userService.getUsers();
     }
}

== web.xml ==

== web.xml ==

<display-name>Spring MVC</display-name>

 <servlet>
  <servlet-name>MyDispatcherServlet</servlet-name>
  <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
 </servlet>

 <servlet-mapping>
  <servlet-name>MyDispatcherServlet</servlet-name>
  <url-pattern>*.go</url-pattern>
 </servlet-mapping>
</web-app>

== app-config.xml ===

== app-config.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"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:p="http://www.springframework.org/schema/p"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd
        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd">


   <!-- Scans the classpath of this application for @Components to deploy as beans -->
   <context:component-scan base-package="es.unican.meteo" />

   <!-- Configures the @Controller programming model -->
   <mvc:annotation-driven/>

   <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource"
    p:driverClassName="org.apache.derby.jdbc.EmbeddedDriver"
    p:url="jdbc:derby:C:\tools\derbydb"
    p:connectionProperties=""
    p:username="APP"
    p:password="" />

    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"/>
    </bean>

    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <property name="configLocation" value="/mybatis-config.xml" />
    </bean> 

    <bean id="usersMapper" class="org.mybatis.spring.mapper.MapperFactoryBean">
        <property name="mapperInterface" value="es.unican.meteo.dao.UserMapper" />
        <property name="sqlSessionFactory" ref="sqlSessionFactory" />
    </bean> 

    <bean id="rolesMapper" class="org.mybatis.spring.mapper.MapperFactoryBean">
        <property name="mapperInterface" value="es.unican.meteo.dao.RoleMapper" />
        <property name="sqlSessionFactory" ref="sqlSessionFactory" />
    </bean> 

</beans>

== MyDispatcherServlet.xml ==

== MyDispatcherServlet.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"
 xmlns:context="http://www.springframework.org/schema/context"
 xmlns:mvc="http://www.springframework.org/schema/mvc"
 xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
  http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd
  http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd">

 <!-- Enabling Spring beans auto-discovery -->
 <context:component-scan base-package="es.unican.meteo.controller" />

 <!-- Enabling Spring MVC configuration through annotations -->
 <mvc:annotation-driven />

 <!-- Defining which view resolver to use -->
 <bean class= "org.springframework.web.servlet.view.InternalResourceViewResolver" > 
  <property name="prefix" value="/WEB-INF/views/" /> 
  <property name="suffix" value=".jsp" /> 
 </bean>

Spring mvc logger trace：

Spring mvc logger trace:

19:38:54,119 DEBUG http-8080-1 support.DefaultListableBeanFactory:430 - Creating instance of bean 'myController'
19:38:54,170 DEBUG http-8080-1 annotation.InjectionMetadata:60 - Found injected element on class [es.unican.meteo.controller.MyController]: AutowiredFieldElement for private es.unican.meteo.service.UserService es.unican.meteo.controller.MyController.userService
19:38:54,174 DEBUG http-8080-1 support.DefaultListableBeanFactory:504 - Eagerly caching bean 'myController' to allow for resolving potential circular references
19:38:54,206 DEBUG http-8080-1 annotation.InjectionMetadata:85 - Processing injected method of bean 'myController': AutowiredFieldElement for private es.unican.meteo.service.UserService es.unican.meteo.controller.MyController.userService
19:38:54,224 DEBUG http-8080-1 support.DefaultListableBeanFactory:217 - Creating shared instance of singleton bean 'userServiceImpl'
19:38:54,226 DEBUG http-8080-1 support.DefaultListableBeanFactory:430 - Creating instance of bean 'userServiceImpl'
19:38:54,234 DEBUG http-8080-1 annotation.InjectionMetadata:60 - Found injected element on class [es.unican.meteo.service.impl.UserServiceImpl]: AutowiredFieldElement for private es.unican.meteo.dao.UserMapper es.unican.meteo.service.impl.UserServiceImpl.userMapper
19:38:54,237 DEBUG http-8080-1 support.DefaultListableBeanFactory:504 - Eagerly caching bean 'userServiceImpl' to allow for resolving potential circular references
19:38:54,256 DEBUG http-8080-1 annotation.InjectionMetadata:85 - Processing injected method of bean 'userServiceImpl': AutowiredFieldElement for private es.unican.meteo.dao.UserMapper es.unican.meteo.service.impl.UserServiceImpl.userMapper
19:38:54,268  INFO http-8080-1 support.DefaultListableBeanFactory:433 - Destroying singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@56088b29: defining beans [myController,roleService,userServiceImpl,org.springframework.context.annotation.internalConfigurationAnnotationProcessor,org.springframework.context.annotation.internalAutowiredAnnotationProcessor,org.springframework.context.annotation.internalRequiredAnnotationProcessor,org.springframework.context.annotation.internalCommonAnnotationProcessor,org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping#0,org.springframework.format.support.FormattingConversionServiceFactoryBean#0,org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter#0,org.springframework.web.servlet.handler.MappedInterceptor#0,org.springframework.web.servlet.mvc.method.annotation.ExceptionHandlerExceptionResolver#0,org.springframework.web.servlet.mvc.annotation.ResponseStatusExceptionResolver#0,org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver#0,org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping,org.springframework.web.servlet.mvc.HttpRequestHandlerAdapter,org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter,org.springframework.web.servlet.view.InternalResourceViewResolver#0,org.springframework.context.annotation.ConfigurationClassPostProcessor$ImportAwareBeanPostProcessor#0]; root of factory hierarchy
19:38:54,279 ERROR http-8080-1 servlet.DispatcherServlet:457 - Context initialization failed

