java - 向旧版 Spring 应用程序添加了组件扫描

Question

我有一个遗留的 Spring 应用程序，无论上下文是否完全使用 XML 配置。我想使用 @Controller 注释向应用程序添加一个新 Controller ，以便我开始迁移到使用注释。

作为测试，我已将以下 Controller 添加到应用程序

package uk.co.onevisionconsulting.engineermanager.webapp.controller2;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class HelloController {

     @RequestMapping("/hello")
     public String hello(){
          return "Hello";
     }
}

我还在我的 spring 上下文中添加了 context:component-scan 标签

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans” xmlns:context="http://www.springframework.org/schema/context"
             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-3.2.xsd
             http://www.springframework.org/schema/context
             http://www.springframework.org/schema/context/spring-context-2.5.xsd">

     <context:component-scan base-package="uk.co.onevisionconsulting.engineermanager" />

     <bean name="jsonView"
          class="uk.co.onevisionconsulting.engineermanager.webapp.view.JsonView" />

     <bean name="csvView"
          class="uk.co.onevisionconsulting.engineermanager.webapp.view.CsvView" />

     <bean name="ajaxView"
          class="uk.co.onevisionconsulting.engineermanager.webapp.view.AjaxView" />

     <bean name="dataTablesView"
          class="uk.co.onevisionconsulting.engineermanager.webapp.view.DataTablesView" />

     <bean id="exceptionResolver"
          class="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver">
          <property name="exceptionMappings">
               <props>
                    <prop key="org.springframework.dao.DataAccessException">
                         dataAccessFailure
                    </prop>
               </props>
          </property>
     </bean>

     <bean id=“someController"
          class="uk.co.onevisionconsulting.engineermanager.webapp.controller.SomeController" >
          <property name=“someManager" ref=“someManager" />
     </bean>

     <!-- Loads more controllers -->

     <bean id="multipartResolver"
          class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
          <property name="maxUploadSize" value="2097152" />
     </bean>

     <bean id="messageSource"
          class="org.springframework.context.support.ResourceBundleMessageSource">
          <property name="basename" value="ApplicationResources" />
          <property name="useCodeAsDefaultMessage" value="true" />
     </bean>

     <bean id="urlMapping"
          class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">
          <property name="mappings">
               <value>
                    <!— Some URLs —>
               </value>
          </property>
          <property name="order" value="0" />
     </bean>

     <bean
          class="org.springframework.web.servlet.mvc.support.ControllerClassNameHandlerMapping">
          <property name="order" value="1" />
     </bean>

     <bean class="org.springframework.web.servlet.view.BeanNameViewResolver">
          <property name="order" value="2" />
     </bean>

     <!-- View Resolver for JSPs -->
     <bean id="viewResolver"
          class="org.springframework.web.servlet.view.InternalResourceViewResolver">
          <property name="requestContextAttribute" value="rc" />
          <property name="viewClass"
               value="org.springframework.web.servlet.view.JstlView" />
          <property name="prefix" value="/WEB-INF/pages/" />
          <property name="suffix" value=".jsp" />
     </bean>
</beans>

尽管类路径扫描器 (ClassPathScanningCandidateComponentProvider) 拾取了 HelloController，但当我尝试导航到 localhost:8080/hello 时，我得到了 404

谁能看到我还需要做什么？这是我的 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_2_5.xsd"
    id="WebApp_ID" version="2.5">

    <display-name>Engineer Manager</display-name>

    <!-- Define the default CSS Theme -->
    <context-param>
        <param-name>csstheme</param-name>
        <param-value>engineermanager</param-value>
    </context-param>

    <!-- Define the basename for a resource bundle for I18N -->
    <context-param>
        <param-name>javax.servlet.jsp.jstl.fmt.localizationContext</param-name>
        <param-value>ApplicationResources</param-value>
    </context-param>

    <!-- Fallback locale if no bundles found for browser's preferred locale -->
    <!-- Force a single locale using param-name 'javax.servlet.jsp.jstl.fmt.locale' -->
    <context-param>
        <param-name>javax.servlet.jsp.jstl.fmt.fallbackLocale</param-name>
        <param-value>en</param-value>
    </context-param>

