XML Web Service is the basic building block for distributed computing on the Internet. Open standards and focus on communication and collaboration between users and applications create an environment in which XML Web Service becomes a platform for application integration. The editor of Wulin.com recommends this to teach you the basics of learning XML Web Service SOAP. Here are also tutorials about web xml. I hope you can like and learn something to improve your knowledge and skills. The following is a detailed reading of the content: What is XML Web Service?
XML Web Service is the basic building block for distributed computing on the Internet. Open standards and focus on communication and collaboration between users and applications create an environment in which XML Web Service becomes a platform for application integration. Applications are constructed using XML Web Services from multiple different sources, which work together regardless of where or how they are implemented.
The number of XML Web Service definitions that can be found in the number of companies that build XML Web Services. However, almost all definitions have the following commonalities:
1. XML Web Service provides useful features to Web users through standard Web protocols. In most cases, the SOAP protocol is used.
2. XML Web Service can describe its interfaces in great detail, which enables users to create client applications to communicate with them. This description is often included in an XML document called the Web Service Description Language (WSDL) document.
3. XML Web Service has been registered so that potential users can easily find these services, which is done through Universal Discovery, Description, and Integration (UDDI).
One of the main advantages of the XML Web Service architecture is that it allows various programs written on different platforms and in different languages to communicate with each other in a standard-based manner. Users who know some of this industry may immediately say: Wait, haven’t CORBA and previous DCEs made the same promises? What’s the difference between this and them? The most important difference is that SOAP is much simpler than the previous methods, so there are much fewer obstacles to implementing standard-compatible SOAPs. The last time I counted, the list already contained 79 items. As you might expect, most large software companies offer SOAP implementations, but there are many implementations created and maintained by individual developers. Another great advantage of XML Web Service is the use of standard Web protocols - XML, HTTP, and TCP/IP, compared to previous solutions. Many companies have established web infrastructure, and their employees have the corresponding knowledge and experience in maintenance. Therefore, introducing XML Web Service is much cheaper than introducing previous technologies.
We define XML Web Service as: software services provided on the Web through SOAP, using WSDL files for descriptions, and registering through UDDI. Then, you might ask: What can you do with XML Web Service? The original XML Web Service is usually a source of information that can be easily incorporated into the application, such as stock prices, weather forecasts, sports results, and more. It's easy to think of a whole class of applications that can be built to analyze and aggregate the information you care about and provide it in various ways; for example, you can use a Microsoft? Excel spreadsheet to aggregate all your financial information - stocks, 401K, bank deposits, loans, and more. If you can obtain this information through the XML Web Service, Excel can constantly update it. Some of this information is free, while others may require a subscription to obtain the corresponding service. Most of this information is now available on the Web, but XML Web Service makes programming access easier and more reliable.
Provide existing applications in XML Web Service, which can build new and more powerful applications and leverage XML Web Service as a building block. For example, a user can develop a procurement application to automatically obtain price information from different suppliers, allowing the user to select suppliers, submit orders, and then track the shipment of goods until the goods are received. In addition to providing services on the Web, suppliers' applications can also use XML Web Service to check customers' credit, collect payments, and go through freight procedures with freight companies.
In the future, some of the most interesting XML Web Services supported applications can also leverage the Web to complete tasks that are currently unsuccessful. For example, the Calendar Service is one of the services that will be supported by the Microsoft .NET My Services project. If your dentist and mechanic provide their schedules through this XML Web Service, you can schedule appointments with them via the Internet; if you prefer, they can also make dates for cleaning and daily maintenance directly on your calendar. It is not difficult to imagine that you can create hundreds of applications as long as you can program the web.
SOAP
Soap is the communication protocol of XML Web Service. When SOAP is described as a communication protocol, most people think of DCOM or CORBA and ask questions such as how SOAP activates objects? or what kind of naming services does SOAP use? Although the SOAP implementation may include the above, the SOAP standard does not specify it. SOAP A specification that defines the XML format of messages - this is a necessary part of the specification. A properly structured XML segment contained in a pair of SOAP elements is a SOAP message. Is this very simple?
Other parts of the SOAP specification describe how to represent program data as XML and how to use SOAP for remote procedure calls (RPC). These optional specification parts are used to implement applications in the form of RPC, where the client will issue a SOAP message (including the callable function, and the parameters to be transferred to the function), and the server will then return a message containing the result of the function execution. Currently, most SOAP implementations support RPC applications because programmers who are accustomed to developing COM or CORBA applications are familiar with the RPC form. SOAP also supports documentation applications, in which SOAP messages are just a wrapper of XML documents. Documented SOAP applications are very flexible, and many new XML Web Services take advantage of this feature to build services that are difficult to implement with RPC.
The last optional part of the SOAP specification defines the style of HTTP messages that contain SOAP messages. This HTTP binding is very important because almost all current OS (and many previous OS) support HTTP. Although HTTP binding is optional, almost all SOAP implementations support HTTP binding because it is the only standard protocol for SOAP. For this reason, people often mistakenly believe that SOAP must use HTTP. In fact, some implementations also support MSMQ, MQ series, SMTP or TCP/IP transmission, but because HTTP is very common, almost all current XML Web Services use it. Because HTTP is the core protocol of the Web, most organizations’ network infrastructure supports HTTP and employees have learned how to manage it. Today, an infrastructure for security protection, monitoring and load balancing for HTTP has been established.
When you start using SOAP, the easiest thing to confuse is the difference between the SOAP specification and its many implementations. Most users who use SOAP do not write SOAP messages directly, but use the SOAP toolkit to create and analyze SOAP messages. These toolkits usually convert function calls from a certain language to SOAP messages. For example, Microsoft SOAP Toolkit 2.0 converts COM function calls to SOAP, while Apache Toolkit converts JAVA function calls to SOAP. The type of function call and the data type of supported parameters vary depending on each SOAP implementation, so functions that apply to one toolkit may not apply to another toolkit. This is not a limitation of SOAP, but a limitation of the specific implementation scheme used.
By far, the most striking feature of SOAP is that it can be implemented on many different software and hardware platforms. This means that SOAP can be used to link different systems inside and outside the enterprise. Various methods have been tried in the past to propose a common communication protocol that can be used for system integration, but none of them have gained wide recognition like SOAP. Why? Because SOAP is smaller and easier to implement than many earlier protocols. For example, the implementation of DCE and CORBA takes years, so only a few implementation solutions have been released. SOAP can do most of the hard work with existing XML parsers and HTTP libraries, so the SOAP implementation can be completed within months. This is why there are now more than 70 SOAP implementations. Of course, SOAP does not have all the functions of DCE or CORBA. Although the functions are reduced, SOAP is easier to apply due to its greatly reduced complexity.
The popularity of HTTP and the simplicity of SOAP enable you to call them from almost any environment, thus becoming the ideal foundation for XML Web Services.
End. The tutorial has been finished here. Have you gained something from reading? This site also provides web xml-related content, welcome to continue reading.