安装命令
下载：
# cd /opt/
# wget --no-cookies --no-check-certificate --header "Cookie: gpw_e24=http%3A%2F%2Fwww.oracle.com%2F; oraclelicense=accept-securebackup-cookie" "http://download.oracle.com/otn-pub/java/jdk/7u79-b15/jdk-7u79-linux-i586.tar.gz"
# tar xzf jdk-7u79-linux-i586.tar.gz
修改默认命令位置：
# cd /opt/jdk1.7.0_79/
# alternatives --install /usr/bin/java java /opt/jdk1.7.0_79/bin/java 2
# alternatives --config java
验证是否安装成功
# java -version
