jdk安装

检查和删除系统预装jdk

#如果操作系统不是最小安装，会默认安装openjdk

$ rpm -qa | grep java

python-javapackages-3.4.1-11.el7.noarch

java-1.8.0-openjdk-1.8.0.171-8.b10.el7_5.x86_64

tzdata-java-2018e-3.el7.noarch

javapackages-tools-3.4.1-11.el7.noarch

java-1.8.0-openjdk-headless-1.8.0.171-8.b10.el7_5.x86_64

 

#删除系统预装jdk，可以一条命令直接删除

$ rpm -e --nodeps `rpm -qa | grep java`

 

#输入java -version测试，提示bash: java: command not found表面openjdk已经删除

$ java -version

-bash: java: 未找到命令

 

#下载jdk，然后解压

$ wget https://download.oracle.com/otn-pub/java/jdk/8u201-b09/42970487e3af4f5aa5bca3f542482c60/jdk-8u201-linux-x64.tar.gz

 

#解压到/usr/local/java

$ tar -zxvf jdk-8u201-linux-x64.tar.gz -C /usr/local/java

#执行命令后报错如下：

gzip: stdin: not in gzip format

tar: Child returned status 1

tar: Error is not recoverable: exiting now

#解决:使用以下命令重新下载后再解压

$ wget --no-check-certificate --no-cookies --header "Cookie: oraclelicense=accept-securebackup-cookie" https://download.oracle.com/otn-pub/java/jdk/8u201-b09/42970487e3af4f5aa5bca3f542482c60/jdk-8u201-linux-x64.tar.gz

 

#配置环境变量

$ vim /etc/profile

export JAVA_HOME=/home/soft/jdk1.8.0_111 

export JRE_HOME=${JAVA_HOME}/jre

export CLASSPATH=.:${JAVA_HOME}/lib:${JRE_HOME}/lib

export PATH=${JAVA_HOME}/bin:$PATH