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You can write normal Java servlets in Groovy (i.e. Groovlets).
There is also a GroovyServlet

which This feature will 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. Also notice that this is more like a script as it doesn't have a class wrapper.

Code Block
java
java
if (!session) {
  session = request.getSession(true);
}

if (!session.counter) {
  session.counter = 1
}

println """
<html>
    <head>
        <title>Groovy Servlet</title>
    </head>
    <body>
Hello, ${request.remoteHost}: ${session.counter}! ${new Date()}
    </body>
</html>
"""
session.counter = session.counter + 1



Or, do the same thing using MarkupBuilder:

Code Block
java
java
if (!session) {
  session = request.getSession(true)
}

if (!session.counter) {
      session.counter = 1
}

html.html {    // html is implicitly bound to new MarkupBuilder(out)
  head {
      title("Groovy Servlet")
  }
  body {
    p("Hello, ${request.remoteHost}: ${session.counter}! ${new Date()}")
  }
}
session.counter = session.counter + 1

...

Put the following in your web.xml:

Code Block
xml
xml
<servlet>
<servlet-name>Groovy</servlet-name>
<servlet-class>groovy.servlet.GroovyServlet</servlet-class>
</servlet>

<servlet-mapping>
<servlet-name>Groovy</servlet-name>
<url-pattern>*.groovy</url-pattern>
</servlet-mapping>



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:

Code Block
xml
xml
<Context path="/groovy" docBase="c:/groovy-servlet"/>



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