Java Web Service Advanced

With the recent release of Sun Microsystems's Java Web Services developers Pack (Java WSDP) version 1.0, Java Developers can now have a convenient, All-in-one download package to help Jav A platform to develop WEB services. The Java WSDP contains all Java APIs for XML in the Java XML Pack (Java APIs for XML (JAX)) and includes Apache Tomcat servers and a full-featured environment for development and test WEB services Additional components that are required. All the techniques in the Java XML Pack were published a year ago in the Java WSDP and passed all the design review requirements of the Java Community Process (JCP).

Java WSDP is not a product, but more inclined to the WEB Service standard reference implementation, it is a convenient, easy to install the package. This package consists of a number of implementations that can be put into production and several components that should be used for testing purposes only. Therefore, the Java WSDP should not be an environment for deploying production applications, but rather an environment for developing and testing Web services; It is primarily used to help Java developers start learning to use Web services. Java WSDP is an excellent tool for understanding, developing, and testing Web services, and because it is based on open standards, it does not need to be restarted when you go to a new production environment.

What are the components in the Java WSDP?

When you install the Java WSDP distribution, you will create a directory where all components are located. By default, this directory contains a fully functional server environment that can be used to develop and test WEB services. The Java XML Pack contains all the Java APIs currently available for XML and contains the main components that support WEB services. The following is a list of Java XML Pack components and a brief description of the functionality of these components:

Java API for XML processing (Java API for XML processing (JAXP)): Jaxp is an pluggable API that is open to any vendor implementations of the XML APIs recommended by the consortium (i.e., SAX, DOM, and XSLT) 。 JAXP provides a standard interface for obtaining XML parsers; recently released Java platform (Java 2 Platform, Standard Edition SDK v1.4 (Java 2 Platform, Standard Edition SDK v1.4), see Resources for more information) Include JAXP as a standard interface. Like other Java interfaces, the JAXP reference implementation being developed has been assigned to other groups--in this case, Apache Software Foundation. Xerces 2 is the latest Apache XML parser, which is included in the Java 2 platform, the standard version of the SDK v1.4.

Java APIs FOR XML messaging (Java API for XML messaging (JAXM)): JAXM is designed to enable applications to send and receive document-oriented XML messages using a pure Java API. The purpose of JAXM is to provide a basis for higher-level, standards-based, messaging protocols such as EbXML that are based on SOAP messaging protocols. The SAAJ specification was recently detached from JAXM, which contains a synchronized SOAP connection, so JAXM is now primarily used for asynchronous messages. (I will have a more detailed discussion of SAAJ in the next.) When JAXM is used asynchronously, it uses a messaging provider to facilitate routing of messages. JAXM includes a messaging provider that is a reference implementation of the EbXML transmission, Routing and packaging (EbXML transport, Routing, and Packaging) specification version 1.0.

Soap APIs with attachments in Java (soap with Attachments API for Java (SAAJ)): SAAJ is a package that enables developers to produce and consume messages that follow the SOAP 1.1 specification and their contained SOAP attachments 。 SAAJ was originally defined as part of the JAXM 1.0 specification, but with the recent release of JAXM 1.1, SAAJ has been separated from a specification, so that other specifications can rely on SAAJ packages without relying on JAXM.

Java API for xml-based RPC (Java API for xml-based RPC (JAX-RPC): Jax-RPC is the implementation package that is used to support SOAP 1.1 xml-based RPC calls. The core JAX-RPC package contains one reference implementation for a full-featured JAX-RPC client that invokes a WEB service and a JAX-RPC server. In addition to the core package, the Java WSDP distribution includes a number of command-line tools that are used to build the client stub from the Web Service Definition language (Web Services definitions Language (WSDL) file) and to deploy server components.

Java APIs FOR XML registrations (Java API for XML registries (JAXR)): XML registries are often used to store information about published Web services, while the JAXR API provides a uniform way to access this information. The most common XML registry for WEB Services now is the unified description, Discovery, and integration (Universal Description, Discovery, and Integration (UDDI)) registry; Jaxr contains a provider for accessing UDDI.

In addition to the packages in the Java XML Pack, the Java WSDP contains a number of other components that make it a full-featured server environment for testing WEB services. Here is a list of these additional components that make the Java WSDP more complete:

Tomcat (Java servlet and JavaServer Page container): Apache Software Foundation is delegated to complete the task of creating and maintaining reference implementations for the Java Servlet container, including JSP and JSTL. Apache has developed an excellent open source solution that can match many commercial products in its usual way. The Java WSDP is distributed along with the Apache Tomcat 4.1.2, although the latter is now a beta release, but it is a reference implementation version of the Java Servlet 2.3 and Java Server Page 1.2. When writing this article, the latest version from Apache is Tomcat 4.0.4, which is also a reference implementation of Java Servlet 2.3 and JSP 1.2.

JavaServer page Standard Tag library (JavaServer Pages Standard Tag Library (JSTL): JSTL is a tag library that contains many of the common features commonly found in JavaServer page (JSP). Since JSTL uses only the functionality in the JSP 1.2 specification, you will need a JSP 1.2 container to use the tag library. Fortunately, the Apache Tomcat Server described above is just such a container, so you will be able to use the Java WSDP to test JSTL or develop your own tag library. JSTL has too many features that we can't describe in detail here, but if your JSP needs to access the database, manipulate XML, or perform standard formatting, you should consider using JSTL.

Registry server: The registry server is distributed along with the Java WSDP, a full-featured implementation of unified description, Discovery, and Integration (UDDI) version 2, which can be used to test the registration and discovery of WEB services. Unlike many other WSDP components, the registry server should be used only for testing purposes and therefore listed in the package's release notes to avoid redistribution with any other product. In addition to this limitation, the registry server is an excellent tool for learning and testing UDDI version 2 and is an essential part of the Java WSDP.

The Java WSDP also provides a number of other tools that help in the construction of Web service stub code and the deployment and management of Web service server-side components. The Java WSDP tutorial described below shows you how to use these other tools.