Linux安装jdk8及环境变量配置

https://www.jianshu.com/p/f000e05f3512

脚本：

 1 #!/bin/bash
 2 # install jdk and configuring environment variables
 3 function installjdk(){
 4 tar -zxf jdk-8u201-linux-x64.tar.gz -C /usr/local
 5 cat >> /etc/profile << EOF
 6 export JAVA_HOME=/usr/local/jdk1.8.0_201
 7 export PATH=\$PATH:\$JAVA_HOME/bin
 8 export CLASSPATH=.:\$JAVA_HOME/lib/dt.jar:\$JAVA_HOME/lib/tools.jar
 9 EOF
10 }
11 
12 #-------------------------- testing jdk--------------------------
13 echo "========= Start to install JDK =============="
14 source /etc/profile
15 if [ -n "$JAVA_HOME" ];then
16 echo "JDK already installed"
17 java -version
18 else
19 if [ -f "./jdk-8u201-linux-x64.tar.gz" ];then
20   installjdk
21   source /etc/profile
22   java -version
23   echo "use the 'source /etc/profile' command to update local variables"
24 else
25   echo "Missing 'jdk-8u201-linux-x64.tar.gz' file in statistical catalogue"
26   echo "Failed to install JDK"
27 fi
28 fi
29 echo "========= End installation of JDK ==========="