ubuntu设置java环境

·用文本编辑器打开/etc/profile
·在profile文件末尾加入：
export JAVA_HOME=/usr/lib/jdk1.6.0_45
export PATH=$JAVA_HOME/bin:$PATH
export CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar

sudo source /etc/profile

sudo update-alternatives  --install  /usr/bin/java java  /usr/lib/java1.6.0_45/bin/java 300

sudo update-alternatives  --install  /usr/bin/javac javac  /usr/lib/java1.6.0_45/bin/javac 300

sudo update-alternatives  --install  /usr/bin/javah javah  /usr/lib/java1.6.0_45/bin/javah 300

sudo update-alternatives  --install  /usr/bin/jar jar  /usr/lib/java1.6.0_45/bin/jar 300

sudo update-alternatives  --install  /usr/bin/javap javap  /usr/lib/java1.6.0_45/bin/javap 300

sudo update-alternatives  --install  /usr/bin/javaws javaws  /usr/lib/java1.6.0_45/bin/javaws 300