1. Tomcat server: If it is Tomcat with the installation board, only one version can be used, and several decompressed versions can be used.
Directory: bin: start-up related files
config: Support the relevant configuration files for Tomcat operation
lib: store jar files
Logs: log files
Temp: Temporary file
Webapps: Project stores temporary data
work: the project stores persistent data
2. Three-way handshake principle: a sends information to b, b returns information to a, and a and b establish a connection to start transferring files. For example: the client sends a request to the server, what is my name, I want to send you a file; the server receives it, and sends to the client what my address is and how much space is there; then the two establish a connection and start sending file.
3. Http request consists of four parts: request first line, request header, request blank line (separate request header and request body), request body.
4. Get and post requests:
(1) Both are ajax requests, ajax is a cross-domain request method based on the XMLHttpRequest object, and XMLHttpRequest is the core mechanism of ajax.
(2) The difference; post is more secure (will not be part of the URL, will not be saved in server logs and browser records), post request sends a larger amount of data (get has a length limit), post has a request body ( get does not), post can send many data types (get can only send ASCII characters), post is slower than get
5. Three ways to implement Servlet: 1) Inherit the Servlet interface 2) Inherit the GenericServlet class 3) Inherit the HttpServlet method
6. Http Same Origin Policy: Same protocol, same domain name, same port number.