Add jsp-support to embedded Jetty 12

Question

I am trying to make an application with an embedded Jetty 12.0.7 that should serve static content like html and css files and dynamic like servlets and filters. The code I have, so far, goes here:

    public static void init() throws Exception {
        Server server = new Server();

        ServerConnector connector = new ServerConnector(server);
        connector.setPort(8080);
        server.addConnector(connector);

        // Create and configure a ResourceHandler.
        WebAppContext handler = new WebAppContext();

        // Configure the directory where static resources are located.
        URL r = Start.class.getResource("/web/");
        System.out.println(r);
        handler.setBaseResource(ResourceFactory.of(handler).newResource(r));

        server.setHandler(handler);
        handler.addServlet(HelloServlet.class, "/hi");
        handler.addFilter(LoggerFilter.class, "/*",
                EnumSet.of(INCLUDE, ASYNC, FORWARD, ERROR, REQUEST));

        server.start();
    }

Now I want to add support to also have jsp files along with the other stuff under /web/ (which, by the way, is under the /src/main/resources/ path). Does anyone know how to add jsp support to the function above? My dependencies, so far, look like this:

    <properties>
        <maven.compiler.source>21</maven.compiler.source>
        <maven.compiler.target>21</maven.compiler.target>
        <jetty.version>12.0.7</jetty.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.eclipse.jetty.ee10</groupId>
            <artifactId>jetty-ee10-webapp</artifactId>
            <version>${jetty.version}</version>
        </dependency>

        <dependency>
            <groupId>org.eclipse.jetty</groupId>
            <artifactId>jetty-server</artifactId>
            <version>${jetty.version}</version>
        </dependency>

        <dependency>
            <groupId>org.eclipse.jetty.ee10</groupId>
            <artifactId>jetty-ee10-apache-jsp</artifactId>
            <version>${jetty.version}</version>
        </dependency>
    </dependencies>

I have been trying to make Jetty 'understand' jsp-files but to no success.

Answer 1

I'm not using WebAppContext but ServletContextHandler, but hopefully it won't be much different.

First, JettyJasperInitializer has to be added in addition to JettyJspServlet:

handler.addServletContainerInitializer(JettyJasperInitializer.class);
handler.addServlet(JettyJspServlet.class, "*.jsp");

But that's not enough actually, you also have to explicitly set the handler's class loader:

handler.setClassLoader(Thread.currentThread().getContextClassLoader());

(you could also use Start.class.getClassLoader())

I do also set a specific temporary directory, although it's not required:

var tempdir = Files.createTempDirectory("jsp").toFile();
tempdir.deleteOnExit();
handler.setAttribute(ServletContext.TEMPDIR, tempdir);

And of course you can configure various init parameters of the JettyJspServlet (see documentation at https://eclipse.dev/jetty/documentation/jetty-12/operations-guide/index.html#og-configuration-of-the-jsp-servlet and default configuration –when using non-embedded Jetty, so to be replicated with embedded Jetty– at https://github.com/jetty/jetty.project/blob/ea8139e94a6918b6edb2a3a1e8e83af45f0057ab/jetty-ee10/jetty-ee10-webapp/src/main/config/etc/webdefault-ee10.xml#L181-L219). At a minimum you'll want to set "development" to false when running in production. The temporary directory above could also be configured as "scratchDir" init parameter on the servlet.