Response and request base of Javaweb

1 Response

A Send error response

. Senterror ()///with one parameter and 2 parameters

b Setting the response header

. SetHeader (String name,string value)//There are several more, here only one

Response Redirection: 302 procedure?

//         302The first one//        response.setstatus (302); //         response.setheader ("Location", Request.getcontextpath () + "/index.jsp"); //         302 The  Second          response.sendredirect ("/pra/index.jsp");

The response is timed to refresh the specified page (equivalent to timed redirection):

//         regularly updated            response.setheader ("Refresh", "5;url=" +request.getcontextpath () + "/index.jsp");

Byte stream/character stream of C-response body

D Request's Domain attribute its with session and application is called the three domains, each domain has its own setattribute () getattribute () RemoveAttribute () method

E-Response encoding

Server to set setcharacterencording ("Utf-8") and setContentType ("Text/html;characster=utf-8") when sending

This allows the browser (client) to be acquired before it is properly encoded

2 Request

A Get Ip/request method/browser type (identify user)/refer anti-theft chain

//         get the hostname and other things //        System.out.println (request.getremoteaddr ()); //         System.out.println (Request.getmethod ()); //         System.out.println (request.getlocaladdr ()); //         System.out.println (Request.getheader ("user-agent")); //         System.out.println (Request.getheader ("Refer"));

b How to get URLs

C Request parameters can be obtained regardless of whether get or post

Get: Parameter after URL

http://localhost:8080/pra/Aservlet?one=123&two=3213//Parameters and URLs used? Connection, between parameters with & connection, parameter name and value = Connection

Post: The parameter is in the request body

D forward/include Request forwarding process?

Forward: Only the header information of the previous servlet is retained, not the body, the first request body cannot be too large

Includ: Retains the header of the previous servlet and retains its body

Forwark/include and redirect relationships?

Redirect: Servlet may be changed in different requests (request and response)

Forward/include: Requests and response objects do not change in the same request

F Request Encoding

? When submitting a form on a page, if your page is of type utf-8, then the parameter you pass is the Utf-8 type.

? Post request: setcharacterencording ("Utf-8") and setContentType ("Text/html;characster=utf-8")

? GET Request: We use the Java string to do it ourselves.

　　　　

　　　　

　　

　　　　

Javaweb Response and Request Basics