Question

使用注释组件扫描标记时，MVC应用程序抛出404错误。使用显式xml bean注入也可以正常工作。请在下面找到相应的代码。

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" 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>AbsSpringMVCProj</display-name>

  <servlet>
    <servlet-name>spring-dispatcher</servlet-name>
    <servlet-class>
    org.springframework.web.servlet.DispatcherServlet
    </servlet-class>
    </servlet>
    <servlet-mapping>

    <servlet-name>spring-dispatcher</servlet-name>
    <url-pattern>/</url-pattern>
    </servlet-mapping>


</web-app>

弹簧调度-servlet.xml中

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xmlns:context="http://www.springframework.org/schema/context" 
    xsi:schemaLocation="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/mvc
        http://www.springframework.org/schema/mvc/spring-mvc.xsd">

<mvc:annotation-driven />
    <context:component-scan base-package="com.happy.hellocontroller.HelloController" />
 <!-- <bean id="HandlerMapping"  class="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping"/>  -->

    <!-- <context:component-scan base-package = "com.happy.hellocontroller.HelloController" /> -->

    <!-- <bean name="/welcome.html" class="com.happy.hellocontroller.HelloController" /> -->
   <!-- <bean name="/page2.html" class="com.happy.hellocontroller.HelloController" />
   <bean name="/greet/page2.html" class="com.happy.hellocontroller.HelloController" />   -->

 <bean id="viewResolver"
        class="org.springframework.web.servlet.view.InternalResourceViewResolver" >
        <property name="prefix">
            <value>/WEB-INF/</value>
        </property>
        <property name="suffix">
            <value>.jsp</value>
        </property>
 </bean>


</beans>

HelloController.java

package com.happy.hellocontroller;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.AbstractController;


/*
 * XML based
 * 
 *//*
public class HelloController extends AbstractController{

    @Override
    protected ModelAndView handleRequestInternal(HttpServletRequest request,
            HttpServletResponse response) throws Exception {
        // TODO Auto-generated method stub
        ModelAndView modelandView = new ModelAndView("HelloPage");
        modelandView.addObject("welcomeMsg","Hi, this is coming from HelloController class");


        return modelandView;
    }

}*/

/*
 * Annotation base
 * 
 *  
 */
@Controller
public class HelloController {

    @RequestMapping("/welcome")
    public ModelAndView helloAbs()
    {
        ModelAndView modelandView = new ModelAndView("HelloPage");
         modelandView.addObject("welcomeMsg","Annotation Based, this is coming from HelloController class");

         return modelandView;
    }
    @RequestMapping("/page2")
    public ModelAndView helloPage2()
    {
        ModelAndView modelandView = new ModelAndView("HelloPage");
         modelandView.addObject("welcomeMsg","Annotation Based, this is coming from HelloController-helloPage2 class");

         return modelandView;
    }
    @RequestMapping("/page3")
    public ModelAndView helloPage3()
    {
        ModelAndView modelandView = new ModelAndView("HelloPage");
         modelandView.addObject("welcomeMsg","Annotation Based, this is coming from HelloController-helloPage33 class");

         return modelandView;
    }

}

当尝试点击网址“http://localhost:8080/AbsSpringMVCProj/welcome.html”时，它说

HTTP 404，找不到资源。

当 spring-dispatcher-servlet.xml 中的以下块取消注释时，同样正常工作： -

<!-- <bean  id="HandlerMapping"  class="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping"/>  -->

    <!-- <context:component-scan base-package = "com.happy.hellocontroller.HelloController" /> -->

    <!-- <bean name="/welcome.html" class="com.happy.hellocontroller.HelloController" /> -->
   <!-- <bean name="/page2.html" class="com.happy.hellocontroller.HelloController" />
   <bean name="/greet/page2.html" class="com.happy.hellocontroller.HelloController" />   -->

请帮助我理解：

使用注释时我可能做错了什么？
我是否缺少使组件扫描标签工作的设置并自动获取@component和@RequetMapping标签？

Answer 1

您不需要在<context:component-scan ..>中声明特定的类名。只需要声明包级别。根据您的 spring-dispatcher-servlet.xml ，无需声明 HelloController 类。更改您的组件扫描标签

<context:component-scan base-package = "com.happy.hellocontroller" />

使用<context：component-scan>并抛出404错误时，spring MVC应用程序无法正常工作

1 个答案: