?????????鱳??
??????????????????“???????????????д??????”??java??????????д???????Ч?????????????????????????????????????????????????????????????????????????????????buffer??????buffer??
??????????????
???????????????????????????д??Ч?????????????????????д?????Ч???????
??????????????
??????????????????????????????????????????????ε????????????????????????????????????????????????cpu?????????????????и??????д?????Ч??????
?????????黷??
????OS: windows 7 64bit
????cpu: 4core?? ?????2.4GHZ
????mem??6G
????jdk version??Java HotSpot(TM) 64-Bit ??1.8.0_101
?????塢??鰈??
???????????8???????飬??????????????С???10M??50M??100M??200M??500M??800M??1G??2G??
???????????????????????????????????
?????????????
??????1??java???????д????Ч???????????????

??????1??java???????д????Ч????????????????????????

??????2??java???????д????Ч??????????????????????????

?????2???????С?2048m???????д???????????cpu????????

?????3???????С?2048m???????д???????????jvm?????????

?????4???????С?2048m???????д??????????????????????????

????????к?????‘FileChannel’????μ????????????????
?????????????
????1?????????????д?????????С???????????FileChannel<BufferedOutputStream<FileOutputStream<BufferedWriter<FileWriter;???1???1?????????????ù?????С???д??????￡??????????2?????????
????2????????????Сд???????У???????????buffer???????????/?????????????buffer??????Ч??????
????3??????д?????jvm cpu??????????????????????2???3?????????
????4????????????С??( fileSize >=1.5G )??FileChannel??????ú?????????????1??????????????????????????????????д???????С???????4????????????????FileChannel???MappedByteBufferд?????buffer??direct buffer???????????????д????????????????????????
????5??С???д???????￡?1M???????FileChannel??Щ???С?????Ч???????????????Ч????
???????????????????????м??????t??飺
????1??С???????M???????д???????ó????io?????У????????BufferedInportStream????б?????nio??FileChannel??
????2?????????fileSize > 1G???????????????????????廷???????????д????????FileChannel???С???????????????????д??Ч????￡??????????÷??д???????TODO????????????????
????3???????????￡????Ч????????????????????FileChannelд???????
???????demo
?????ο?git???https://github.com/daoqidelv/io-demo