Web Service Basics for Android notes

First, Web Service What is it?

is the network service, according to the definition, webservices (Web services) is a software system that supports the interoperability of different machines between networks, a self-contained, self-describing, and modular application that can be described, published, and invoked in a network, and can be viewed as a network-based, Distributed, modular components.

Web Servicesis based on a common protocol, includingHTTP,SOAP,UDDI,WSDLand so on. WhichWebServiceThe three elements areSOAP,WSDLand theUDDI.  SOAPA format used to describe the delivery of information,WSDLTo describe how to access a specific interface,UDDIused to manage, distribute, queryWebService.

(Above the bold part of the content from the Baidu Encyclopedia)

webservices Has the advantage of providing interoperability between different application platforms, which enables component-based development and Web combined to achieve the best results. It is based on the HTTP Protocol, the call request and the response message can pass through the firewall, do not need to change the firewall settings, so as to avoid the use of special ports to communicate with the problem of unable to cross the firewall.

Inductive Summary-- A Web service is an application that exposes an API that can be called through the Web .

In fact, plainly, is a server, you can understand for the website, open up (that is, public) a function or method, we passWebServiceprogramming allows you to get the information it exposes so that you can use it for yourself. For example, a weather site that exposes its weather interface, we canWebServiceget to the daily local weather conditions. It is important to note that, as mentioned above,WebServiceis based on a common protocol, and thisJAVAlike,have a good cross-platform cross-language features! but that's the way it says,WebServiceis that really the case? I'm not yet known for my practice, but this blog post is a historical biography .

Some things. We can take a few details--

SOAP and the WebService of those things

Second, SOAP , WSDL with the UDDI

above, SOAP wsdl and uddi is web Service soap and wsdl uddi

( 1 ) SOAP

The full name isSimple Object Access Protocol,Simple Object Access Protocol,is used to exchangeXML(Standard Universal Markup Languagea subset of the following) to encode information in a lightweight protocol. There are currently two versions commonly used,SOAP1.1and theSOAP 1.2. SOAPThe advantage of this is that it can run on any other protocol, such assmtp,httpand so on.

( 2 ) WSDL

The full name is (Web Services descriptionlanguage, or Web Service Description language) is an XML language used to describe Web services, which describes the functions, interfaces, parameters, return values, and so on of Web services, so that users can bind and invoke services. It defines related actions and messages for a given Web service invocation and response in a language-neutral way.

WSDL is something we can actually see, it's a XML document that describes a Webserivce in every aspect.

If you read the above words, you still can't understand WSDL , then please read the following: (from a netizen, below the source)

How would you tell someone about your webservice function, and what are the parameters of each function call? You may write a set of documents yourself, and you may even verbally tell people who need to use your webservice. These informal approaches have at least one serious problem: when programmers sit in front of a computer and want to use your Web service, their tools (such as VisualStudio) can't help them because they don't know your Web service at all. The solution is to provide a formal description document in a way that the machine can read. WebService Description Language (WSDL) is an XML-based language that describes WebService and its functions, parameters, and return values. Because it is XML-based, WSDL is both machine readable and human readable, which is a great benefit. Some of the latest development tools can generate WSDL documents based on your WebService, import WSDL documents, and generate code that invokes the corresponding Web service. so the WSDL was born.

Source Document < http://sakyone.iteye.com/blog/353063 >

( 3 ) UDDI

the full name is: Universal Description, Discovery andintegration " , Chinese translation is "General description, Discovery and Integration Services", or it can be called "Unified description, Discovery and Integration protocol". It feels very abstract, I think so, haha. It's okay, keep looking.

The following instructions are too professional, not understanding, so the original quote--

Understanding WEB Service Specifications: Part 3rd: Unified Description, Discovery, and Integration (UDDI)

when all applications are on-premises, it is easy to find the features you want. However, You cannot get the benefits of a central registry when using distributed systems such as WEB services. Distributed systems are also prone to change. And that 's where UDDI comes in. It is intended for two purposes. When it was originally formed, it was considered a "universal Business Registry". The idea is that businesses can search for partners using one of the following three methods:

• White Pages: White pages are similar to white pages used to find company information in a phone book. For example, if you know the name of a company, you can find the address of the company, how to contact it, and even determine which person in your organization to contact.

Yellow Pages: Similarly, the Yellow pages are the same as the yellow pages in the phone book, Where you can find your company by category. uddi A variety of taxonomies are specified for each company to use to classify itself. For example, if you are looking for sporting appliances, you can find their North American Industrial Classification system ( north American Industry Classification System naics " code is 339920 company.

• "Green page": There is no green page in the phone book, but the idea here is that companies can use this search method to find trading partners that implement a particular service. For example, you can search for a company that implements a distance calculation feature that uses postal codes.

UDDI It is also considered a way to keep distributed applications running for long periods of time. The idea is that you can cache information about access to a particular service, and if the client crashes, the application will automatically go back to the registry and check to determine if the information has changed. If it has changed, you can make changes directly within the application (and, ideally, automatically make changes) and retry your request.

after reading, probably understand, UDDI is actually Business Registration Logic and registration, allowing users to quickly find.