Look at the HTTP protocol and Response setting response message

HTTP protocol

1. Request message: the data sent by the client to the server. Data
(1) Request line
(2) Request header
(3) Request blank line
(4) Request body
2. Response message:
Data format sent by the server to the client :
(1) Response line
Composition: protocol/version response status code status code description
Response status code: the server tells the client browser that this request and a response
status code is 3 digits
1xx: the server receives the client message, But the reception has not been completed. After waiting for a period of time, the 1xx multiple status code
2xx: success is sent . Representative: 200
3xx: Redirect. Representative: 302 (resource redirection) 304 (access cache)
4xx: client error. Representative: 404 (the request path does not have a corresponding resource) 405 (the request method does not correspond to the doXxx method)
5xx: server-side error. Representative: 500 (an exception occurred inside the server)
(2) Response header
format: header name: value
Common response headers:
Content-Type: The server tells the client the data format and encoding format of the response body
Content-disposition: The server tells the client to What format to open the response body data
Value: in-line default value, open
attachment on the current page ; filename=xxx Open the response body as an attachment. Download Document

(3) Response blank line
(4) Response body: transmitted data

		HTTP/1.1 200 OK
		Content-Type: text/html;charset=UTF-8
		Content-Length: 101
		Date: Wed, 06 Jun 2018 07:08:42 GMT

		  hello , response

Response object

1. Set the response line
Format: HTTP/1.1 200 ok
Set the status code: setStatus(int sc)
2. Set the response header: setHeader(String name, String value)

3. Set the response body:

  1. Get output stream
    Character output stream: PrintWriter getWriter()
    Byte output stream:ServletOutputStream getOutputStream()

  2. Use the output stream to output data to the client browser

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Origin blog.csdn.net/qq_42524288/article/details/104892010