url-pattern*.htmlurl-pattern導致根路徑訪問404的問題

背景：有一個spring mvc項目，web.xml的配置如下

<?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">


    <!-- The definition of the Root Spring Container shared by all Servlets and Filters -->
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <!--<param-value>classpath:META-INF/spring/spring-config.xml,classpath:META-INF/spring/spring-shiro.xml</param-value>-->
        <param-value>classpath:META-INF/spring/spring-config.xml</param-value>
    </context-param>

    <context-param>
        <param-name>webAppRootKey</param-name>
        <param-value>manage-web.all.root</param-value>
    </context-param>

    <context-param>
        <param-name>log4jConfigLocation</param-name>
        <param-value>classpath:logback.xml</param-value>
    </context-param>

    <!-- Processes application requests -->
    <servlet>
        <servlet-name>springMVC</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:META-INF/spring/springMVC-servlet.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>springMVC</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

   

    <filter>
        <filter-name>encodingFilter</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>UTF-8</param-value>
        </init-param>
        <init-param>
            <param-name>forceEncoding</param-name>
            <param-value>true</param-value>
        </init-param>
    </filter>

    <filter-mapping>
        <filter-name>encodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

    <!-- 設置超時時間-->
    <session-config>
        <session-timeout>30</session-timeout>
    </session-config>

    <error-page>
        <error-code>400</error-code>
        <location>/static/error.html</location>
    </error-page>
    <!-- 404 頁面不存在錯誤 -->
    <error-page>
        <error-code>404</error-code>
        <location>/static/error.html</location>
    </error-page>
    <!-- 500 服務器內部錯誤 -->
    <error-page>
        <error-code>500</error-code>
        <location>/static/error.html</location>
    </error-page>

    <error-page>
        <error-code>401</error-code>
        <location>/static/error_authorization.html</location>
    </error-page>

</web-app>

有一個controller是這樣的定義的

    @RequestMapping(value = {"/manage/main", "/"}, method = RequestMethod.GET)
    public ModelAndView index2() throws ServletException {
}

通過localhost:8080/可以訪問。

爲了能夠過濾html靜態文件，加了

    <servlet-mapping>
        <servlet-name>default</servlet-name>
        <url-pattern>*.html</url-pattern>
    </servlet-mapping>

之後再運行項目，訪問localhost:8080/，就報錯404了。

結論：

參考https://blog.csdn.net/shuair/article/details/86645707

請求根路徑（ip:port/項目名/，本項目部署再ROOT文件夾下面，不需要項目名） 時，如果我們自定義的servlet沒有配置“/*”前綴匹配，那麼請求路徑無法依據精確匹配、前綴匹配及擴展名匹配被任何servlet匹配到，此時會增加一個資源文件（welcomeResources）匹配方式，先拼接welcome-file的值再進行如上三種匹配。

本項目種一開始沒有配置<url-pattern>*.html</url-pattern>靜態資源，也沒有配置“/*”前綴匹配，在訪問localhost:8080/時，請求路徑無法依據精確匹配、前綴匹配及擴展名匹配被任何servlet匹配到，此時welcome-file的值再進行如上三種匹配，仍然沒有匹配到，進入<url-pattern>/</url-pattern>這個servlet執行。

後來增加了配置<url-pattern>*.html</url-pattern>靜態資源，訪問localhost:8080/時，請求路徑無法依據精確匹配、前綴匹配及擴展名匹配被任何servlet匹配到，此時welcome-file的值再進行如上三種匹配，比如說localhost:8080/index.html這個時候就後被<url-pattern>*.html</url-pattern>匹配到了。由於本項目種沒有index.html，因此報錯404