Skip to end of metadata
Go to start of metadata

You are viewing an old version of this page. View the current version.

Compare with Current View Page History

« Previous Version 11 Next »

You can write normal Java servlets in Groovy (i.e. Groovlets).
There is also a GroovyServlet which automatically compile your .groovy source files, turn them into bytecode, load the Class and cache it until you change the source file.

Here's a simple example to show you the kind of thing you can do from a Groovlet.
Notice the use of implicit variables to access the session, output & request.

Or, do the same thing using MarkupBuilder:

Implicit variables

The following variables are ready for use in Groovlets:

variable name

bound to

note

request

ServletRequest

-

response

ServletResponse

-

context

ServletContext

unlike Struts

application

ServletContext

unlike Struts

session

getSession(false)

can be null! see (star) A

out

response.getWriter()

see (star) B

sout

response.getOutputStream()

see (star) B

html

new MarkupBuilder(out)

see (star) B

(star) A The session variable is only set, if there was already a session object. See the 'if (session == null)' checks in
the examples above.

(star) B These variables cannot be re-assigned inside a Groovlet. They are bound on first access, allowing to e.g. calling methods on the 'response' object before using 'out'.

Setting up groovylets

Put the following in your web.xml:

Then all the groovy jar files into WEB-INF/lib. You should only need to put the groovy.jar, the antlr.jar and the asm.jar. Or copy the groovy-all-xyz.jar into WEB-INF/lib - this almost all jar contains the antlr and asm jars.

Now put the .groovy files in, say, the root directory (i.e. where you would put your html files). The groovy servlet takes care of compiling the .groovy files.

So for example using tomcat you could edit tomcat/conf/server.xml like so:

Then access it with http://localhost:8080/groovy/hello.groovy

  • No labels