Simple is Best

some php and jsp page must be cached in squid to increase the response speed and decrease the j2ee or apache thread number.
using refresh_patterns solved it.
refresh_pattern -i .jsp 720 25% 1440 override-expire ignore-reload
refresh_pattern -i .php 720 20% 1440 override-expire ignore-reload
ignore-reload will prevent request no-cache etc,like ctrl+F5 under ie will refresh the squid cache,but ignore-reload will prevent it.
ATT:
squid default squid.conf include refresh_pattern -i .js 360 25% 1440, the above -i .jsp must stay top before this.else -i .js will be suit for the parsing.