What should you learn first to learn JAVA WEB?

Recently, many children who have just started to learn Java Web development have asked the editor why they have to learn so much. It is necessary for us to take a look at what we have learned from a higher level, so today we will start. What you need to know before learning Java web development.

Introduction to the Internet Before starting the journey of Java Web development, let us first briefly understand the technical connotation and development history of the Internet (Internet)!

Entering the field of Java Web development means that you will join the Internet trend as a programmer. So looking at the Internet from a technical perspective, if you open the inside of the Internet, what would its internal structure look like?

The Internet refers to a network of computers connected to each other through the TCP/IP protocol suite. TCP is Transmission Control Protocol, Transmission Control Protocol; IP is Internet Protocol, Internet Protocol. The TCP/IP protocol suite is a network communication model and the infrastructure of current Internet communication.

IP is used to identify a computer on the network. For computers to be connected together to communicate with each other, they first need to know the target computer to connect to, and IP can identify a computer. To make an analogy, we also need to establish connections between people to communicate. When speaking in a group of people, first call out a person's name, and he will know that you are talking to him. IP is the name of the computer.

TCP is a protocol for controlling the transmission of information between computers. The same analogy is the language and method of communication between people. It is ineffective for a Chinese who does not know foreign languages ​​to communicate with an American, just like a computer sending data packets that the target computer cannot recognize. The ability to identify computers on a network and also communicate in a mutually understandable manner so computers can be connected together.

The technical connotation of the Web

The World Wide Web was originally played by a group of scientists, who hoped to transmit experimental data through the Internet. Therefore, a complete technical system for describing information, positioning information and transmitting information was invented.

How to understand the technical connotation of the World Wide Web? First of all, it runs on the Internet. It is an application protocol based on the TCP/IP protocol. It is a super-large-scale distributed system formed by hypertext documents linked to each other.

You need to understand three terms here: HTTP Hypertext Transfer Protocol, HTML Hypertext Language and URL Uniform Resource Locator Service. Although it is a technical term, we can see traces of them in our daily use of the Internet.

You often hear about HTML5 today, such as WeChat’s HTML5 page, HTML5 games, etc. HTML started with version 1.0. There is a standardization organization called W3C, which is gradually maintaining such a set of HTML language standards and has evolved to today's HTML5. The role of HTML is to describe hypertext documents. For example, if we want to display something to users, we need to express it in HTML so that we can put it on the World Wide Web for others to browse.

URL can be understood as a website address, which is a string we enter in the browser. It is used to locate hypertext documents. The URL protocol defines how to identify a web page on the Web, that is, a hypertext document. This is similar to how the IP protocol identifies a computer.

When we enter the URL in the browser, we will see that there is "http" in front of the URL, which refers to an HTTP protocol. The HTTP protocol defines how to interact with hypertext. The information is described through the hypertext document and can be located. Next, it needs to be accessed through the HTTP protocol. The HTTP protocol defines a set of tasks for interacting with web pages. We will not go into details for the time being. We only need to know that this is a protocol for obtaining information. The browser will translate our various actions into HTTP protocol-related actions for processing with the Web server. Interactively, and renders the resulting hypertext document into readable content for easy browsing. What we call "connections" are, at the technical level, these protocols quietly playing the role of infrastructure. This is the basic principle of the Web.

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