????Windows ????? set ?????????????????????????????????????????Щ???????????????????????μ? autoexec.bat ????н?????????磺

????set JAVA_HOME=C:jdk

????set PATH=%JAVA_HOME%in;C:Windows;C:WindowsCommand

????set CLASSPATH=%JAVA_HOME%jrelib t.jar;.

??????Щ?汾?? Windows ?????? %??????% ???滻????????????????????????д C:jdk ?????? %JAVA_HOME% ???????C:Windows ?? C:WindowsCommand ?? Windows ?????????·???????????????????????????? autoexec.bat ??????????? PATH?????????? %JAVA_HOME%in ?????????? PATH ????????????????

????CLASSPATH ???????????????????????????·????????????????д???Щ????? C:java ?У?????? C:java ????? CLASSPATH ?????set CLASSPATH=%JAVA_HOME%jrelib t.jar;C:java;.??

????????? CLASSPATH ?а????????“????? (.)”???????????????????????????????????????????????? Java ?????????·????δ?????? CLASSPATH ????????????????????????????·???????? CLASSPATH ?У??? CLASSPATH ?е? “.” ???????????·?????磺

?????????? C:java ?????п????е??? HelloJava.class?????

C:> set CLASSPATH=C:jdkjrelib t.jar;. // ???? CLASSPATH ??????????????????? “.”
C:> cd java // ??? C:java ??
C:java> java HelloJava // ???? HelloJava
Hello?? Java. // ???н??
C:java> _
****

    ?? Linux ??????

????Linux ?????“??????=?????”?????????????? export ??????????????????????????ε??????????ú???Щ????????????? ~/.bash_profile ????? ~./bashrc ????????????

export JAVA_HOME=/usr/local/jdk
export PATH=$JAVA_HOME/bin:$PATH
export CLASSPATH=$JAVA_HOME/jre/lib/rt.jar:.

???????? PATH ???? $JAVA_HOME ????滻???? JAVA_HOME ????? $JAVA_HOME ????λ?á??????????? export PATH=/usr/local/jdk/bin:$PATH??????? $PATH ?????????????????????? PATH ??????????? PATH ???????????????????? PATH ?????????

????????? CLASSPATH ?а????????“????? (.)”???????????????????????????????????????????????? Java ?????????·????δ?????? CLASSPATH ????????????????????????????·???????? CLASSPATH ?У??? CLASSPATH ?е? “.” ???????????·????????

?????????? /home/fancy/java ?????п????е??? HelloJava.class?????

????[fancy@matrix fancy]$ export CLASSPATH=/usr/local/jdk/jre/lib/rt.jar:. // ???? CLASSPATH???????“.”

????[fancy@matrix fancy]$ cd ~/java // ??? /home/fancy/java

????[fancy@matrix java]$ pwd // ????????

????/home/fancy/java // ??????? /home/fancy/java

????[fancy@matrix java]$ java HelloJava // ???? HelloJava

????Hello?? Java // ???н??

????[fancy@matrix java]$ _