java - 这些 url 映射模式有什么区别？

Question

这些 url 映射之间有什么区别？

<url-pattern>/servlet</url-pattern>

和

<url-pattern>/servlet/*</url-pattern>

和

<url-pattern>/*</url-pattern>

和

 <url-pattern>*.do</url-pattern>

Answer 1

URL 模式在 Servlet 3.0 Specification 中进行了解释。 ，第 12.2 映射规范:

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/<context-root>/. 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.