JavaServer Pages, Second Edition

Name

<servlet-mapping>

Synopsis

Most containers support a special URI prefix (/servlet) that can invoke any servlet class the container has access to, for instance the URI /servlet/com.mycompany.MyServlet can be invoke the servlet class com.mycomapany.MyServlet. This isn’t mandated by the specification, however, so to make sure the application is portable, it’s better to map a unique path to a servlet instead. Explicit mapping also simplifies references between servlets and JSP pages, as described in Chapter 18. The <servlet-mapping> element is used for this purpose. The <servlet-name> subelement contains a name defined by a <servlet> element, and the <url-pattern> contains the pattern that should be mapped to the servlet (or JSP page):

<servlet-mapping>
  <servlet-name>purchase</servlet-name>
  <url-pattern>/po/*</url-pattern>
</servlet-mapping>
  
<servlet-mapping>
  <servlet-name>sales-report</servlet-name>
  <url-pattern>/report</url-pattern>
</servlet-mapping>
  
<servlet-mapping>
  <servlet-name>XMLProcessor</servlet-name>
  <url-pattern>*.xml</url-pattern>
</servlet-mapping>

A pattern can take one of four forms:

• A path prefix pattern starts with a slash (/) and ends with /*, for instance /po/*.

• An extension mapping pattern starts with *., for instance *.xml.

• A default servlet pattern consists of just the / character.

• All other patterns are exact match patterns.

When the container receives a request, it strips off the context path and then tries to find a pattern that matches a servlet mapping. ...