双十一搞了个腾讯云，配置一下jdk环境。检查是否已安装JDK 及卸载 从下面命令行可以看出，本系统没有安装过java环境。[root@VM-0-10-centos /]# yum list installed | grep java [root@VM-0-10-centos /]# 如果需要卸载请用下面的命令：yum -y remove 当然你也可以切换不同版本的jdk也就没有必要卸载了。 查看JDK 软件包列表yum search java | grep -i --color jdk[root@VM-0-10-centos /]# yum search java | grep -i --color jdk ldapjdk-javadoc.noarch : Javadoc for ldapjdk icedtea-web.x86_64 : Additional Java components for OpenJDK - Java browser java-1.6.0-openjdk.x86_64 : OpenJDK Runtime Environment java-1.6.0-openjdk-demo.x86_64 : OpenJDK Demos java-1.6.0-openjdk-devel.x86_64 : OpenJDK Development Environment java-1.6.0-openjdk-javadoc.x86_64 : OpenJDK API Documentation java-1.6.0-openjdk-src.x86_64 : OpenJDK Source Bundle java-1.7.0-openjdk.x86_64 : OpenJDK Runtime Environment java-1.7.0-openjdk-accessibility.x86_64 : OpenJDK accessibility connector java-1.7.0-openjdk-demo.x86_64 : OpenJDK Demos java-1.7.0-openjdk-devel.x86_64 : OpenJDK Development Environment java-1.7.0-openjdk-headless.x86_64 : The OpenJDK runtime environment without java-1.7.0-openjdk-javadoc.noarch : OpenJDK API Documentation java-1.7.0-openjdk-src.x86_64 : OpenJDK Source Bundle java-1.8.0-openjdk.i686 : OpenJDK Runtime Environment 8 java-1.8.0-openjdk.x86_64 : OpenJDK Runtime Environment 8 java-1.8.0-openjdk-accessibility.i686 : OpenJDK accessibility connector java-1.8.0-openjdk-accessibility.x86_64 : OpenJDK accessibility connector java-1.8.0-openjdk-demo.i686 : OpenJDK Demos 8 java-1.8.0-openjdk-demo.x86_64 : OpenJDK Demos 8 java-1.8.0-openjdk-devel.i686 : OpenJDK Development Environment 8 java-1.8.0-openjdk-devel.x86_64 : OpenJDK Development Environment 8 java-1.8.0-openjdk-headless.i686 : OpenJDK Headless Runtime Environment 8 java-1.8.0-openjdk-headless.x86_64 : OpenJDK Headless Runtime Environment 8 java-1.8.0-openjdk-javadoc.noarch : OpenJDK 8 API documentation java-1.8.0-openjdk-javadoc-zip.noarch : OpenJDK 8 API documentation compressed java-1.8.0-openjdk-src.i686 : OpenJDK Source Bundle 8 java-1.8.0-openjdk-src.x86_64 : OpenJDK Source Bundle 8 java-11-openjdk.i686 : OpenJDK Runtime Environment 11 java-11-openjdk.x86_64 : OpenJDK Runtime Environment 11 java-11-openjdk-demo.i686 : OpenJDK Demos 11 java-11-openjdk-demo.x86_64 : OpenJDK Demos 11 java-11-openjdk-devel.i686 : OpenJDK Development Environment 11 java-11-openjdk-devel.x86_64 : OpenJDK Development Environment 11 java-11-openjdk-headless.i686 : OpenJDK Headless Runtime Environment 11 java-11-openjdk-headless.x86_64 : OpenJDK Headless Runtime Environment 11 java-11-openjdk-javadoc.i686 : OpenJDK 11 API documentation java-11-openjdk-javadoc.x86_64 : OpenJDK 11 API documentation java-11-openjdk-javadoc-zip.i686 : OpenJDK 11 API documentation compressed in a java-11-openjdk-javadoc-zip.x86_64 : OpenJDK 11 API documentation compressed in java-11-openjdk-jmods.i686 : JMods for OpenJDK 11 java-11-openjdk-jmods.x86_64 : JMods for OpenJDK 11 java-11-openjdk-src.i686 : OpenJDK Source Bundle 11 java-11-openjdk-src.x86_64 : OpenJDK Source Bundle 11 java-latest-openjdk.x86_64 : OpenJDK Runtime Environment 14 java-latest-openjdk-debug.x86_64 : OpenJDK Runtime Environment 14 with full 选择版本安装 OpenJDK Runtime Environment:Java程序的运行环境，包含了java虚拟机，java基础类库； OpenJDK Development Environment：Java程序的开发环境，编写java程序所需的开发工具包JDK包含了JRE，同时还包含了编译java源码的编译器javac，还包含了很多java程序调试和分析的工具：jconsole，jvisualvm等工具软件； 我们装一个1.8的运行环境就可以了，毕竟服务器才40G能省则省#OpenJDK Runtime Environment yum install -y java-1.8.0-openjdk.x86_64 #OpenJDK Development Environment yum install -y java-1.8.0-openjdk-devel.x86_64[root@VM-0-10-centos /]# java -version openjdk version ＂1.8.0_272＂ OpenJDK Runtime Environment (build 1.8.0_272-b10) OpenJDK 64-Bit Server VM (build 25.272-b10, mixed mode) 默认安装路径在：/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.272.b10-1.el7_9.x86_64/jre。通过yum安装的jdk就不需要配置环境变量了