like WSDL what is the contract for RESTful service it exposes to client. Are there any java frameworks to create the client automatically for consuming RESTful Services ?
In REST your media types and your link relations are your contracts. It is possible you use WADL as a runtime discovery mechanism, but it is far less flexible than using hypermedia based representations.
REST systems should never use something like WADL to generate client proxy classes.
Jersey is probably the most popular REST library for Java on the server. They also have client libraries that allow you to consume RESTful services with an example
The RESTful equilivant of a WSDL is a WADL
REST services use what's called "uniform contract" or "uniform interface", which is based on http verbs. Thus, the contract of a REST service is a combination of the uniform interface and the URIs it support.
To call a SOAP service we pick an operation and the address specified in the concrete section of that services's WSDL definition.
To call a REST service we pick an http verb and a URI.
Related
We have currently implemented SOAP endpoints with CXF (Spring Boot). In accordance with the contract-first approach, we provide a WSDL, generate Java objects, and services from it (cxf-codegen-plugin) and finally implement the service interface.
This is all very nice and simple, but we only need the SOAP XML or the corresponding DOM tree. Not only is the conversion to Java objects unnecessary, we also have to convert them back to XML and lose some information from the original XML.
As far as I understand is SAAJ (SOAP with Attachments API for Java) exactly right here, or am I missing something? At most all resources about SAAJ are quite old and "low level". I cannot find good resources for that kind of approach.
In addition, we want to implement new services as microservices soon and are currently reviewing Quarkus and Apache Camel. However, I cannot find a (simple) way to create corresponding endpoints from the WSDLs, via which we then receive the SOAP message as plain XML / DOM tree.
In jax-ws, message-level access can be accomplished on the server side using web service Provider-based endpoints, and on the client side using Dispatch clients.
A web service Provider-based endpoint offers a dynamic alternative to the Java service endpoint interface (SEI)-based endpoint. Unlike the SEI-based endpoint that abstracts the details of converting between Java objects and their XML representation, the Provider interface enables you to access the content directly at the XML message level—without the JAXB binding. web service Provider-based endpoints can be implemented synchronously or asynchronously using the javax.xml.ws.Provider or com.sun.xml.ws.api.server.AsyncProvider interfaces, respectively.
See https://cxf.apache.org/docs/provider-services.html for details
I saw these two links:
1.SOAP vs REST
SOAP vs REST 2
I understood the difference between the two. But I also heard about WADL (https://wadl.java.net/), which are used along with REST to provide a contract ( similar to SOAP WSDL does)
Now I have two questions:
REST is also adheres to the data type that is going to receive or transmit by WADL, which now acts very similar to SOAP ( with WSDL ).
If REST with WADL and SOAP are similar, which one to use?
Thanks in advance.
SOAP (Simple Object Access Protocol)
REST (Representation State Transfer)
SOAP and REST can’t be compared directly, since the first is a protocol and the second is an architectural style.
The main difference between SOAP and REST is the degree of coupling between client and server implementations. SOAP works like a custom desktop application, tightly coupled to server. There is rigid contract between client and server and everything seem like breaking is any of the side is changed. But, REST client is more like a browser. It’s a generic client that knows how to use a protocol and standardized methods. If done right, there would be less coupling.
A client is supposed to enter into REST without prior knowledge of the API, except for the entry point and the media type. In SOAP, the clients need to have the prior knowledge of everything it will be using.
REST is protocol independent. It’s not coupled to HTTP. We can use it for any protocol for which there is standardized URI scheme. But, SOAP itself is a protocol.
SOAP only supports XML, but REST supports different format like text, JSON, XML etc. And we know if we use JSON then definitely we will be in better place in terms of payload.
SOAP can use any generic transport (HTTP / HTTPS) or RPC (Remote Procedural Call). But, REST uses only HTTP/HTTPS
SOAP can’t use REST. But, REST can use SOAP similar to HTTP or any other protocols
SOAP used services interfaces to expose the business logic. REST used URI to expose the business logic
In Java, JAX-WS is for SOAP web services. But, Java JAX-RS is for REST web services
SOAP defines the standards to be strictly followed. REST doesn’t define any standards like SOAP
SOAP requires more bandwidth and resource than REST. REST required less bandwidth and resources.
SOAP defines its own security. REST inherits security measures from underlying transport
SOAP is less preferred these days as compared to REST
RESTful and SOAP WebServices are fundamentally different.
In short - SOAP is a typical RPC based call where you hide your request action and details within the XML document of the SOAP body. Wheras pure RESTful webservie totally rely on HTTP methods to perform an action on server.
