dispatchservlet url-pattern /* /区别

本文介绍了在使用SpringMVC时,web.xml中配置dispatchservlet时<url-pattern> / </url-pattern>和<url-pattern> /* </url-pattern>的区别。前者不会匹配*.jsp,后者会匹配所有URL,返回jsp视图时可能报404错。

在使用springmvc时,都会在web.xml中配置一个dispatchservlet,如下:

<listener>

<listener-class>

org.springframework.web.context.ContextLoaderListener

</listener-class>

</listener>

<!-- Spring MVC Servlet -->

<servlet>

<servlet-name>servletName</servlet-name>

<servlet-class>

org.springframework.web.servlet.DispatcherServlet

</servlet-class>

<load-on-startup>1</load-on-startup>

</servlet>

<servlet-mapping>

<servlet-name>servletName</servlet-name>

<strong><url-pattern>/</url-pattern></strong>

</servlet-mapping>

其中/和/*的区别:

< 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。 

总之,关于web.xml的url映射的小知识:

<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)

<?xml version="1.0" encoding="UTF-8"?> <web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"> <display-name>spring</display-name> <!-- 加载Spring配置文件 --> <context-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:spring/spring.xml</param-value> </context-param> <!-- 字符集 过滤器 --> <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> </filter> <filter-mapping> <filter-name>encodingFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> <!-- Spring监听器 --> <listener> <description>Spring监听器</description> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener> <!-- 防止Spring内存溢出监听器 --> <listener> <listener-class>org.springframework.web.util.IntrospectorCleanupListener</listener-class> </listener> <!-- Spring MVC --> <servlet> <servlet-name>SpringMVC</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <init-param> <description>SpringMVC</description> <param-name>contextConfigLocation</param-name> <param-value>classpath:spring/spring-mvc.xml</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <!-- 本次需要做的配置,注意位置,要放在配置springmvc的url-pattern之前 --> <!-- 表示当程序加载符合这些路径的资源时,不会通过dispatchservlet --> <servlet-mapping> <servlet-name>default</servlet-name> <url-pattern>*.js</url-pattern> <url-pattern>*.css</url-pattern> <url-pattern>*.html</url-pattern> <url-pattern>/upload/*</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>SpringMVC</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> <!-- Session超时时间 --> <!-- <session-config> <session-timeout>15</session-timeout> </session-config> --> </web-app>
06-14
package moon.sun; import java.io.IOException; import java.io.PrintWriter; import java.util.regex.Matcher; import java.util.regex.Pattern; import javax.servlet.ServletConfig; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; /** * Servlet implementation class Example6_3_Servlet */ @WebServlet("/Example6_3_Servlet") public class Example6_3_Servlet extends HttpServlet { public void init(ServletConfig config) throws ServletException { super.init(config); // TODO Auto-generated constructor stub } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */ public void service(HttpServletRequest request, HttpServletResponse response) throws IOException { request.setCharacterEncoding("utf-8"); response.setContentType("text/html;charset = utf-8"); PrintWriter out = response.getWriter();//获得向用户发送数据的输出流 out.println("<html><body bgcolor = yellow"); String discountMess = request.getParameter("discount"); double discount = Double.parseDouble(discountMess); String billMess = request.getParameter("billMess"); if(billMess == null) { out.print("没有账单"); return; } double bill = getPriceSum(billMess);//账单金额 double billDiscount = bill * (discount/10);//优惠后的金额 out.println("<h2>" + billMess + "<br>消费:" + bill + "元"); out.println("优惠" + discount + "折<br>后的金额:" + billDiscount + "元"); out.println("<br>王佳慧 251053011408"); out.println("</h2></body></html>"); } public double getPriceSum(String input) { Pattern pattern; Matcher matcher; String regex = "-?[0-9]*[.]?[0-9]*"; pattern =Pattern.compile(regex); matcher = pattern.matcher(input); double sum = 0; while(matcher.find()) { String str = matcher.group(); sum += Double.parseDouble(str); } return sum; } }
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