The difference between nginx tomcat apache

Apache should refer to a project under the Apache Software Foundation - the Apache HTTP Server Project;

Nginx is also a Open source HTTP server software (of course it can also be used as a mail proxy server or a general TCP proxy server).

HTTP server is essentially an application - it usually runs on the server, binds the server's IP address and listens to a certain tcp port to receive and process HTTP requests, so that the client (usually Browsers such as IE, Firefox, and Chrome) can obtain web pages (HTML format), documents (PDF format), audio (MP4 format), videos (MOV format) and other resources on the server through the HTTP protocol.

Apache Tomcat is another project under the Apache Foundation. Compared with Apache HTTP Server, Tomcat can dynamically generate resources and return them to the client.

Both Apache HTTP Server and Nginx can return the content of a certain text file to the client through the HTTP protocol, but the content of this text file is fixed-that is to say, no matter how When anyone accesses it, the content they get is exactly the same. We call such resources static resources.

Dynamic resources are on the contrary, the content accessed by different clients at different times is different.

For example: a page that contains the current time and a page that displays the current IP address. Apache HTTP Server and Nginx themselves do not support generating dynamic pages, but they can be supported through other modules (such as through Shell, PHP, Python scripts to dynamically generate content).

If you want to use Java programs to dynamically generate resource content, it is difficult to do so using this type of HTTP server.

Java Servlet technology and the derived Java Server Pages technology allow Java programs to also have the ability to process HTTP requests and return content (dynamically controlled by the program). Tomcat is the container that supports running Servlet/JSP applications ( Container);

Tomcat runs on JVM. Like the HTTP server, it binds the IP address and listens to the TCP port. It also includes the following accusations:

The life cycle of the management Servlet program will The URL is mapped to the specified Servlet for processing and the Servlet program cooperates with the Servlet program to process the HTTP request - generate an HttpServletResponse object based on the HTTP request and pass it to the Servlet for processing, and return the content generated by the HttpServletResponse object in the Servlet to the browser.

Although Tomcat can also be considered an HTTP server, it is usually still used together with Nginx:

(1) Separation of dynamic and static resources - distribution using Nginx's reverse proxy function Request: All requests for dynamic resources are handed over to Tomcat, while requests for static resources (such as pictures, videos, CSS, JavaScript files, etc.) are directly returned to the browser by Nginx, which can greatly reduce the pressure on Tomcat.

(2) Load balancing. When business pressure increases, one Tomcat instance may not be enough to handle it. At this time, multiple Tomcat instances can be started for horizontal expansion, and the load balancing function of Nginx can Distributed to different instances for processing through algorithms

For more Nginx related technical articles, please visit the Nginx Usage Tutorial column to learn!

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