java - Spring MVC 没有检测到我的 Controller

Question

我有一个包含以下文件的 Spring MVC 项目:

/src/main/webapp/WEB-INF/web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app>
      <display-name>Archetype Created Web Application</display-name>
       <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/appconfig-root.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>

还有2个配置文件:

/src/main/webapp/WEB-INF/appconfig-root.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns="http://www.springframework.org/schema/beans"
       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.xsd">

    <import resource="appconfig-mvc.xml"/>

    <context:component-scan base-package="yc.servlets"/>

    <!--<context:property-placeholder location="classpath:application.properties"/>-->
</beans>

/src/main/webapp/WEB-INF/appconfig-mvc.xml

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

    <mvc:annotation-driven/>

    <mvc:resources mapping="/resources/**" location="/resources/"/>

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

        <property name="suffix">
            <value>.jsp</value>
        </property>
    </bean>
</beans>

以及包含我的 Controller 的类:

package yc.servlets;

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

@Controller
public class TestPage {


    @RequestMapping(value = "/hello_there", method = RequestMethod.GET)
    public String hello() {
        return "hello";
    }
}

我认为这足以让 spring mvc 正常工作，但是当我在浏览器中键入 localhost:8888 时，我收到了 404 错误。

localhost:8888/hello_there 也给出了 404 错误。

Answer 1

您好，您正在 Controller 中返回“hello”，它会找到 hello.jsp如果找不到它会抛出 404 http 错误

当您配置 InternalViewResolver 时:

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

        <property name="suffix">
            <value>.jsp</value>
        </property>
    </bean>

它试图在/WEB-INF/jsp/hello.jsp 中查找，所以当您在 Controller 中返回字符串“hello”时:

@RequestMapping(value = "/hello_there", method = RequestMethod.GET)
    public String hello() {
        return "hello";
    }

它会为“hello”添加一个后缀“.jsp”，它会尝试寻找“hello.jsp”，因为找不到它会抛出 404

您可以将您的@Controller 更改为@RestController，它隐含地添加@ResponseBody 注释并查看它是否在响应中返回“hello”

此外，如果这对您没有帮助，您可以更改:

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

到这个:

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

如果它现在仍然有效，请尝试下一步:

试试这样的网址:

localhost:8080/yourApplicationName/hello_there

默认 conext-path 在这里是你的应用程序名称如果你去 TOMCAT_HOME/webapps/

你会发现根目录下没有你的应用

这就是为什么 localhost:8080/... 找不到它的原因

您可以通过两种方式解决此问题:

1.Find your application deployed and copy to root folder in 
    TOMCAT_HOME/webapps/ROOT
 2.See the name of your application in  TOMCAT_HOME/webapps/ 
   and call url : localhost:8080/yourAppName/hello_world   

谢谢