参考A
http://www.ajousou.com/netvsj2ee.html

Service Publishing, Discovery, and Binding

Once a Web Service has been implemented, it must be published somewhere that allows interested parties to find it. Information about how a client would connect to a Web Service and interact with it must also be exposed somewhere accessible to them. This connection and interaction information is referred to as binding information.

Registries are currently the primary means to publish, discover, and bind Web Services. Registries contain the data structures and taxonomies used to describe Web Services and Web Service providers. A registry can either be hosted by private organizations or by neutral third parties.

IBM and Microsoft have recently announced the Web Services Inspection Language (WSIL) specification to allow applications to browse Web servers for XML Web Services. WSIL promises to complement UDDI by making it easier to discover available services on Web sites not listed in the UDDI registries.

J2EE

Sun Microsystems is positioning its Java API for XML Registries (JAXR) as a single general purpose API for interoperating with multiple registry types. JAXR allows its clients to access the Web Services provided by a Web Services implementer exposing Web Services built upon an implementation of the JAXR specification.

There are three types of JAXR providers:

    * The JAXR Pluggable Provider, which implements features of the JAXR specification that are independent of any specific registry type.
    * The Registry-specific JAXR Provider, which implements the JAXR specification in a registry-specific manner.
    * The JAXR Bridge Provider, which is not specific to any particular registry. It serves as a bridge to a class of registries such as ebXML or UDDI.

.NET

At first, Microsoft had the discovery of Web Services with DISCO in the form of a discovery (DISCO) file. A published DISCO file is an XML document that contains links to other resources that describe the Web Service. Since the wide spread adoption of UDDI, however, Microsoft has supported it in order to maximize interoperability between solutions in what is, after all, a set of specifications for interoperability.

In addition to providing a .NET UDDI server, the UDDI SDK provides support for Visual Studio .NET and depends on the .NET framework. Products such as Microsoft Office XP offer support for service discovery through UDDI.

参考B
http://www-128.ibm.com/developerworks/websphere/techjournal/0202_kraft/kraft.html
Currently, there is no support for additional discovery mechanisms, such as .NET's file-based discovery approach (DISCO). However, it remains to be seen how the proposed DISCO approach can establish itself as an open standard, or if it will be superseded by the Web Services Inspection Language (WSIL). WSIL was proposed by IBM and Microsoft to complement UDDI in advertising Web services, which is similar to the file-based discovery approach using DISCO. It might be possible that WSIL will replace DISCO, since IBM and Microsoft have announced their intentions of submitting the WSIL specification to a standards body.