安装 Java

https://download.oracle.com/otn/java/jdk/7u79-b15/jdk-7u79-linux-x64.rpm?AuthParam=1570520283_892072526df12048e37126b6f9cc6cdf

2.如果有安装openjdk 则卸载

[root@localhost ~]# rpm -e  ` rpm -qa | grep java`

3.安装java rpm

 rpm -ivh jdk-7u79-linux-x64.rpm

4.配置/etc/profile

#java
export JAVA_HOME=/usr/java/default
export PATH=$JAVA_HOME/bin:$PATH
export CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar

5.source /etc/profile

Java 的tar包解压后，直接配置环境变量即可。

tar xvf java.tar -C /home

export JAVA_HOME=/home/jdk
export PATH=$JAVA_HOME/bin:$PATH