JSP database Interaction Object

Jspthe built-in object is in writingJSPObject that can be used directly without any claims Common built-in objects Out,request,response, session,application the Out object is used to output data to the browser The request object obtains relevant data from requests and browser-related information, which fails at the end of a page jump or request common methods for Request objects: String Getrequestparameter (string name) Gets the page submission data based on the name in the page form String Getrequestparametervalues (string name) gets a set of form components with the same name to submit data Void setcharacterencoding (String character) Specifies the encoding of the request Requsetdispatcher getrequsetdispatcher (String path) for forwarding requests The Response object is used to set the response parameters and get the response flow, etc. Void Addcookie (Cookie cookie) adds a cookie to the client Void setcontenttype (String type) sets the contentType type of HTTP Void setcharacterencoding (String type) sets the type of character encoding taken by the response Void Sendredirect (String location) to relocate the request to a new URL What is the difference between forwarding and redirection? Difference 1: URL changes on the browser when redirected Forwarding is the same as the URL on the browser Difference 2: Redirect actually produces two requests Forward only one request Redirect: send a request --The server runs a response request, returns a new address and response code to the browser, and the browser responds to the response code, determines that the response is redirected, automatically sends a new request to the server, and the request address is the address that was returned before-- The server runs and responds to requests to the browser Forward: send a request --The server runs--make the requested reset, for example via Request.setattribute (Name,value)--based on the forwarded address, get the address of the page-- Responding to a request to a browser Difference 3: The URL of the redirect can be any URL The URL to be forwarded must be the URL of this site Session Object A conversation is a series of related interactions between a user and a Web server over a period of time. It can contain multiple requests between the browser and the server. Response process. Common methods for session objects String getId () gets the ID Void setmaxinactiveinterval (int interval) Set session inactivity time Int Getmaxinactiveinterval () Gets the session active inactivity time (in seconds) void invalidate () Setting session object invalidation Void SetAttribute (String Key,object object) saved to the session object with key-value pairs Object GetAttribute (String key) Gets the objects in session by key Void removeattribute (String key) removes the specified key corresponding object from the Session object Expiration of Session one is the session timeout the other is to manually call the method setting to fail 1. Setmaxinactiveinterval () setting through the session object <% Seesion.setattribute ("admin", "admin"); Session.setmaxinactiveinterval (600); Response.sendredirect ("admin.jsp"); %> 2. Set up the code in the Project Web. xml <session-config> <session-timeout>10</session-timeout> </session-config> 3. in the application server settings, locate the <session-config> element in the Tomcat directory/conf/web.xml, where 30 of the <session-timeout> element is the default time, Unit minutes. The include directive indicates that inserting a text or code file during JSP compilation is static syntax <% @include file= "application file path

JSP database Interaction Object