The first chapter, the Deep Web request process
The b/S architecture brings 2 benefits.
1, the client uses a unified browser.
2, the service side based on unified HTTP.
1.1 b/S Network architecture overview
b/S network architecture has been simplified from front to back end, all based on Unified Application layer protocol HTTP to interact with the data, and most traditional CS Internet applications using long-connected interactive mode,
HTTP uses a non-stateful, short-link communication method, typically a single request completes a data interaction, usually a business logic, and then the communication connection is disconnected.
Reason: This way is to be able to serve more users at the same time, because the Internet user volume is large, it is not possible for each user access to keep this connection, or fry.
When a user enters a URL in the browser, a lot of things happen.
First, he will ask DNS to resolve the domain name to the corresponding IP address, and then based on the IP address on the Internet to find the corresponding server,
A GET request is made to this server, which decides to return the default data resource to the user who accessed it.
On the server side there is actually a very complex business logic: The service side may be a number of stations, in the end specify which servers to process the request, which requires a load balancing device to evenly distribute the user's request;
In-depth analysis of Java Web Technology Insider Reading notes-chapter I