CentOS 7安装Java

本文介绍在Vagrant搭建的CentOS安装OpenJDK。

1. 启动虚拟机

D:\sandbox\code\demo>vagrant up
Bringing machine 'default' up with 'virtualbox' provider...
==> default: Resuming suspended VM...
==> default: Booting VM...
==> default: Waiting for machine to boot. This may take a few minutes...
    default: SSH address: 127.0.0.1:2222
    default: SSH username: vagrant
    default: SSH auth method: private key
==> default: Machine booted and ready!
==> default: Machine already provisioned. Run `vagrant provision` or use the `--provision`
==> default: flag to force provisioning. Provisioners marked to run always will still run.

2. ssh登录虚拟机

D:\sandbox\code\demo>vagrant ssh
Last login: Tue Nov  9 14:15:16 2021 from 10.0.2.2
Last login: Tue Nov  9 14:15:16 2021 from 10.0.2.2
[vagrant@localhost ~]$

3. 安装OpenJDK 11

[vagrant@localhost ~]$ sudo yum install java-11-openjdk-devel

4. 确认Java安装成功

[vagrant@localhost ~]$ java -version
openjdk version "11.0.13" 2021-10-19 LTS
OpenJDK Runtime Environment 18.9 (build 11.0.13+8-LTS)
OpenJDK 64-Bit Server VM 18.9 (build 11.0.13+8-LTS, mixed mode, sharing)

5. 安装OpenJDK 8

[vagrant@localhost ~]$ sudo yum install java-1.8.0-openjdk-devel

6. 虽然安装了两个版本的JDK,但是默认JDK是11

[vagrant@localhost ~]$ java -version
openjdk version "11.0.13" 2021-10-19 LTS
OpenJDK Runtime Environment 18.9 (build 11.0.13+8-LTS)
OpenJDK 64-Bit Server VM 18.9 (build 11.0.13+8-LTS, mixed mode, sharing)

7. 如果要切换默认JDK的版本,可以

[vagrant@localhost ~]$ sudo alternatives --config java

There are 2 programs which provide 'java'.

  Selection    Command
-----------------------------------------------
 + 1           java-11-openjdk.x86_64 (/usr/lib/jvm/java-11-openjdk-11.0.13.0.8-1.el7_9.x86_64/bin/java)
*  2           java-1.8.0-openjdk.x86_64 (/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.312.b07-1.el7_9.x86_64/jre/bin/java)

Enter to keep the current selection[+], or type selection number:

8. 如果要卸载JDK

sudo yum remove java-1.8.0-openjdk-devel

参考

How to Install Java on CentOS 7

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