我已经回顾了一些关于这个主题的问题，但我没有找到解决问题的方法。也许我正在跳过一些东西，但我当然不知道。我尝试更改组件扫描没有结果。

I've reviewed some questions about this topic but i don't find a solution to my problem. Maybe i'm skipping something but i don't know certainly. I tried to change the component-scan with no results.

当我尝试访问/SPRING-MVC/getUsers.go时出现这些错误。

When i try to access to /SPRING-MVC/getUsers.go appears those errors.

我不知道bean是否必须放在app-config（applicationContext）或servlet.xml中，因为它有点令人困惑......

I don't know if the beans must be placed in app-config (applicationContext) or in the servlet.xml because it is a little bit confusing...

谢谢

推荐答案

你的配置很奇怪......

Your configuration is very strange...

我在 web.xml中看不到根Web应用程序上下文配置。可能是你忘了添加这段代码吗？

I don't see root web application context configuration in your web.xml. Could it be that you forgot to add this piece of code?

<context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>
        WEB-INF/app-config.xml
    </param-value>
</context-param>

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



现在有点理论



Spring的理论 - Spring使用Web应用程序的应用程序上下文层次结构：

Now a little bit of theory

Bit of Spring theory - Spring uses application context hierarchy for web applications:


  • 顶级Web应用程序上下文由加载ContextLoaderListener

  • 然后每个 DispatcherServlet 实例都有单独的上下文

  • top level web application context is loaded by ContextLoaderListener
  • then there are separate contexts for each DispatcherServlet instances

当实例化新bean时，它可以从定义它的上下文或从父上下文获取依赖项。这使得在根上下文（服务，DAO，...）中定义公共bean并在servlet应用程序上下文中具有请求处理bean成为可能，因为每个servlet都可以拥有自己的一组控制器，查看handers，...

When a new bean is being instantiated, it can get dependencies either from the context where it is being defined or from parent context. This makes possible to define common beans in the root context (services, DAO, ...) and have the request handling beans in servlet application contexts as each servlet can have its own set of controllers, view handers, ...

您正在根上下文中配置MVC。那是错的。从那里删除< mvc：上下文。

You are configuring MVC in your root context. That is just wrong. Remove the <mvc: context from there.

您还通过以下方式在根上下文中注册控制器您的基础包上的< context：component-scan> 。使组件只扫描服务包或将您的类分成两个顶级包 core （对于根bean） ）和 servlet （对于servlet bean）。

You are also registering your controllers in the root context via the <context:component-scan> on your base package. Make the component scan just on the services package or separate your classes into two top level packages core (for the root beans) and servlet (for servlet beans).

这篇关于Spring Autowiring Service在我的Controller中不起作用的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！

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