自己的阿里云ecs上装的系统是centos7.4,一般默认安装了open jdk.但是事实上很多应用软件可能对oracle jdk的支持更好,因此将open jdk换成oracle jdk8.
检查已存在java版本
查看java版本
使用命令$ java -version查看版本信息:
-bash: java: command not found
说明系统中没有安装java.
查看jdk版本
使用命令$ rpm -qa | grep java和$ rpm -qa | grep java查看jdk信息,没有输出任何内容,说明系统中没有任何的jdk的yum源.
总结
之前在自己的电脑中的虚拟机中安装的centos7是带open jdk的,这次阿里云上却没有.个人分析是因为自己在虚拟机中安装的时候勾选了比较多的选项,导致open jdk也被安装.而阿里云是面向无数用户,因此提供的centos是最纯净的版本,方便用户按需安装.
安装oracle jdk1.8
下载jdk1.8
使用wget命令下载:
$ wget --header "Cookie: oraclelicense=accept-securebackup-cookie" https://download.oracle.com/otn-pub/java/jdk/8u191-b12/2787e4a523244c269598db4e85c51e0c/jdk-8u191-linux-x64.rpm
注意: wget后面的header必须带上,否则一定会下载失败,我自己第一次就是因为没加header部分导致失败了.http部分对应的url根据版本会有变化,可以去Oracle官网Java SE Development Kit 8 Downloads获取.
输出
--2018-12-27 13:46:15-- https://download.oracle.com/otn-pub/java/jdk/8u191-b12/2787e4a523244c269598db4e85c51e0c/jdk-8u191-linux-x64.rpm
Resolving download.oracle.com (download.oracle.com)... 69.192.9.199
Connecting to download.oracle.com (download.oracle.com)|69.192.9.199|:443... connected.
HTTP request sent, awaiting response... 302 Moved Temporarily
Location: https://edelivery.oracle.com/otn-pub/java/jdk/8u191-b12/2787e4a523244c269598db4e85c51e0c/jdk-8u191-linux-x64.rpm [following]
--2018-12-27 13:46:15-- https://edelivery.oracle.com/otn-pub/java/jdk/8u191-b12/2787e4a523244c269598db4e85c51e0c/jdk-8u191-linux-x64.rpm
Resolving edelivery.oracle.com (edelivery.oracle.com)... 184.26.250.202, 2600:1417:76:19a::2d3e, 2600:1417:76:181::2d3e
Connecting to edelivery.oracle.com (edelivery.oracle.com)|184.26.250.202|:443... connected.
HTTP request sent, awaiting response... 302 Moved Temporarily
Location: http://download.oracle.com/otn-pub/java/jdk/8u191-b12/2787e4a523244c269598db4e85c51e0c/jdk-8u191-linux-x64.rpm?AuthParam=1545889696_3518430c799be5fff3fcd3909a875c61 [following]
--2018-12-27 13:46:16-- http://download.oracle.com/otn-pub/java/jdk/8u191-b12/2787e4a523244c269598db4e85c51e0c/jdk-8u191-linux-x64.rpm?AuthParam=1545889696_3518430c799be5fff3fcd3909a875c61
Connecting to download.oracle.com (download.oracle.com)|69.192.9.199|:80... connected.
HTTP request sent, awaiting response... 301 Moved Permanently
Location: https://download.oracle.com/otn-pub/java/jdk/8u191-b12/2787e4a523244c269598db4e85c51e0c/jdk-8u191-linux-x64.rpm?AuthParam=1545889696_3518430c799be5fff3fcd3909a875c61 [following]
--2018-12-27 13:46:16-- https://download.oracle.com/otn-pub/java/jdk/8u191-b12/2787e4a523244c269598db4e85c51e0c/jdk-8u191-linux-x64.rpm?AuthParam=1545889696_3518430c799be5fff3fcd3909a875c61
Connecting to download.oracle.com (download.oracle.com)|69.192.9.199|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 176154027 (168M) [application/x-redhat-package-manager]
Saving to: ‘jdk-8u191-linux-x64.rpm’
100%[==============================================================================================================>] 176,154,027 9.21MB/s in 18s
2018-12-27 13:46:35 (9.24 MB/s) - ‘jdk-8u191-linux-x64.rpm’ saved [176154027/176154027]
安装
执行
$ rpm -ivh jdk-8u191-linux-x64.rpm
输出
warning: jdk-8u191-linux-x64.rpm: Header V3 RSA/SHA256 Signature, key ID ec551f03: NOKEY
Preparing... ################################# [100%]
Updating / installing...
1:jdk1.8-2000:1.8.0_191-fcs ################################# [100%]
Unpacking JAR files...
tools.jar...
plugin.jar...
javaws.jar...
deploy.jar...
rt.jar...
jsse.jar...
charsets.jar...
localedata.jar...
此时再执行命令$ java -version查看:
java version "1.8.0_191"
Java(TM) SE Runtime Environment (build 1.8.0_191-b12)
Java HotSpot(TM) 64-Bit Server VM (build 25.191-b12, mixed mode)
执行命令$ rpm -qa | grep jdk输出
jdk1.8-1.8.0_191-fcs.x86_64
可见已经安装成功.
JDK会被默认安装在/usr/java中,执行$ cd /usr/java去/usr/java文件夹中,执行$ ls输出
default jdk1.8.0_191-amd64 latest
配置环境变量
环境变量的配置在/etc/profile文件中,$ vi /etc/profile在文件末尾添加下面的内容:
export JAVA_HOME=/usr/java/jdk1.8.0_191-amd64
export PATH=$JAVA_HOME/bin:$PATH
卸载jdk1.8
既然可以安装,那么该怎么卸载呢?首先执行$ rpm -qa | grep jdk输出jdk1.8-1.8.0_162-fcs.x86_64,说明jdk1.8-1.8.0_162-fcs.x86_64就是需要卸载的对象.
执行rpm -ev jdk1.8-1.8.0_162-fcs.x86_64卸载:
Preparing packages...
jdk1.8-2000:1.8.0_162-fcs.x86_64
此时再执行$ java -version输出
-bash: /usr/bin/java: No such file or directory
执行$ rpm -qa | grep jdk不输出任何内容.并且$ cd /usr/java中执行$ ls中不再输出任何内容,说明已经彻底卸载.
网友评论