I have been working on an example application for Lucene and Solr for my upcoming talk at the Java User Group Karlsruhe. As a web framework I wanted to try Dropwizard, a lightweight application framework that can expose resources via JAX-RS, provides out of the box monitoring support and can render resource representations using Freemarker. It's really easy to get started, there's a good tutorial and the manual.
An example resource might look like this:
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
@Path("/example")
@Produces(MediaType.TEXT_HTML)
public class ExampleResource {
@GET
public ExampleView illustrate() {
return new ExampleView("Mot\u00f6rhead");
}
}The Resource produces HTML using Freemarker, which is possible if you add the view bundle in the service. There is one method that is called when the resource is addressed using GET. Inside the method we create a view object accepting a message that in this case contains the umlaut 'ö'. The view class that is returned by the method looks like this:
import com.yammer.dropwizard.views.View;
public class ExampleView extends View {
private final String message;
public ExampleView(String message) {
super("example.fmt");
this.message = message;
}
public String getMessage() {
return message;
}
}It accepts a message as constructor parameter. The template name is passed to the parent class. This view class is now available in a freemarker template, an easy variant looks like this:
<html>
<body>
<h1>${message} rocks!</h1>
</body>
</html>
Accessing the resource using curl works flawlessly:
curl http://localhost:8080/example
<html>
<body>
<h1>Motörhead rocks!</h1>
</body>
</html>Why is that? It's Servlet Programming 101: You need to set the character encoding of the response. My Firefox defaults to ISO-8859-1, curl seems to use UTF-8 by default. How can we fix it? Tell the client which encoding we are using, which can be done using the Produces annotation:
@Produces("text/html; charset=utf-8")So what does it have to do with Dropwizard? Nothing really, it's a JAX-RS thing. All components in Dropwizard (Jetty and Freemarker notably) are using UTF-8 by default.
About Florian Hopf
I am working as a freelance software developer and consultant in Karlsruhe, Germany and have written a German book about Elasticsearch. If you liked this post you can follow me on Twitter or subscribe to my feed to get notified of new posts. If you think I could help you and your company and you'd like to work with me please contact me directly.
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