设立页面不缓存

<metahttp-equiv="pragma"content="no-cache"> 

<metahttp-equiv="cache-control"content="no-cache,must-revalidate"> 

<metahttp-equiv="expires"content="0"> 

response.addHeader("pragma", "no-cache"); 

response.addHeader("cache-control", "no-cache,must-revalidate"); 

response.addHeader("expires", "0");