JAX-RS is a specification that helps you develop restful web services in Java.
But JAX-RS seem to be requiring a servlet container like "Tomcat"or "Jetty".
Managing container in a clustered mode is painful and more operations heavy.
Is there way to start JAX-RS service like a normal Java program/application ?
I want to use JAX-RS implementation but I don't want to follow typical"deploy" cycle.
JAX-RS is strongly linked to HTTP, hence most implementations (eg Jersey, Apache CXF) run in a servlet, which in turn runs in a container such as Tomcat or Jetty. I guess you could develop your own standalone JAX-RS implementation, but you'd end up reinventing the wheel as you'd be forced to implement most aspects of a web server.
Your worries about clustering also seem unfounded. Clustering Tomcat is simple, it is a very common thing to do and there's plenty of information available on the subject. It seems like clustering a custom implementation would actually be a much harder job.
Related
I would like you guys to give me some feedback, on my understanding about the
difference between Application Servers such as JBoss and frameworks such as Axis and CXF.
CXF is a standalone, web-app based framework that
implements JAX-RS, JAX-WS API wich, in turn, are part of the
larger API set of JEE.
Being a web-app based implementation, it
can only be used to host "SOAP on HTTP" services even if the
standard JAX-WS defines other possible channels for SOAP
messages,such as SMTP.
Application servers,such as JBOSS, instead implement JAX-WS as well as all the other JEE APIs in a more "native" and direct way, so,for example, they can be used to host also SOAP on SMTP services.
Both AS and standalone frameworks such as CXF and AXIS make
extensive use of Inversion of control.
Application Servers, such as Jboss, can be thought as composed by a
set of frameworks that implement all the JEE stack API.
Please take some time to correct/enhance the above statements.
Thanks
Working on a Java-based large distributed system, so there will be multiple services running across multiple machines .....
Looking for an open source framework to be able to manage these services(e.g. start/stop a service, install a new a service remotely etc.)
Apache Karaf seems to be a good choice, but underneath it uses apache felix (an OSGi reference implementation) bundle which I have a hard time to really understand. In particular, it seems to be easy to define and register a service in felix, but how do you invoke such a service remotely? Do you need to have a separate RPC mechanism to achieve that? There seems to be very few links describe it. In general how do people use OSGi? Is Apache felix out of date?
Any other framework that can be used to manage services assuming I will have my own RPC layer (say RMI based or Netty based)?
I guess you have to specify the way you define a service.
There are services, like remote services that use RPC mechanism, for example EJB remote calls.
Another way to define services is to talk of Web-Services, either using SOAP(XML) or JAXRS(JSON) as transport protocol. And there is the definition of services in OSGi which just means a separation of API (service definition) and implementation. As sum-up you could define OSGi as a SOA for Applications within the same VirtualMachine. (it gives much more, but this is one way to look at it from a service perspective)
Apache Karaf is a OSGi server that is comparable to a Application Server, only it works for OSGi applications. It brings a lot of convenience technologies on top of a choosable OSGi framework. That would be either Apache Felix or Eclipse Equinox. Both are OSGi frameworks that provide the basic OSGi infrastructure - SOA in the same JVM.
Now there are a lot of other benefits of it, like starting and stoping services, updating services.
Taking the RPC into account this can easily be achieved, by combining OSGi-Services with CXF for example. It can easily be configured to export an OSGi service as CXF service. (this is very Karaf/CXF specific)
Apache Karaf itself also supports clustering with Apache Karaf Cellar, which also provides a DOSGi service for easier communication of services across cluster groups. DOSGi stands for Distributed OSGi, which can also be achieved by using CXF and much other implementations.
Apache Felix and OSGi in general are far away of being out-of-date. A lot of Java EE Application servers use OSGi as their underlying technology to be modular and have a smaller footprint.
That would be GlassFish, Websphere, Geronimo etc...
I am looking to use Jersey without the need of installing an application server such as Tomcat or Glassfish. Ideally I would like to create a lightweight program that listens on a port and allows connections. I believe you can do this with Grizzly + Jersey but I am not sure how easy this is, because from my understanding Grizzly is used to write new http servers from scratch?
