Introduction I’ve talked before about Jetty as an embedded servlet container. Jetty also includes some useful utility servlet implementations, one of which is ProxyServlet. ProxyServlet is a way to create an HTTP or HTTP/S proxy in very few lines of code. Even though it’s part of the Jetty project, it’s modularized to be independent of the Jetty server, so you can use it even in cases where the servlet won’t be run in Jetty.

As I discussed in a series of four posts (see Part 1, Part 2, Part 3, and Part 4), I recently taught a class on Spring WebMVC and how it can be used to REST-enable a standalone Java application. As part of that discussion, I talked about using Jetty as an embedded servlet container, which let us create and access servlets without having to package our existing application as a WAR.

This is part 4 of a series discussing a sample webapp that uses Spring WebMVC and Jetty to add a REST API to a standalone Java application. Part 1, Part 2, and Part 3 were posted previously. This post discusses using Spring WebMVC for the client side, and also discusses some integration options for adding WebMVC to an existing application. WebMVC Client Of course, one of the largest motivations for a REST API is the ability to use it from any language, especially JavaScript in a browser.

This post is part 3 of a series that started here and continued here. There will be at least one more post in this series, to discuss Spring WebMVC as a client. All of the code is available as a project on GitHub. As I discussed previously, the Spring WebMVC example I provided is a complete web application, with the three files web.xml, rest-servlet.xml, and the controller class. But one of the reasons I wanted to put together this example is to show the class I was teaching the possibility of embedding this into an existing Java program.

Last time I introduced an example application I wrote to illustrate Spring WebMVC for a Java class. I think the application is a nice example because it also illustrates the ability to add a REST API to an existing standalone Java application using Jetty as an embedded servlet container. I’m presenting this example in a series of posts because I learned from personal experience teaching this that the more “under the covers” behavior there is, be it classpath scanning, annotation configuration, reflection, or proxying, the harder it can be for new folks to grasp.

While giving a series of presentations on using Java in a distributed environment (focusing on Java EE and Spring), I got a lot of interest in web programming. I did an extra presentation on servlets, but I didn’t want to leave it there, because writing Java servlets directly is not very efficient compared to tools like Spring WebMVC. So I made an extra presentation on WebMVC, which led me to make a sample application that provides both a client and a server using Spring WebMVC.

This is part 1 of 3. Also see part2 and part3. There are a lot of tutorials out there about providing REST web services in a servlet container by building and deploying a WAR. There are also cases where someone is looking to put a REST interface on an existing Java application. In that case it isn’t always possible to turn the application into a WAR or EAR and adding a servlet container as a separate process just adds a layer of complexity.