The nature of HTTP messages
Let's examine the format of an HTTP message. Messages are either a request message sent from a client to a server, or a response message sent from a server to a client. Based on an understanding of the format, we will show you how Java supports these messages. HTTP messages are, for the most part, readable by humans. Both the request and response messages use this structure:
A line indicating the type of message
Zero or more header lines
A blank line
An optional message body containing data
The following is an example of an HTTP request:
GET /index HTTP/1.0
User-Agent: Mozilla/5.0
A client request message consists of an initial request line and zero or more header lines. A response message consists of an initial response line (called the status line), zero or more header lines, and an optional message body.
Let's examine these elements in more detail.
Initial request line format
The formats of the request and response initial lines differ. The request line consists of...
