Javaweb Chapter 1 HTTP protocol

1. The difference between static Web and Dynamic Web:

The most essential difference between static Web and dynamic Web is that static Web is unable to perform database operations, while Dynamic Web is capable of database operation. The most important feature of dynamic web is interactivity, so-called interactivity is that the server will automatically display different results depending on the user request.

2, OSI Reference Model (from top to bottom): Application layer, presentation layer, session layer, Transport layer, network layer, data link layer, physical layer.

3, HTTP (hypertext Transfer Protocol) Hypertext Transfer Protocol, is a distributed, cooperative, multimedia information System services, application-oriented protocols. Is the most widely used application layer protocol on the Internet, it communicates based on the TCP protocol of the Transport Layer, and the HTTP protocol is a general and stateless protocol.

4. TCP/IP four Layer model: application layer, Transport layer, internetwork layer, network interface layer. TCP belongs to the transport layer, and IP belongs to the internetwork layer.

5, the main features of the HTTP protocol: Follow the request/response model (support client/server mode), no connection (limit each connection to only one request, the server after processing the client's request, and received the customer's answer, that is, disconnected), stateless (no memory capacity for transaction processing, The state for the last connection transfer was not saved, and if subsequent processing requires the previous information to be retransmitted, it is simple, fast, and flexible (any type of data can be transmitted).

6. HTTP protocol request: Request line, request header, blank line, message body;

HTTP protocol response: Status line, response header, blank line, message body;

7, Request method: Get,pose,head,put,delete,options,trace,connect.

Request Line: Request method, URL of the request (Uniform Resource location), HTTP version (1.1);

Status line: HTTP version, response status code, response description.

Response Header: Encoding method, Content type

8, dynamic Page technology: CGI technology (Common Gateway Interface Public Gateway interface can be implemented in multiple languages), PHP technology (hypertext Preprocessor Hypertext preprocessing), Microsoft ASP (Active Server Pages Dynamic Services page), ASP. NET, Java-based servlet/jsp technology (Java Server pages)

9, CGI defects: each request to open a CGI process, serious consumption of server resources, greatly restricting a server can support the number of concurrent CGI users;

PHP for personal and small project development;

Asp. NET suitable for medium-sized project development;

JSP suitable for medium and large project development, enterprise-level architecture development.

10. Web container: Responsible for managing and running Servlets.

Container support for Servlets:

• Communication support (encapsulating the request information and the corresponding information into the request object and the Response object)
• Servlet lifecycle management (generating and destroying servlets and invoking servlet-related methods)
• Multithreading support (thread creation, thread start, thread run, thread synchronization)
• JSP support
• Handle security.

11. The servlet specification defines only the standard functionality that a container must implement.

12, Server.xml and Web. Xml are the main configuration files for Tomcat.

Javaweb Chapter 1 HTTP protocol