Shulou(Shulou.com)06/01 Report--

This article mainly explains "how to write a Tomcat by hand". Friends who are interested might as well take a look. The method introduced in this paper is simple, fast and practical. Let's let the editor take you to learn how to write a Tomcat by hand.

First, provide Socket services

The startup of Tomcat must be a Socket service, but it supports the HTTP protocol!

In fact, we can expand to think, since Tomcat is based on Socket, then it is based on BIO or NIO or AIO?

Second, the distribution of the request

To know that a Tomcat can serve multiple Web applications, it is obvious that Tomcat can send URL to different Web applications.

Third, the request and response need to be encapsulated as request / response

We are in the Web application layer, but we have never encapsulated request/response, we all use it directly, this is because Tomcat has been done for you!

Without saying much, let's take a look at the screenshot of the project first.

First, encapsulate the request object

Here, you can clearly see that we parse the HTTP protocol through the input stream and get the method of the HTTP request header and the URL.

Encapsulating the response object

Output and write based on the format of HTTP protocol.

Third, Servlet request processing base class

It was said earlier that Tomcat is a container that meets the Servlet specification, so naturally Tomcat needs to provide API. Here you see the common doGet/doPost/service methods of Servlet.

4. Servlet implementation class

Provide these two specific Servlet implementations only for subsequent testing!

V. Servlet configuration

You must feel something, don't you?

In servlet development, we use and in web.xml to specify which URL is handed over to which servlet for processing. To understand Tomcat, I suggest you take a look at this article, "detailed explanation of Tomcat's Server file configuration!" ". In the Java technology stack Wechat official account reply: tomcat, you can get more tomcat tutorials.

VI. Startup class

Here, you can see the Tomcat processing flow, that is, forming the Servlet relationship handled by the URL, parsing the HTTP protocol, encapsulating the request / response object, and instantiating the specific Servlet using reflection for processing.

VII. Testing

At this point, I believe you have a deeper understanding of "how to write a Tomcat by hand". You might as well do it in practice. Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.