1. 复制jdk到 /usr/local/java
cp jdk-8u40-linux-x64.gz /usr/local/java
2. 解压缩
tar xvf jdk-8u40-linux-x64.gz
3. 增加环境变量
vi /etc/profile
在最下面加入以下内容
export JAVA_HOME=/usr/local/java/jdk1.8.0_40
export JRE_HOME=/usr/local/java/jdk1.8.0_40/jre
export PATH=$PATH:/usr/local/java/jdk1.8.0_40/bin
export CLASSPATH=./:/usr/local/java/jdk1.8.0_40/lib:/usr/local/java/jdk1.8.0_40/jre/lib
4.测试
java -version
source /etc/profile