查看Linux中內建的jdk ,設定JAVA_HOME

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在配置hadoop是，進行格式化hadoop的時候，出現找不到jdk 我用centos7是64位的, 發現本機有java ,就找了一下其位置找到了jdk-1.7.0_75which java[[email protected] hadoop-1.1.2]# which java/usr/bin/java[[email protected] hadoop-1.1.2]# ls /usr/bin/java/usr/bin/java[[email protected] hadoop-1.1.2]# ls -l /usr/bin/javalrwxrwxrwx. 1 root root 22 Jun 20 03:00 /usr/bin/java -> /etc/alternatives/java[[email protected] hadoop-1.1.2]# ls -l /etc/alternatives/javalrwxrwxrwx. 1 root root 39 Jun 20 03:00 /etc/alternatives/java -> /usr/lib/jvm/jre-1.7.0-openjdk.x86_64/bin/java         （可以看出檔案是link ，是個連結）[[email protected] hadoop-1.1.2]# ls -l /usr/lib/jvm/jre-1.7.0-openjdk.x86_64/bin/java-rwxr-xr-x. 1 root root 36548 Oct 25 2011 /usr/lib/jvm/jre-1.7.0-openjdk.x86_64/bin/java[[email protected] hadoop-1.1.2]# cd /usr/lib/jvm/jre-1.7.0-openjdk.x86_64[[email protected] jre-1.7.0-openjdk.x86_64]# lsbin lib 如此來，可以暫時的斷定是  /usr/lib/jvm/jre-1.7.0-openjdk.x86_64root使用者下改設定檔 ： vi  /etc/profile找到export PATH USER LOGNAME MAIL HOSTNAME HISTSIZE HISTCONTROL在下面寫上：export JAVA_HOME=/usr/lib/jvm/jre-1.7.0-openjdk.x86_64export PATH=$PATH:$JAVA_HOME/binexport CLASSPATH=.:$JAVA_HOME/lib/tools.jar:$JAVA_HOME/lib/dt.jar :wq  儲存退出用echo $JAVA_HOME#更新jdkupdate-alternatives --install /usr/bin/java java /opt/jdk1.7.0_79/bin/java 300 update-alternatives --install /usr/bin/javac javac /opt/jdk1.7.0_79/bin/javac 300 update-alternatives --install /usr/bin/jar jar /opt/jdk1.7.0_79/bin/jar 300update-alternatives --config java選擇帶有jdk1.7.0_79 的選項即可以了

 

查看Linux中內建的jdk ,設定JAVA_HOME