mac上切换jdk版本

vi /etc/profile

alias setJdk6='export JAVA_HOME=$(/usr/libexec/java_home -v 1.6)'
alias setJdk7='export JAVA_HOME=$(/usr/libexec/java_home -v 1.7)'
alias setJdk8='export JAVA_HOME=$(/usr/libexec/java_home -v 1.8)'

setJdk7

java -version