Configure jdk environment in CentOS7.4

1. Download jdk

　　First create the installation package placement location

　　　　mkdir -p /usr/local/java

　　Then you can download it directly through wget + url, or you can download it to the windows system first and then upload it through xshell or ftp. Note that the download of oracle needs to be logged in first. Here is the download address of jdk8

2. Unzip the compressed package

　　tar -zxvf jdk-8u171-linux-x64.tar.gz

　　After decompression, the directory is jdk1.8.0_171

3. Configure environment variables

　　vi /etc/profile

　　Add the following configuration at the end of the file:

　　export JAVA_HOME=/usr/local/java/jdk1.8.0_171


　　export CLASSPATH=.:$JAVA_HOME/jre/lib/rt.jar:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar 　　

　　export PATH=$PATH:$JAVA_HOME/bin

4. Check if the installation is successful

　　java -version

　　The version information table name appears, the installation is successful