安装 jdk 没什么好说的，写这个主要是为了以后方便直接复制命令执行，省得写或者找了
tar xvf jdk-8u102-linux-x64.tar.gz
vi /etc/profile
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export JAVA_HOME=/var/java/jdk1.8.0_102
export JRE_HOME=/var/java/jdk1.8.0_102/jre
export PATH=$PATH:/var/java/jdk1.8.0_102/bin
export CLASSPATH=./:/var/java/jdk1.8.0_102/lib:/var/java/jdk1.8.0_102/jre/lib
.
.
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reboot
#检查
java -version
22
vi .bashrc
JAVA_HOME=/var/java/jdk1.8.0_144
PATH=$JAVA_HOME/bin:$PATH
CLASSPATH=.:$JAVA_HOME/lib/tools.jar:$JAVA_HOME/lib/dt.jar
export JAVA_HOME
export PATH
export CLASSPATH
...
source .bashrc----------------------------------------------------------
rpm -qa|grep java
卸载openjdk
rpm -e --nodeps
echo -e "export JAVA_HOME=/usr/local/java/jdk1.8.0_144\n\
export JRE_HOME=/usr/local/java/jdk1.8.0_144/jre\n\
export PATH=\$PATH:/usr/local/java/jdk1.8.0_144/bin\n\
export CLASSPATH=./:/usr/local/java/jdk1.8.0_144/lib:/usr/local/java/jdk1.8.0_144/jre/lib" >> /etc/profile.d/java.sh
source /etc/profile
