jsp中如何清除缓存（转）

1. <%      
2. response.setHeader("Cache-Control","no-cache"); //HTTP 1.1      
3. response.setHeader("Pragma","no-cache"); //HTTP 1.0      
4. response.setDateHeader ("Expires", 0); //prevents caching at the proxy server      
5. %>  

一、清除页面缓存

1. 在jsp页里

   ? 1 2 3 4 <%response.setHeader( "Pragma" , "No-cache" ); response.setHeader( "Cache-Control" , "no-cache" ); response.setDateHeader( "Expires" , 0 ); response.flushBuffer();%>

   在html页里：

   ? 1 2 3 4 < meta http-equiv = "Content-Type" content = "text/html; charset=gb2312" > < META HTTP-EQUIV = "Pragma" CONTENT = "no-cache" > < META HTTP-EQUIV = "Cache-Control" CONTENT = "no-cache" > < META HTTP-EQUIV = "Expires" CONTENT = "0" >

   二、清除cookie

   ? 1 2 3 4 5 6 <%    Cookie killMyCookie = new Cookie( "mycookie" , null );    killMyCookie.setMaxAge( 0 );    killMyCookie.setPath( "/" );    response.addCookie(killMyCookie); %>

   三、清除session

   清除session方法

   ? 1 2 3 4 <%@ page language= "java" %> <% session.invalidate(); %>

   在页面关闭时清除session，需要捕获windows.onclose事件，再调用清除session方法

   补充：如何使用 JavaScript 代码清除缓存？

   如果在服务器级不能生成随机数，您可以使用 JavaScript 代码在客户端（浏览器）级生成一个字符串。以下示例图解说明如何使用标准图像代码或 Iframe/JavaScript 代码执行缓存清除。

   这些仅为示例。如果要使用该代码，请为特定 HTML 代码对示例作相应调整。您必须将实际代码粘贴到这些示例中的相应位置。

   标准图像代码示例：

   ? 1 2 3 4 5 6 7 8 9 10 11 <SCRIPT LANGUAGE= "JavaScript" > <!== hide from non-JavaScript browsers var axel = Math.random() + "" ; var num = axel * 1000000000000000000; document.writeln( ‘<A HREF="http://ad.doubleclick.net/jump/N409.somesite/B470;sz=468x60;ord=‘ + num + ‘?"><IMG SRC="http://img.558idc.com/uploadfile/allimg/210625/1541103c2-0.jpg + num + ‘?" BORDER=0 WIDTH=468 HEIGHT=60 ALT="Click Here!"> Click Here!</A>‘ ); // end hide from browsers ==> </SCRIPT> <NOSCRIPT> <A HREF= "http://ad.doubleclick.net/jump/N409.somesite/B470;sz=468x60;ord=[timestamp]?" > <IMG SRC= "http://ad.doubleclick.net/ad/N409.somesite/B470;sz=468x60;ord=[timestamp]?" BORDER=0 WIDTH=468 HEIGHT=60 ALT= "Click Here!" > Click Here!</A> </NOSCRIPT>

   Iframe/JavaScript 代码示例：

   ? 1 2 3 4 5 6 7 8 9 10 11 12 <SCRIPT LANGUAGE= "JavaScript" > <!== hide from non-JavaScript browsers var axel = Math.random() + "" ; var num = axel * 1000000000000000000; document.writeln( ‘<IFRAME SRC="http://img.558idc.com/uploadfile/allimg/210625/15411021Y-1.jpg + num + ‘?" WIDTH=470 HEIGHT=62 MARGINWIDTH=0 MARGINHEIGHT=0HSPACE=0 VSPACE=0 FRAMEBORDER=0 SCROLLING=no BORDERCOLOR="#000000">‘ ); document.writeln( ‘<SCR‘ + ‘IPT language="JavaScript1.1" SRC="http://img.558idc.com/uploadfile/allimg/210625/1541101202-2.jpg + num + ‘?"></SCR‘ + ‘IPT></IFRAME>‘ ); // end hide from browsers ==> </script> <noscript> <A HREF= "http://ad.doubleclick.net/jump/N409.somesite/B470;abr=!ie4;abr=!ie5;sz=468x60;ord=?" > <IMG SRC= "http://ad.doubleclick.net/ad/N409.somesite/B470;abr=!ie4;abr=!ie5;sz=468x60;ord=?" BORDER=0 WIDTH=468 HEIGHT=60 ALT= "Click Here!" > Click Here!</A> <noscript>