Although WADL is not yet widely adopted and not really a standard but the theory behind it is to simply help tools to generate some code, and it aims to promote reuse of applications beyond the basic use in a web browser i.e. machine-to-machine communication (still using HTTP protocol).
I'm a newbie to webservice, and I've read this chapter (and some other articles) to get an idea about SOAP. Sad, I couldn't find the next chapter about WSDL in java.net.
Anyway, let's suppose I need to implement SOAP 1.1/HTTP 1.1.
The used "contract" to exchange information is WSDL.
So, in order to create webservices provider :
What would be the role of JAX-WS?
Would it be needed or is it an alternative to WSDL?
If needed, shall we combine it with ( SOAP/HTTP + WSDL)?
What would be the role of JAX-WS in this combination?
Could it be replaced by JAX-RPC (or by something else)?
Is JAX-WS cross-platform or only specific to Java?
If moving to another platform, such as C or C++ or Python, would we be able to use JAX-WS if needed to be combined?
Talking C#,.Net... Is JAX-WS similar to WCF?
Thank in advance :)
SOAP and HTTP are message protocols. JAX-WS is the implementation in java for generating these messages. It handles all the low level details of converting java objects to SOAP messages, generating java classes based on WSDL and XSDs. JAX-WS is used for creating SOAP based as well as Rest based messages. It is the underlying technology that handles the messages on both client and server side. JAX-WS implementation is based on WSDL and SOAP standards. It is java specific.
I am not aware of what WCF is.
SOAP 1.1/HTTP 1.1.
SOAP(XML based Message protocol) over HTTP(Transport Protocol)
The used "contract" to exchange information is WSDL
Everyone wants to define their own way and framework to describe their webservice. So Microsoft has created contracts for WCF framework.The content of the WSDL document defines the contract of the web service for ex. service, data, fault, message contracts. RIP developers.
What would be the role of JAX-WS?
JAVA API for XML based web services. Use to create soap based webservice provider. It uses annotations.
Would it be needed or is it an alternative to WSDL?
JAX-ws is a framework or API.It is an alternative to WCF, you can say not WSDL. WSDL is a document which describes your webservice in XML format.
If needed, shall we combine it with ( SOAP/HTTP + WSDL)?
What would be the role of JAX-WS in this combination?
JAX-WS can implement SOAP/HTTP based webservice. USing JAX WS, you can generate WSDL which will describe your defined service implementation.
Could it be replaced by JAX-RPC (or by something else)?
yes, JAW-RS would also work.
Is JAX-WS cross-platform or only specific to Java?
JAX_WS is only specific to java. But you can design/implement webservice using JAX-ws which would be cross-platform.
If moving to another platform, such as C or C++ or Python, would we be able to use JAX-WS if needed to be combined?
You can use jax ws implemented webservice provider to interact with any other language based webservice client.
Talking C#,.Net... Is JAX-WS similar to WCF?
JAX-WS, WCF both are framewrok to implement webservice in java, .net respectively.
Note: You are quite confused between language, framework, protocol, implementation methods etc. Your questions are very ambiguous. Keep Learning.
I've restful web service. I created a restful java client which can abstract connection details and expose beans to set the data. Now what happen if my web service has to be consumed by different platform than Java ? Wouldn't it had been better to avoid the client itself and let consumer make direct HTTP call ?
WADL (https://wadl.java.net/) is the WSDL-equivalent for RESTful services, however, it is not very widely used by now.
Edit: A reason why it might be not popular can be found in this article: http://bitworking.org/news/193/Do-we-need-WADL
I have a backend system that currently returns a domain object. I want to build a REST & SOAP front end using mule. To create responses that are REST or SOAP based, and ensure that the backend is protocol agnostic, I am thinking about creating two protocol adapters (REST and SOAP). It is unclear to me if it is better to create a mule translator for the service, which understands the protocol and delegates to generate an appropriate response, or just create two class interfaces (using JAX-RS/JAX-WS annotations) to the service.
I'm not finding much literature, best practices, or design patterns on the subject. Can someone point me to some useful material or provide their opinions?
Writing transformers for message formatting would be a waste of time.
You should write service classes with JAX-RS/JAX-WS annotations, transports exist for both.
For a REST service you can use the Jersey transport:
http://www.mulesoft.org/documentation/display/JERSEY/User's+Guide
For SOAP service you can use the CXF transport (also supports JAX-RS):
http://www.mulesoft.org/documentation/display/CXF/Building+a+web+service
Note: You don't need mule for this at all, both Jersey and CXF run in a servlet container like tomcat.