java - HTTP 请求未委托(delegate)给根 WebApplicationContext 的 Controller

Question

我正在关注这个Spring Docs并配置 web.xml 和 applicatioinContext.xml 以使用特性 Spring Web MVC 中的单根上下文 即有没有 Servlet WebApplicationContext；所有请求都将由 Root WebApplicatioinContext 提供。

但问题是 HTTP 请求没有被委托(delegate)给根 WebApplicationContext 的 Controller 。

web.xml:

<web-app>
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/root-context.xml</param-value>
    </context-param>
    <servlet>
        <servlet-name>dispatcher</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value></param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>dispatcher</servlet-name>
        <url-pattern>/*</url-pattern>
    </servlet-mapping>
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
</web-app>

root-context.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"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="PostController" class="org.my.controllers.PostController">
    </bean>

</beans>

Controller :

@Controller
public class PostController {
    @RequestMapping(value= "/controller", method = RequestMethod.GET)
    @ResponseBody
    public String foo() {
        return "Response!";
    }
}

所以当我点击 URL http://localhost:8080/PracticeJavaWeb/controller在浏览器中显示 404

服务器日志说:

WARNING: No mapping found for HTTP request with URI [/PracticeJavaWeb/controller] in DispatcherServlet with name 'dispatcher'

Spring Docs说:

It is also possible to have just one root context for single DispatcherServlet scenarios.

Answer 1

只需对 root-context.xml 文件进行一点小改动，添加:

<mvc:annotation-driven></mvc:annotation-driven>

mvc:annotation-driven 使上下文路径能够识别 spring mvc 注释，以便将请求分派(dispatch)给 Controller 。

这里还有一个 root-context.xml 的完整示例

<?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/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.3.xsd
        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-4.3.xsd">


    <mvc:annotation-driven></mvc:annotation-driven>

    <bean id="welcomeService" class="com.myorg.controller.MyService"></bean>
    <bean id="welcomControler" class="com.myorg.controller.WelcomeController"></bean>
    <bean id="viewResolver"
        class="org.springframework.web.servlet.view.InternalResourceViewResolver">
    <property name="prefix" value="/WEB-INF/views/"></property>
    <property name="suffix" value=".jsp"></property>
    </bean>

</beans>