云服务02-阿里云Centos7服务器安装jdk8

很多东西部署前必须得先安装jdk(Jenkins的运行需要依赖jdk),那么本篇文章主要针对“阿里云安装jdk8”进行讲解,希望感兴趣的小伙伴可以坚持看下去同时欢迎提出宝贵的意见让我们一起进步！

第一步：检查服务器自带的jdk版本

（1）linux命令为：rpm -qa|grep gcj

java:[root@iZ2zebjpjfqq58nc6ul6hnZ ~]# rpm -qa|grep jdk
[root@iZ2zebjpjfqq58nc6ul6hnZ ~]# 
发现查找无内容，则可以直接进行安装工作

第二步：下载jdk8安装包

（1）官网安装包地址：http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html
（2）找到“jdk-8u251-linux-x64.rpm”,点击“下载”按钮,跳转出下载链接,复制链接
（3）利用wget下载安装包

[root@iZ2zebjpjfqq58nc6ul6hnZ package]# wget https://download.oracle.com/otn/java/jdk/8u251-b08/3d5a2bb8f8d4428bbe94aed7ec7ae784/jdk-8u251-linux-x64.rpm?AuthParam=1587804398_738f2d81fe9d3cedef3b86c23f8a38ca
--2020-04-25 16:45:55--  https://download.oracle.com/otn/java/jdk/8u251-b08/3d5a2bb8f8d4428bbe94aed7ec7ae784/jdk-8u251-linux-x64.rpm?AuthParam=1587804398_738f2d81fe9d3cedef3b86c23f8a38ca
Resolving download.oracle.com (download.oracle.com)... 23.40.192.108
Connecting to download.oracle.com (download.oracle.com)|23.40.192.108|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 179472367 (171M) [application/x-redhat-package-manager]
Saving to: ‘jdk-8u251-linux-x64.rpm?AuthParam=1587804398_738f2d81fe9d3cedef3b86c23f8a38ca’

100%[==============================================================================================>] 179,472,367  968KB/s   in 2m 3s  

2020-04-25 16:48:00 (1.39 MB/s) - ‘jdk-8u251-linux-x64.rpm?AuthParam=1587804398_738f2d81fe9d3cedef3b86c23f8a38ca’ saved [179472367/179472367]

第三步：利用rpm安装jdk8

（1）linux命令为：rpm -ivh jdk-8u251-linux-x64.rpm

[root@iZ2zebjpjfqq58nc6ul6hnZ package]# rpm -ivh  jdk-8u251-linux-x64.rpm
warning: jdk-8u251-linux-x64.rpm: Header V3 RSA/SHA256 Signature, key ID ec551f03: NOKEY
Preparing...                          ################################# [100%]
Updating / installing...
   1:jdk1.8-2000:1.8.0_251-fcs        ################################# [100%]
Unpacking JAR files...
    tools.jar...
    plugin.jar...
    javaws.jar...
    deploy.jar...
    rt.jar...
    jsse.jar...
    charsets.jar...
    localedata.jar...

第四步：配置环境变量

（1）linux命令为：vim /etc/profile,进入文件profile文件进行配置环境变量

编辑的内容为：
# set jdk 
export JAVA_HOME=/usr/java/jdk1.8.0_251
export JRE_HOME=${JAVA_HOME}/jre
export CLASSPATH=.:${JAVA_HOME}/lib:${JRE_HOME}/lib
export PATH=${JAVA_HOME}/bin:$PATH

第五步：重启加载profile让系统文件生效

（1）linux命令为：source /etc/profile

第六步：验证是否安装成功

（1）linux命令为：java -version

[root@iZ2zebjpjfqq58nc6ul6hnZ package]# java -version
java version "1.8.0_251"
Java(TM) SE Runtime Environment (build 1.8.0_251-b08)
Java HotSpot(TM) 64-Bit Server VM (build 25.251-b08, mixed mode)