How to implement backward compatible soap webservi

问题:

One of our product publishes a webservice using contract-last approach. This has becoming a real problem as all of our clients (ws clients) have to rebuild their client apps as soon as we release a new version of our product. This is due to all namespace changes that comes as a cost with auto-generated wsdls. We use Axis1 for javatowsdl. I've been seeking for a good methodology/ tool to develop backward compatible webservice for this.

i.e. version 9.3 clients can still hit the 10.0 service, of cause they will miss some of the functionality, that is fine. But they should be able to function without breaking.

I do understand the whole problem is due to our contract last approach (Pls. correct me if I'm wrong). Therefore, if the solution is to go for contract-first webservice what are the tools and technologies I could use? Also what are the best practises around contract-first?

Thanks in advance.

回答1:

As you already realized, the recommendation is to use a Contract-First (or Top-Down) approach to develop Web Services. That implies a manual definition of your WSDL interface and generate a Java Skeleton of the Web Service based on this document using automatic tools.

Is important that your WSDL complies to the WS-I standart to assure interoperability between clients on different platforms. You can use SOAP-UI to test whether your WSDL is compatible with the standard or not.

For the Skeleton generation, there are several Web Service Runtime API's that you can use: Like Apache Axis and JAX-WS. I personally prefer JAX-WS because is a Java Standard and is supported by all Java EE Containers. Each container provides tools for the Skeleton generation, Weblogic has some nice Ant Task for that but there's also WS-Import that is Container neutral.