Java Bean @Autowired 错误

Question

基于Java的配置

package com.mgroup.init;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Scope;

import com.mgorup.dao.EmployeeDao;
import com.mgroup.controller.EmployeeController;
import com.mgroup.services.EmployeeService;

@Configuration
public class MyConfig {

    @Bean
    @Scope("prototype")
    public EmployeeService employeeServiceBean()
    {
        //constructor injection on a class StoreService. well it was, nto it is autowire
        return new EmployeeService();//(storeDaoBean());
    }

    @Bean
    @Scope("prototype")
    public EmployeeDao employeeDaoBean()
    {
        return new EmployeeDao();
    }


}

Controller 类

package com.mgroup.controller;

import javax.annotation.Resource;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

import com.mgroup.pojo.Patron;
import com.mgroup.services.EmployeeService;

@Controller
public class EmployeeController {

    @Autowired
    EmployeeService employeeServiceBean;


     /* Loading Home Page */
    @RequestMapping("/Login.html")
    public String loadLoginPage() {
        return "Welcome";
    }

}

错误代码

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'employeeController': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.fdmgroup.services.EmployeeService com.fdmgroup.controller.EmployeeController.employeeServiceBean; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.fdmgroup.services.EmployeeService] 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.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:288)
    org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1116)
    org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:519)
    org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:458)
    org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:295)

我还有 EmployeeService 和 EmployeeDao。他们在 Autowiring 方面做得很好。即见下文。当我尝试在 Controller 类中使用 Autowiring 注释注入(inject) EmployeeService 时遇到的问题我收到上面的错误。是因为我有基于Java的配置类和具有Component-Scan的xml配置类吗？

@Service
public class EmployeeService implements EmployeeServicesInterface{

    @Autowired
    EmployeeDao employeeDaoBean;
    @Override

这是我的 servlet.xml。我删除了括号中的架构以保留一些空间。

<beans >

   <!-- Scan the package containing annotations -->     
  <context:annotation-config />
  <context:component-scan base-package="com.mgroup.controller" />

  <!-- jspViewResolver bean – This bean defined view resolver for spring mvc. For this bean we also set prefix as “/WEB-INF/jsp/”
   and suffix as “.jsp”. Thus spring automatically resolves the JSP from WEB-INF/jsp folder and assigned suffix .jsp to it. -->
  <bean id="jspViewResolver"
        class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="viewClass"
            value="org.springframework.web.servlet.view.JstlView" />
        <property name="prefix" value="/WEB-INF/views/" />
        <property name="suffix" value=".jsp" />
    </bean>

</beans>

这是 web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>library</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>

   <servlet>
        <servlet-name>spring</servlet-name>
        <servlet-class>
            org.springframework.web.servlet.DispatcherServlet
        </servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>spring</servlet-name>
        <url-pattern>*.html</url-pattern>
    </servlet-mapping>


</web-app>

Answer 1

您是否配置了用于配置应用程序的组件或 bean 的 @Configuration 类？

您可以在 web.xml 文件中尝试此操作来加载配置类。

<context-param>
        <param-name>contextClass</param-name>
        <param-value>org.springframework.web.context.support.AnnotationConfigWebApplicationContext</param-value>
</context-param>

<context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>com.mgroup.init</param-value>
</context-param>