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Oracle JDBC????????????

?Linux??????Oracle JDBC??????????????????????????????????entropy pool??????????????????????????

????

?Oracle JDBC???????????????connection reset exception?????????????????? JDBC?????????????????????????????????Linux????????????/dev/random?/dev/urandom???????????

????

??????????? JDBC ?????????????????????????????????????????????? JDBC ???????????????????????????

• ????????????????????
• /dev/random?????????????????
• JDBC ????/dev/urandom?????????????????????

????

????Oracle JDBC?????????????????????

1. ????????

?????????????????????????????????

cat /proc/sys/kernel/random/entropy_avail

?????????0???????????????????????????????????????????????

2. ??rngd??????

rngd ??????????/dev/random??????????rngd??????????????????????????

??????rngd??

sudo apt-get install rngd

??????rngd??

??/etc/sysconfig/rngd??????????

# echo 'EXTRAOPTIONS="--rng-device /dev/urandom"' > /etc/sysconfig/rngd

??????rngd??

# service rngd start

??????rngd??

# chkconfig rngd on

????????rngd???????/dev/urandom????????????????????

3. ??????????

???????????????????????????????

dd if=/dev/random of=rnd_file bs=1 count=64

??????????????????????64 bytes????64+0????????????????

4. ??java.util.Random??????

???????JDBC ?????????/dev/urandom??????????????java.security.egd?????????????????

-Djava.security.egd=file:///dev/urandom

????????JDBC ?????????java.util.Random ??/dev/urandom?????????

5.??????

????????????????????????????????

for i in {1..100000}; do cat /proc/sys/kernel/random/entropy_avail; done

???????????0?????????????rngd?????????????????????????

?????

????????????????????Oracle JDBC?????????????????????????????????????

• ????????????????
• ??JDBC ???????????
• ???????????????????????

???????????????Oracle JDBC???Linux?????????????????????????????