    <!-- Context Configuration locations for Spring XML files -->
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>
            classpath:/applicationContext-resources.xml
            classpath:/applicationContext-dao.xml
            classpath:/applicationContext-service.xml
            classpath*:/applicationContext.xml
            /WEB-INF/applicationContext*.xml
            /WEB-INF/security.xml
        </param-value>
    </context-param>

    <filter>
        <filter-name>localeFilter</filter-name>
        <filter-class>org.appfuse.webapp.filter.LocaleFilter</filter-class>
    </filter>
    <filter>
        <filter-name>securityFilter</filter-name>
        <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
        <init-param>
            <param-name>targetBeanName</param-name>
            <param-value>springSecurityFilterChain</param-value>
        </init-param>
    </filter>
    <filter>
        <filter-name>sitemesh</filter-name>
        <filter-class>com.opensymphony.module.sitemesh.filter.PageFilter</filter-class>
    </filter>
    <filter>
        <filter-name>staticFilter</filter-name>
        <filter-class>org.appfuse.webapp.filter.StaticFilter</filter-class>
        <init-param>
            <param-name>servletName</param-name>
            <param-value>dispatcher</param-value>
        </init-param>
    </filter>

    <filter-mapping>
        <filter-name>securityFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
    <filter-mapping>
        <filter-name>localeFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
    <filter-mapping>
        <filter-name>sitemesh</filter-name>
        <url-pattern>*.html</url-pattern>
        <dispatcher>REQUEST</dispatcher>
        <dispatcher>FORWARD</dispatcher>
    </filter-mapping>
    <filter-mapping>
        <filter-name>sitemesh</filter-name>
        <url-pattern>*.jsp</url-pattern>
        <dispatcher>REQUEST</dispatcher>
        <dispatcher>FORWARD</dispatcher>
    </filter-mapping>
    <filter-mapping>
        <filter-name>staticFilter</filter-name>
        <url-pattern>*.html</url-pattern>
        <dispatcher>REQUEST</dispatcher>
        <dispatcher>FORWARD</dispatcher>
    </filter-mapping>

    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
    <listener>
        <listener-class>org.springframework.web.util.IntrospectorCleanupListener</listener-class>
    </listener>
    <listener>
        <listener-class>org.appfuse.webapp.listener.StartupListener</listener-class>
    </listener>
    <listener>
        <listener-class>org.appfuse.webapp.listener.UserCounterListener</listener-class>
    </listener>

    <servlet>
        <servlet-name>dispatcher</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <load-on-startup>2</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>dispatcher</servlet-name>
        <url-pattern>*.json</url-pattern>
    </servlet-mapping>

    <session-config>
        <session-timeout>3600</session-timeout>
    </session-config>

    <welcome-file-list>
        <welcome-file>index.jsp</welcome-file>
    </welcome-file-list>

    <error-page>
        <error-code>500</error-code>
        <location>/error.jsp</location>
    </error-page>
    <error-page>
        <error-code>400</error-code>
        <location>/index.jsp</location>
    </error-page>
    <error-page>
        <error-code>403</error-code>
        <location>/403.jsp</location>
    </error-page>
    <error-page>
        <error-code>404</error-code>
        <location>/404.jsp</location>
    </error-page>
</web-app>

Answer 1

既然您提到这是一个遗留应用程序，我相信它可以使用现有的配置。

此外，由于您正在尝试使用新 Controller 的注释进行迁移，因此这与注释处理有关。

您需要在 spring 上下文 xml 文件的根 beans 标记中添加下面提到的注释以及 mvc 命名空间配置。

<mvc:annotation-driven/>

配置的部分代码片段如下

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    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
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc.xsd"
         http://www.springframework.org/schema/context
         http://www.springframework.org/schema/context/spring-context-2.5.xsd">

    <context:component-scan base-package="uk.co.onevisionconsulting.engineermanager" />
    <mvc:annotation-driven/>

    ...

</beans>

详细原因可以参见Spring MVC: difference between <context:component-scan> and <annotation-driven /> tags?