From Ole to SOA, SOA is actually very simple!

A San saw a very interesting webpage and wanted to save it. So she clicked "file-> Save as" and chose "webpage, all (*. htm ,*. html )".

OK ,a three hard disks have an a.html file and a folder A, which stores all the resources, images, CSS, and JS on the webpage.

A san looked at the large number of files and wanted to sort them out. So a San called axman. "eldest brother, can I save the current webpage as a file and display it again?

What is the original effect? "

Axman was dizzy for a long time and didn't dare to say anything. I thought someone could be stupid in this world, but I didn't dare to say it because axman owed a total of tens of thousands of dollars, so

A San's dumb, axman will answer him right away when there is a problem, so axman's cool voice from the original ancient glacier sounded at the other end of the phone:

"A San, you should like this, file-> Save As, select Web file, single file (*. MHT), then it will be saved as a composite document ".

"Ah, big brother, this is the case. Is a composite document compressed by multiple formats? "

"Yes. In this way, the composite document can be decomposed and re-displayed by the browser ".

"Ah, I know, the same is true for word ".

"Boom! ", When axman fainted, arousing heavy waves ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

"It's a structured document. You don't know what it means ."

On the side of the side, axman has been raising rackets for many years and keeps jumping. This guy is not very intelligent. After a few years, he has written a small program, and he is smart and studious.

Very curious, favored by axman.

I listened to the conversation between ahe and axman and asked curiously: "What is composite document, what is structured document "?

Axman changed his kind of tone and said slowly .......

A composite document is a document that separates multiple documents with the specified boundary. Different types of documents are visually encoded in a specific way in the boundary-separated area.

When the application interprets the composite document, it is restored to multiple documents based on Boundary and encoding rules and then interpreted by the same application.

However, a disadvantage of a composite document is that it cannot be opened by multiple applications at the same time, and is generally very writeable, because it is actually encoded and stored in text order,

Therefore, after an application loads the file into the memory, if other applications rewrite the content, the content accessed by the two applications will conflict.

In terms of storage models, structured documents are similar to directories. subdirectories and files can be contained in directories, and sub-storage and streams can be called in structured documents.

That is, different applications can access different parts of the same structured document at the same time, just as accessing files in different directories in the same file system will not cause any conflict.

I heard a lot of questions and asked: what is the relationship between it and the OLE you want to talk about?

The concept of structured documents will be followed by the emergence of OLE. On this basis, components, from local call to RPC to SOA, are created because of the solutions to structured documents.

The original intention. MS Office played an indelible role in this historical development.

First, a group of cool people in MS developed the MS Word. its functionality and ease of use suddenly kicked the WPS that has been popular in China for more than a decade out of the Emei Mountain.

You have climbed up. this batch of cool people not only have the technical skills but also have the concept of cool, which means that the level of WPS is comparable to that of shoes. while designing word, they also designed excel,

In office suites such as Powerpoint, the most important thing is that they have successfully solved function calls between each application in the suite.

For example, if you want to insert an Excel table into a Word document, the general idea is to copy the logic of the workbook to the word, that is, to explain that wrod must have an explanatory electron.

The functional code of the table. However, this is not the case for Ms users. Instead, the structured document function is used to save the workbook as a sub-storage in the DOC file, and what is stored in it?

The code of the application. In Windows, the csid can be used to find the application that explains the stream in the sub-storage from the registry. In this way, the structured document can be used.

Store content that can be processed by any other application.

In this way, the "component" with a single function is not called a component yet, but I will use the word "component" in advance because I do not know what it is currently called ), it can be repeated multiple times by other applications.

Allows a single component to form a system with complex functions. The Ms cool-man began to constantly call the models of other components by using the local call method to modify them into component services.

Model, that is, to publish a component with a function as a Service. Other applications need to call the function of the component by providing corresponding parameters to the System Service, and the application itself is fundamental.

You don't have to worry about what the sub-storage is stored and accessed, and how to handle it. What you need to do is to provide the basic access API environment for the component, that is, the basic input and output.

It can completely process the content specified by the application for processing.

Although Ole was finally developed into com, COM +, and remoting, it was initially designed to solve the mutual calling of functions in office suites. It has relatively complete functions and is stable and accessed for multiple times.

Is released as a service. With the protocol and control of service access, the component mode is changed.

The call boundary of the component model change function changes from the locall API call to the heterogeneous access. For example, if the operating system command implements a program, it can only be

The system commands are published as a service through the shell container, which can be called by a variety of programming languages that can be called by shell in the system.

This is actually a component service that weakens the model.

I can't help but clap my hands. That's great. It's so convenient for everyone.

Axman touched a lot of his head: "a lot, you are so kind, it is not as you think ."

This is the case in this world. Everything is relative. In human society, some people are a person, but once a specific name is given to them, for example, when they call them officials

It's not easy to provide the corresponding services.

"Component" is essentially code that completes some specific functions, but now it is upgraded to a component. to make it service, you must follow certain protocols, these Protocols define many interfaces for accessing components.

In the territory of MS, even the VIP members of the MS family, VC/Vb, who want to access these components, also need to use the iunknow and idispatch interfaces. In addition, they make the dizzy UUID ununderstandable.

Parameters and other complex relationships and procedures can make the "component" serve you. in the Java territory, you use complex EJB access protocols to make components serve you. the complexity is not what you can imagine. for example

I had to pay 480 yuan of vehicle and boat tax last time, but I had to request the service from the Tongzhou tax component at the cost of a day off (1500 oceans deducted) because the component was not working on weekends.

Later, the component callers were not happy. They gave comments to the "Organization" and demanded that the components providing functions should have a unified and convenient interface for calling. We only need to provide sufficient information to this interface, component

Services should be provided. These interfaces cannot be coupled with a specific environment and can accept the same requests from foreigners and local people of different types. therefore, "Organization" allows components to package themselves into Web Services.

Any caller sends a defined document through the HTTP link, and the component provides services. The organization finds that something called Soap can complete such communication, while different countries have different types

The caller is also happy to use this protocol, so everyone has adopted a unified web service model to request services. As for how the caller provides services, it is much more convenient.

 

SOA is not complex in nature. It is only a design concept of network-based component calling method, not a specific implementation technology. before that, many "Concepts" have implemented this function.

By adding the network function to the component, the call boundary can be extended from the same machine to the inter-machine call. This expands the shared scope of common functions in design. call the Updater with control over the call Protocol

This idea of "convenience for the people" not only facilitates callers, but also facilitates service providers. The same set of components can be released as web services for all users to access this

Web Server personnel provide services (this does not involve security discussions). From the perspective of "organizations", the efficiency of the Organization has been raised and received praise from callers, therefore, "organizations" promote this model to "serving the people"

The English name is "Soa ". we used to design a system focusing on functions and providing users with what they wanted. Now, we focus on services. We have many professional service teams released in multiple

On the server, access us when you need services. This is the essence of SOA.

Axman looked back and looked at it a lot. He was drooling and he was about to get down ......................

 

A few important words:

SOA is a design concept, and Web Service is a means of SOA Implementation (Meaning you can implement SOA without web service, as long as your architecture conforms to the SOA idea)

SOA is not a panacea. Not all system architectures are suitable for SOA, such as desktop application systems without remote calls and distributed applications. The only benefit of using SOA is to slow your system down.

SOA is a long-standing idea, but it has recently been packaged by some vendors, so it is an economic product rather than a technological product.