< url-pattern>/</url-pattern> 会匹配到/login这样的路径型url，不会匹配到模式为*.jsp这样的后缀型url
< url-pattern>/*</url-pattern> 会匹配所有url：路径型的和后缀型的url(包括/login,*.jsp,*.js和*.html等)
因为 springmvc 要使用DispatcherServlet类 处理 前端的 请求，所以配置为< url-pattern > / </ url-pattern > 将路径型url 交给springMVC处理
例如 中文乱码处理、shiro 安全认证处理需要处理所有的 url ，所以配置为< url-pattern > /* </ url-pattern >
< url-pattern > / </ url-pattern > 不会匹配到*.jsp，即：*.jsp不会进入spring的 DispatcherServlet类 。
< url-pattern > /* </ url-pattern > 会匹配*.jsp，会出现返回jsp视图时再次进入spring的DispatcherServlet 类，导致找不到对应的controller所以报404错。
例某 web.xml文件配置：
1 <?xml version="1.0" encoding="UTF-8"?> 2 <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"> 3 <!-- 配置spring 上下文参数 --> 4 <context-param> 5 <param-name>contextConfigLocation</param-name> 6 <param-value>classpath:applicationContext.xml</param-value> 7 </context-param> 8 <!-- 配置spring ---- 配置侦听器 --> 9 <listener> 10 <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> 11 </listener> 12 <!-- 配置springmvc 核心控制器 --> 13 <servlet> 14 <servlet-name>springDispatcherServlet</servlet-name> 15 <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> 16 <init-param> 17 <param-name>contextConfigLocation</param-name> 18 <param-value>classpath:springMVC.xml</param-value> 19 </init-param> 20 <load-on-startup>1</load-on-startup> 21 </servlet> 22 <servlet-mapping> 23 <servlet-name>springDispatcherServlet</servlet-name> 24 <url-pattern>/</url-pattern> 25 </servlet-mapping> 26 <!-- 配置shiro认证过滤器 --> 27 <filter> 28 <filter-name>shiroFilter</filter-name> 29 <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class> 30 <init-param> 31 <param-name>targetFilterLifecycle</param-name> 32 <param-value>true</param-value> 33 </init-param> 34 </filter> 35 <filter-mapping> 36 <filter-name>shiroFilter</filter-name> 37 <url-pattern>/*</url-pattern> 38 </filter-mapping> 39 <!-- 配置编码过滤器（只对post方法） --> 40 <filter> 41 <filter-name>CharacterEncodingFilter</filter-name> 42 <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class> 43 <init-param> 44 <param-name>encoding</param-name> 45 <param-value>UTF-8</param-value> 46 </init-param> 47 <init-param> 48 <param-name>forceRequestEncoding</param-name> 49 <param-value>true</param-value> 50 </init-param> 51 <init-param> 52 <param-name>forceResponseEncoding</param-name> 53 <param-value>true</param-value> 54 </init-param> 55 </filter> 56 <filter-mapping> 57 <filter-name>CharacterEncodingFilter</filter-name> 58 <url-pattern>/*</url-pattern> 59 </filter-mapping> 60 </web-app>