一、Linux安装Java
1.查看本地是否已经安装 Java
# 如果没有则控制台不会有任何输出
[root@iZ7xv0ibz3fvihq4t7liz8Z opt]# rpm -qa | grep java
2.查看 Java 目录
[root@iZ7xv0ibz3fvihq4t7liz8Z etc]# which java
/usr/bin/java
3.删除 Java
删除所有 Java 相关包
yum -y remove *java*
删除 /etc/profile 文件下的相关 Java 环境配置
JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.362.b08-1.el7_9.x86_64/
JRE_HOME=$JAVA_HOME/jre
CLASS_PATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar:$JRE_HOME/lib
PATH=$PATH:$JAVA_HOME/bin:$JRE_HOME/bin
export JAVA_HOME JRE_HOME CLASS_PATH PATH
4.搜索本地 Java 版本
[root@iZ7xv0ibz3fvihq4t7liz8Z opt]# yum list | grep java-1.8.0
Repodata is over 2 weeks old. Install yum-cron? Or run: yum makecache fast
java-1.8.0-openjdk.i686 1:1.8.0.402.b06-1.el7_9 updates
java-1.8.0-openjdk.x86_64 1:1.8.0.402.b06-1.el7_9 updates
java-1.8.0-openjdk-accessibility.i686 1:1.8.0.402.b06-1.el7_9 updates
java-1.8.0-openjdk-accessibility.x86_64 1:1.8.0.402.b06-1.el7_9 updates
java-1.8.0-openjdk-demo.i686 1:1.8.0.402.b06-1.el7_9 updates
java-1.8.0-openjdk-demo.x86_64 1:1.8.0.402.b06-1.el7_9 updates
java-1.8.0-openjdk-devel.i686 1:1.8.0.402.b06-1.el7_9 updates
java-1.8.0-openjdk-devel.x86_64 1:1.8.0.402.b06-1.el7_9 updates
java-1.8.0-openjdk-headless.i686 1:1.8.0.402.b06-1.el7_9 updates
java-1.8.0-openjdk-headless.x86_64 1:1.8.0.402.b06-1.el7_9 updates
java-1.8.0-openjdk-javadoc.noarch 1:1.8.0.402.b06-1.el7_9 updates
java-1.8.0-openjdk-javadoc-zip.noarch 1:1.8.0.402.b06-1.el7_9 updates
java-1.8.0-openjdk-src.i686 1:1.8.0.402.b06-1.el7_9 updates
java-1.8.0-openjdk-src.x86_64 1:1.8.0.402.b06-1.el7_9 updates
5.使用 yum 安装 Java
[root@iZ7xv0ibz3fvihq4t7liz8Z opt]# yum install java-1.8.0.openjdk-devel.x86_64 -y
6.配置环境变量
JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.362.b08-1.el7_9.x86_64/
JRE_HOME=$JAVA_HOME/jre
CLASS_PATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar:$JRE_HOME/lib
PATH=$PATH:$JAVA_HOME/bin:$JRE_HOME/bin
export JAVA_HOME JRE_HOME CLASS_PATH PATH