Restlet looked good in this regard because it included an internal http server but the documentation provided is extremely meager.
You can use a light-weight servlet container like jetty. you can bundle and ship this with your application. Also building and shipping jetty with your application is very easy.
I've deployed an app recently that uses embedded Jetty in Spring to launch Jersey, so this is 100% possible. Jersey, in fact, has a SpringServlet for easy delegating to a Spring context based REST implementation. If you have additional questions down this route, let me know. It wasn't the most straight forward, but I can talk you through some of it with the appropriate links.
I am in the process of writing a JSON based web service. The service will accept two types of requests: commands (e.g. createOrder) and queries (e.g. getOrders). Each request needs to send user credentials (username/password) for authentication (perhaps in HTTP headers). The service needs to be implemented in Java.
Which frameworks would you recommend for this use case? The very basic stack that I am thinking of is servlets backed by a JSON framework like Jackson. Are they any other frameworks that you would recommend and why? There is no need or desire to make the service RESTful, however smooth integration with Java EE 6 or Spring would be a plus.
Thanks in advance for your time.
Can I then interest you in RESTful Web Services (which is a JAX-RS API)? A library that implements JAX-RS is Jersey, Apache CXF, which is suited to allow JSON Web Service.
A related StackOverflow Post which shows REST clients that conforms to JAX-RS.
You should take a look at spring mvc and read this blog post which cover using spring mvc for restful WS.
Play! Framework would definitely fit your bill. It is not servlet-based but fulfills all of your requirements. Plus development with Play is very fast, you can get a prototype up and running in no time.
I personally use Apache CXF, with JAX-RS and jackson libraries. They are easy to implement and integration is dead easy. JAX-RS is a java standard, Jackson library is fast and handles circular references and Apache CXF needs only a couple of lines of configuration to setup and start running. Go for it!
An Open-Source Services Framework From Apache
-CXF has been designed to provide a pluggable architecture that supports not only XML but also non-XML type bindings, such as JSON and CORBA, in combination with any type of transport.
-Java EE integration: deploy services in Java EE application servers such as Apache Geronimo, JOnAS, Redhat JBoss, OC4J, Oracle WebLogic, and IBM WebSphere
-Standalone Java client/server
I am not much aware about the details as to which web servers support Web services written in Java.
Would Like to know the following three things:
1) What is required to have support for Web Services : Only Servlet Container or An Application Server + Web container?
2) Would like to know that do all Web Server supporting web development in Java support Web Services?
3) How to identify whether a particular server supports Web Services or not?
Thanking you in advance.
Your question is somewhat unclear. The term web service is applied to anything from a REST style API to SOAP based services to JSON based, etc etc. Wikipedia says an equivalent is a Web API, and an API can be pretty much anything.
So to answer your question. A servlet container is enough to support most common types of web services, it doesn't require an application server. Take a look at Apache CXF, which is a framework catering for a lot of web services styles (notably SOAP and REST).
Apache CXF is a rather large framework, and can take some time to get your head around. If you need something simpler, you may be better off looking at some object serialization frameworks and implement the servlets yourself (this is what I do mostly). To serialize to XML, use out-of-the box Java JAXB annotations. To serialize to JSON, use Jackson.
Assuming you're talking about SOAP WS-* web services via JAX-WS.
Java EE 5+ stipulates support for JAX-WS compatible web services within the container, both at the Web App level, and at the EJB level. So, any full boat, modern, App Server will have JAX-WS support built in.
Servlet 2.x and 3.0 do not have a requirement to support JAX-WS at the container level, but all of the major implementation of JAX-WS can be deployed within a WAR in a modern Servlet container (like Tomcat).
Java EE 6 offers a Web Profile, but the Web Profile does not include JAX-WS. Java EE 6 Full Profile includes both JAX-WS (SOAP, WS-* web services), and JAX-RS (for HTTP and more RESTful web services).
So.
If you bundle your own implementation, all of the containers should accommodate you. If you want it built it to the container, you'll need a full Java EE 5 or Java EE 6 App Server.