-          url pattern of a servlet is very much useful to hide servlet class name from the end user of web application to generate register to servlet web resource program from browser window
-          according to sun Microsystems there are three types of url pattern programmer can chose any one types of url pattern while providing url pattern to the servlet
-          while giving request to servlet web resources program the end user must know url pattern of the servlet
-          3 types of url pattern
o        Exact match
§         In this style of url pattern multiple words can be there separate with slash ‘/’ symbol, but the symbol star ‘*’ must not appears in the url pattern
<servlet>
<servlet-name> ABC</servlet-name>
<servlet –class> DateSrv</servlet-class>
<servlet-mapping >
<servlet-name> ABC</servlet-name>
<Url-pattern> /test/xyz</url-pattern>
</servlet-mapping >
§         Example url: from browser window
·         http://localhost:2020/DateApp/test/xyz(valid)
·         http://localhost:2020/DateApp/xyz/test(in valid)
·         http://localhost:2020/DateApp/xyz(in valid)
§         Other exact match url pattern example
·         <url-pattern>/test</url-pattern>
·         <url-pattern>/test/xyz./abc</url-pattern>
·         <url-pattern>/ab/xyz/123</url-pattern>
·         <url-pattern>/a</url-pattern>
·         <url-pattern>/abv/xyz.test.c</url-pattern>
§         By taking the support of those sensible url pattern we can hide the technology name of servlet web resource from end user of web application
o        Directory match
§         Contain * symbol at the end of the url pattern words and url pattern can contain one / more words in it
§         Example : <url-pattern>/x/y/*</url-pattern>, in this example x, y are directory and * symbol must be write
§         * symbol represents zero/ more char presence/ words presence
§         Example urls:
·         http://localhost:2020/DateApp/x/y/abc valid
·         http://localhost:2020/DateApp/x/y/xyz/abc valid
·         http://localhost:2020/DateApp/x/y x/y valid
·         http://localhost:2020/DateApp/x/y- valid
·         http://localhost:2020/DateApp/x/z/abc in valid
·         http://localhost:2020/DateApp/a/b/x/y in valid
·         http://localhost:2020/DateApp/px/y/z/abc/xyz in valid

o        Extension match
§         in extension match url pattern the sybols * must be the first character of url pattern and the extension can be any word/letter
<url-pattern>*.xyz</url-pattern>


§         example urls:
·         http://localhost:2020/DateApp/abc.xyz valid
·         http://localhost:2020/DateApp/123.xyz valid
·         http://localhost:2020/DateApp/xyz/test/abcxyz valid

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