java - web.xml 中的 url-pattern 问题

Question

我在web.xml中的过滤器映射如下:

  <filter>
    <filter-name>LoginCheckFilter</filter-name>
    <filter-class>com.tutorial.filter.LoginCheckFilter</filter-class>
  </filter>
  <filter-mapping>
    <filter-name>LoginCheckFilter</filter-name>
    <url-pattern>/admin*</url-pattern>
  </filter-mapping>

当我运行我的应用程序并点击 http://localhost:8080/admin 时，我的过滤器没有被执行。我无法理解为什么。

图案有没有问题。此外，如果我从模式中删除 '*'，则过滤器会在点击上面的 url 时执行。

需要这方面的帮助。谢谢。

Answer 1

规范(第 12.2 段)说明如下:

In the Web application deployment descriptor, the following syntax is used to define mappings:

• A string beginning with a ‘/’ character and ending with a ‘/*’ suffix is used for path mapping.

• A string beginning with a ‘*.’ prefix is used as an extension mapping.

• The empty string ("") is a special URL pattern that exactly maps to the application's context root, i.e., requests of the form http://host:port/<contextroot>/. In this case the path info is ’/’ and the servlet path and context path is empty string (““).

• A string containing only the ’/’ character indicates the "default" servlet of the application. In this case the servlet path is the request URI minus the context path and the path info is null.

• All other strings are used for exact matches only.

所以 *按字面意思理解，除非模式以 /* 结尾或以 *. 开头