root@VM-0-16-ubuntu:~/software# ls
doctor
root@VM-0-16-ubuntu:~/software# wget https://download.java.net/java/GA/jdk21/fd2272bbf8e04c3dbaee13770090416c/35/GPL/openjdk-21_linux-x64_bin.tar.gz
--2025-10-26 20:18:46--  https://download.java.net/java/GA/jdk21/fd2272bbf8e04c3dbaee13770090416c/35/GPL/openjdk-21_linux-x64_bin.tar.gz
Resolving download.java.net (download.java.net)... 23.200.152.113
Connecting to download.java.net (download.java.net)|23.200.152.113|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 203348211 (194M) [application/x-gzip]
Saving to: ‘openjdk-21_linux-x64_bin.tar.gz’

openjdk-21_linux-x64_bin.tar.gz    100%[===============================================================>] 193.93M  12.4MB/s    in 17s     

2025-10-26 20:19:04 (11.7 MB/s) - ‘openjdk-21_linux-x64_bin.tar.gz’ saved [203348211/203348211]

root@VM-0-16-ubuntu:~/software# ll
total 198596
drwxr-xr-x 2 root root      4096 Oct 26 20:18 ./
drwx------ 8 root root      4096 Oct 26 20:02 ../
-rw-r--r-- 1 root root      1075 Oct 26 20:02 doctor
-rw-r--r-- 1 root root 203348211 Aug 12  2023 openjdk-21_linux-x64_bin.tar.gz
### 解压缩
root@VM-0-16-ubuntu:~/software# tar -zxvf openjdk-21_linux-x64_bin.tar.gz 
jdk-21/bin/jar
jdk-21/bin/jarsigner
jdk-21/bin/java
... ...
jdk-21/lib/tzdb.dat
jdk-21/release
root@VM-0-16-ubuntu:~/software# ll
... ...
-rw-r--r-- 1 root root      1075 Oct 26 20:02 doctor
drwxr-xr-x 8 root root      4096 Oct 26 20:19 jdk-21/
-rw-r--r-- 1 root root 203348211 Aug 12  2023 openjdk-21_linux-x64_bin.tar.gz
### 将jdk-21移动到/usr/java/目录
root@VM-0-16-ubuntu:~/software# mv jdk-21/ /usr/java/
### 进入/usr/java/
root@VM-0-16-ubuntu:~/software# cd /usr/java/
root@VM-0-16-ubuntu:/usr/java# ls
jdk-21
### 打印当前目录
root@VM-0-16-ubuntu:/usr/java# pwd
/usr/java
root@VM-0-16-ubuntu:/usr/java# cd jdk-21/
root@VM-0-16-ubuntu:/usr/java/jdk-21# ll
total 36
drwxr-xr-x  8 root  root  4096 Oct 26 20:19 ./
drwxr-xr-x  3 root  root  4096 Oct 26 20:21 ../
drwxr-xr-x  2 root  root  4096 Oct 26 20:19 bin/
drwxr-xr-x  5 root  root  4096 Oct 26 20:19 conf/
drwxr-xr-x  3 root  root  4096 Oct 26 20:19 include/
drwxr-xr-x  2 root  root  4096 Oct 26 20:19 jmods/
drwxr-xr-x 71 root  root  4096 Oct 26 20:19 legal/
drwxr-xr-x  5 root  root  4096 Oct 26 20:19 lib/
-rw-r--r--  1 10668 10668 1217 Aug 10  2023 release
### 打开/etc/profile 配置环境变量
root@VM-0-16-ubuntu:/usr/java/jdk-21# vim /etc/profile
### 使配置的环境变量生效
root@VM-0-16-ubuntu:/usr/java/jdk-21# source /etc/profile
### 查看jdk的版本,检查jdk是否安装成功
root@VM-0-16-ubuntu:/usr/java/jdk-21# java -version
openjdk version "21" 2023-09-19
OpenJDK Runtime Environment (build 21+35-2513)
OpenJDK 64-Bit Server VM (build 21+35-2513, mixed mode, sharing)