Java Server Pages

Jetty supports JSP via the ee{8,9,10}-jsp modules, which are based on Apache Jasper:

# DO NOT EDIT THIS FILE - See: https://eclipse.dev/jetty/documentation/

[description]
Enables JSP for all web applications deployed on the server.

[environment]
ee10

[depend]
ee10-servlet
ee10-annotations
ee10-apache-jsp

Logging has been bridged to Jetty logging, so you can enable logging for the org.apache.jasper package, subpackages and classes as usual.

Configuration of the JSP Servlet

The org.eclipse.jetty.jsp.JettyJspServlet is the servlet responsible for serving JSPs.

It is configured as the default jsp servlet in the $JETTY_HOME/etc/webdefault.xml file. Notice that Jetty identifies the jsp servlet by the presence of the id="jsp" attribute in the <servlet> declaration.

That file maps the org.eclipse.jetty.jsp.JettyJspServlet to the following partial urls:

  • *.jsp

  • *.jspf

  • *.jspx

  • *.xsp

  • *.JSP

  • *.JSPF

  • *.JSPX

  • *.XSP

You can change to a different servlet, change or add <init-param>s or add extra <servlet-mapping>s in your web.xml file.

Here’s an example of adding an <init-param> to augment the definitions from the standard webdefault.xml file:

<servlet id="jsp">  (1)
  <servlet-name>jsp</servlet-name> (2)
  <init-param>
    <param-name>keepgenerated</param-name> (3)
    <param-value>true</param-value>  (4)
  </init-param>
</servlet>
1 This identifies this servlet as the jsp servlet to Jetty.
2 This identifies this declaration as augmenting the already-defined servlet called jsp.
3 This init param controls whether the jsp servlet retains the *.java files generated during jsp compilation.
4 This sets the value of the init param

Another element you might consider adding to the default setup is async-supported:

<servlet id="jsp">  (1)
  <servlet-name>jsp</servlet-name>  (2)
  <async-supported>true</async-supported>  (3)
</servlet>
1 This identifies this servlet as the jsp servlet to Jetty.
2 This identifies this declaration as augmenting the already-defined servlet called jsp.
3 By default, the jsp servlet does not support async.

There are many configuration parameters for the Apache Jasper JSP Servlet, here are some of them:

Table 1. JSP Servlet Parameters
init param Description Default webdefault.xml

checkInterval

If non-zero and development is false, background jsp recompilation is enabled. This value is the interval in seconds between background recompile checks.

0

–

classpath

The classpath is dynamically generated if the context has a URL classloader. The org.apache.catalina.jsp_classpath context attribute is used to add to the classpath, but if this is not set, this classpath configuration item is added to the classpath instead.`

-

–

classdebuginfo

Include debugging info in class file.

true

–

compilerClassName

If not set, defaults to the Eclipse jdt compiler.

-

–

compiler

Used if the Eclipse jdt compiler cannot be found on the classpath. It is the classname of a compiler that Ant should invoke.

–

–

compilerTargetVM

Target vm to compile for.

1.8

1.8

compilerSourceVM

Sets source compliance level for the jdt compiler.

1.8

1.8

development

If true recompilation checks occur at the frequency governed by modificationTestInterval.

true

–

displaySourceFragment

Should a source fragment be included in exception messages

true

–

dumpSmap

Dump SMAP JSR45 info to a file.

false

–

enablePooling

Determines whether tag handler pooling is enabled.

true

–

engineOptionsClass

Allows specifying the Options class used to configure Jasper. If not present, the default EmbeddedServletOptions will be used.

-

–

errorOnUseBeanInvalidClassAttribute

Should Jasper issue an error when the value of the class attribute in an useBean action is not a valid bean class

true

–

fork

Only relevant if you use Ant to compile JSPs: by default Jetty will use the Eclipse jdt compiler.

true

-

genStrAsCharArray

Option for generating Strings as char arrays.

false

–

ieClassId

The class-id value to be sent to Internet Explorer when using <jsp:plugin> tags.

clsid:8AD9C840-044E-11D1-B3E9-00805F499D93

–

javaEncoding

Pass through the encoding to use for the compilation.

UTF8

–

jspIdleTimeout

The amount of time in seconds a JSP can be idle before it is unloaded. A value of zero or less indicates never unload.

-1

–

keepgenerated

Do you want to keep the generated Java files around?

true

–

mappedFile

Support for mapped Files. Generates a servlet that has a print statement per line of the JSP file

true

–

maxLoadedJsps

The maximum number of JSPs that will be loaded for a web application. If more than this number of JSPs are loaded, the least recently used JSPs will be unloaded so that the number of JSPs loaded at any one time does not exceed this limit. A value of zero or less indicates no limit.

-1

–

modificationTestInterval

If development=true, interval between recompilation checks, triggered by a request.

4

–

quoteAttributeEL

When EL is used in an attribute value on a JSP page, should the rules for quoting of attributes described in JSP.1.6 be applied to the expression

true

-

recompileOnFail

If a JSP compilation fails should the modificationTestInterval be ignored and the next access trigger a re-compilation attempt? Used in development mode only and is disabled by default as compilation may be expensive and could lead to excessive resource usage.

false

–

scratchDir

Directory where servlets are generated. The default is the value of the context attribute javax.servlet.context.tempdir, or the system property java.io.tmpdir if the context attribute is not set.

–

–

strictQuoteEscaping

Should the quote escaping required by section JSP.1.6 of the JSP specification be applied to scriplet expression.

true

-

suppressSmap

Generation of SMAP info for JSR45 debugging.

false

–

trimSpaces

Should template text that consists entirely of whitespace be removed from the output (true), replaced with a single space (single) or left unchanged (false)? Note that if a JSP page or tag file specifies a trimDirectiveWhitespaces value of true, that will take precedence over this configuration setting for that page/tag. trimmed?

false

–

xpoweredBy

Generate an X-Powered-By response header.

false

false

If the value you set doesn’t take effect, try using all lower case instead of camel case, or capitalizing only some of the words in the name, as Jasper is inconsistent in its parameter naming strategy.