Soap and Web Services

The most important technology affecting the world is I n t e r n e t/I n t r a n e t,
I n t e r n e t/I n t r a n e t not only changes the lives of many people, but also affects the way the world operates. Various business opportunities
The development of software and hardware is also dominated by I n t e r n e t/I n t r a n e t. The emergence of I n t e r n e t/I n t r a n e t is also open
The method of sending has brought about multiple forms. Software Engineers began to use various tools to develop I n t e r n e t/I n t r a n e t
System. In the first round of important technological revolution, h t p, which is used by I n t e r n e t/I n t r a n e t and e-commerce
It has an important impact. The second round is the rise of the j a v a language. j a v a brings a cross-platform opportunity to make software
Component personnel can use a single language and Environment on various platforms to develop application systems,
J a v a provides almost a platform-crossing opportunity. The third round is the rise of x m l technology, which provides standards
The Data encapsulation technology enables data exchange across various platforms, operating systems, and development tools. Pass
XML, various applications are no longer a headache when exchanging data.

Regardless of various I n t e r n e t/I n t r a n e t Application Systems
What we need is a standard interface that allows them to call and
This is the concept of web service.

Since x m L provides data exchange standards, when different I n t e r n e t/I n t r a n e t Application Systems
When integrating with each other, you can directly use the x m l technology as the standard for communication and encapsulation. When
When I n t e r n e t/I n t r a n e t application systems need to call services provided by each other
As long as the agreed service entry point is encapsulated with x m L, the other party's
Service. In this way, not only the standard data exchange mechanism is achieved, but also the smooth use of x m l to integrate various
Same I n t e r n e t/I n t r a n e t application system.
This concept can be illustrated in Figure 1-1. For example, when a s p is executed on the WI n d o w s platform
To use services executed on the L I n u x platform, as long as both parties agree on a standard interface for service provision,
Then, a s p can use x m L to encapsulate standard calls, and then pass them through I n t e r n e t/I n t r a n e t
In remote l I n u x. The remote l I n u x can solve this problem when receiving the request encapsulated in x m L.
Analyze the information encapsulated by x m L, execute the services required by a s p, and then use the x m l encapsulation for execution.
And pass it back to the remote a s p.
After receiving the x m l encapsulation result returned by L I n u X, A S P retrieves the execution result from x m L.
To complete the work.

S o a p defines how to exchange type and structured information. It is a wire protocol and
Use x m L as the standard for information encapsulation. Web Service uses s o a P as the communication standard,
It also provides standard external service interfaces so that various client applications can be tuned through s o a p
Use service interfaces to use the functions provided by web service.

Because s o a P is only a wire protocol, it must be used in actual communication.
Specific communication protocols, such as h t t p, s m t p, Or I o p. In
The Function Specification of s o a p defines how s o a P is bound to use h t p for object communication.

Because s o a P uses x m l as the standard for information encapsulation and exchange
For use on the same platform, as long as different platforms support and can parse and process packets of s o a p.
Because s o a P is just a wire protocol that defines how to exchange data, it can use
Any standard communication protocol is used as a mechanism for physical communication. In the Function Specification of s o a p, select
As the first physical communication protocol, the h t p Communication Protocol is encapsulated by s o a P.
To communicate in packets containing h t p.

In addition to the h t p, software vendors can also implement other communication protocols to transmit s o a p
For example, a vendor of c o r B a can use I O P as an entity communication protocol. Of course, other
The communication protocol can also be used as the physical communication protocol of s o a p, for example, the next most promising
The communication protocol is s m t p.

Because s o a p chooses h t p as the first transport communication protocol
It is a standard communication protocol accepted by all platforms and operating systems.
Software developers of s o a P and h t p can easily integrate various platforms and implementation models, including
C o m/m t s/c o m +, c o r B a and e j B.

Different clients can use the s o a p standard call and
Use information provided by different backend platforms. For the client, you only need to use the s o a p
The standard allows remote service calls without knowing what technologies are used by the backend.

Currently, almost all implementation languages Support s o a P. For example, j a v a has class library,
C/C ++ has a function library, v B has MS soap to o l k I t, d e l p h I has s o a P Components and wizard, and so on. Because
Now software developers can use the s o a P technology to integrate heterogeneous platforms or develop distribution
Even so, software developers still face a very difficult problem,
That is, although the software developers of s o a P can encapsulate and exchange information, different implementation technologies
How can we call services provided by other implementation technologies?
This problem is the basis for initiating the idea of software services and is also a problem to be solved by Web Services.

Although c o r B A is designed to solve the problem of integration heterogeneity
Platform Component Technology, but when c o r B A wants to integrate other component models, such
C o m/c o m +, also need a variety of B r I d G E technology to help. For example, c o r B A-And com Bridge
.
However, these B r I d G E technologies are generally implemented on a specific component vendor, and they also limit the use
Users must use specific component model versions. In addition, the B r I d G E Software is usually a specific vendor.
Chapter 7 concepts of s o a P and web serv I c e use 7 download
Exclusive technology is not an open standard. For these reasons, we need to use B r I d G E Technology
Technique is very difficult and impractical in the I n t e r n e t/I n t r a n e t multivariate application environment.

Basically, the concept of Web Service is to use a standard output interface to define the implementation program generation.
Code, so that the outside world can be called through this standard output interface.
The standard output interface is w s d l (Web Service Description Language ).

W s d l is a file composed of x m L, which describes
Provides the function prototype, that is, various information such as the name and parameters of the function that can be called. In
After the current program code provides w s d l, the client can use w s d l to call and implement program generation
Code Service

Since the implementation program code provides w s d l, it can accept external calls, so the real
The current program code does not distinguish between client calls or other backend implementation program code calls.
As long as it is called through w s d l, the implementation of program code can provide its service

The client encapsulates the requirement information through s o a P and transmits it to the backend server through I n t e r n e t/I n t r a n e t
Chapter 2 Concepts of s o a P and web serv I c e use 9 download
And then call the backend functions through the Web service interface. Because s o a P is implemented in
Therefore, you can call any platform that supports h t p and can easily
Through the firewall, it is difficult to complete some component models that cannot be easily completed, such as D c o m.
Cross the firewall. After the server finishes processing the client request, it then uses s o a p to encapsulate the returned results,
Return to the client through I n t e r n e t/I n t r a n e t.

You only need to use
The technology of s o a P and Web Service can meet the requirements of distributed computing.
Specific Exclusive technologies are no longer limited by specific operating systems and platforms
Various implementation platforms on I n t e r n e t/I n t r a n e t.

Because I n t e r n e t/I n t r A N E T is a diversified computing
Environment is a combination of various implementation technologies, platforms, and operating systems. Therefore
It is necessary to combine the services provided by different implementation technologies on I n t e r n t/I n t r a n e t to form a set of network connections.
To build a computing environment, you must use standards accepted by everyone to integrate services with each other, s o a p
And Web services are standards generated under such requirements and quickly become accepted by everyone.
Open Standards.