来源：http://www.cnblogs.com/xu-dong/p/6429301.html
1. 上传jdk7 和 jdk8 包
2. 解压
[root@localhost webapps]# tar -zxvf /package/jdk-7u80-linux-x64.tar.gz
3. 配置jdk变量
vi /etc/profile
export JAVA_HOME=/package/jdk1.7.0_80 export CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar export PATH=$PATH:$JAVA_HOME/bin
4. java -version
5. 给jdk1.7设置序列号
[xxx@localhost home]$ alternatives --install /usr/bin/java java /package/jdk1.7.0_80 3
6. 安装jdk1.8
[xxx@localhost home]$ alternatives --install /usr/bin/java java /package/jdk1.8.0_124 2
7.选择jdk对应的数字–切换jdk版本
[root@localhost ~]# java -version java version "1.7.0_80" Java(TM) SE Runtime Environment (build 1.7.0_80-b15) Java HotSpot(TM) 64-Bit Server VM (build 24.80-b11, mixed mode) [root@localhost ~]# alternatives --config java There are 3 programs which provide 'java'. Selection Command ----------------------------------------------- * 1 /package/jdk1.8.0_121/java 2 /package/jdk1.8.0_121/bin/java + 3 /package/jdk1.7.0_80/bin/java Enter to keep the current selection[+], or type selection number: 2 [root@localhost ~]# java -version java version "1.8.0_121" Java(TM) SE Runtime Environment (build 1.8.0_121-b13) Java HotSpot(TM) 64-Bit Server VM (build 25.121-b13, mixed mode)