What is a Web service?

First, the concept of WEB service

To understand a Web service, you must first understand what a service is.

Traditionally, we have provided the function of the computer daemon (Daemon), called the service. For example, let an anti-virus software run in the background, it will automatically monitor the system, then this automatic monitoring is a "service." In layman's words, "service" is a function that a computer can provide.

Depending on the source, the service can be divided into two types: Local Service (using the same machine service, no network), and "Network Service" (a service provided by another computer, which must be done over the network).

For example, I now have a bunch of pictures that need to be scaled down by half. So, we can think of "scaling pictures" as a service. You can use the "Local Service", the software on your own computer to reduce the image, you can also use the "Network Service" to upload pictures to a website, let the server for you to reduce the image, complete and then send back to you via the network. It's like, one thing you can do it yourself, or you can give it to another person to do it. Hungry, you can cook your own meals, you can also call to order a pizza, let the store for you to do a good job.

The essence of the Web service is to invoke the resources of other sites over the network.

Second, the WEB service architecture and the cloud

If the main part of a software uses "network Services", that is, it "outsourced" storage or computing links to other sites, then we say that this software belongs to the Web service architecture.

The basic idea of WEB service architecture is to give the non-core function to others to do it, and develop the core function. For example, if you want to develop a photo album software, you can fully use Flickr Web services, the photos are stored on it, you just do your best to do the album itself. On the whole, the function that does not belong to your core competence should be "outsourced".

The recent "Cloud computing" or "cloud service", which is a very red one, is actually synonymous with Web service, but more visually. They do not say you give things to other computers to do, and that you give things to the "cloud" to do.

Iii. Deficiencies in local services

"Network Services" is the future trend of software development and use, local services will be used less and more, mainly because of the following three reasons:

* Insufficient local resources. A lot of data and information are not available locally, only to other websites.

* Cost factor. Local services are often not economical, and services using professional websites are cheaper. This involves two parts of hardware and personnel, even if you can afford to buy hardware, to find a person to manage the system, it is also very troublesome.

* Portability is poor. If you want to transfer the services of this machine to other machines, it is often difficult, especially in the case of cross-platform.

What is a Web service?