1. 下载

打开官网，选择对应版本下载
http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html
我这里选择复制下载链接，到Linux执行wget命令下载

wget http://download.oracle.com/otn-pub/java/jdk/8u171-b11/512cd62ec5174c3487ac17c61aaa89e8/jdk-8u171-linux-x64.tar.gz?AuthParam=1530583574_d8faee97d8100908926d4e654b5917b8

下载完成如下

--2018-07-03 10:04:44--  http://download.oracle.com/otn-pub/java/jdk/8u171-b11/512cd62ec5174c3487ac17c61aaa89e8/jdk-8u171-linux-x64.tar.gz?AuthParam=1530583574_d8faee97d8100908926d4e654b5917b8
Resolving download.oracle.com (download.oracle.com)... 23.35.194.209
Connecting to download.oracle.com (download.oracle.com)|23.35.194.209|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 190890122 (182M) [application/x-gzip]
Saving to: ‘jdk-8u171-linux-x64.tar.gz?AuthParam=1530583574_d8faee97d8100908926d4e654b5917b8’

jdk-8u171-linux-x64.tar.gz?AuthParam=1530 100%[=====================================================================================>] 182.05M  1.95MB/s    in 1m 42s

2018-07-03 10:06:26 (1.78 MB/s) - ‘jdk-8u171-linux-x64.tar.gz?AuthParam=1530583574_d8faee97d8100908926d4e654b5917b8’ saved [190890122/190890122]

2. 安装

• 在usr目录下新建java目录，将压缩包复制过去并解压，操作如下

cd /usr
mkdir java
cp jdk-8u171-linux-x64.tar.gz /usr/java/
tar -zxvf jdk-8u171-linux-x64.tar.gz

解压完成后，Java目录中的内容如下

total 183M
-rw-r--r-- 1 root root 183M Jul  3 10:14 jdk-8u171-linux-x64.tar.gz
drwxr-xr-x 0 uucp  143  512 Mar 29 08:18 jdk1.8.0_171

安装完成后可以建立个链接，节省目录长度，当然也可以不用

ln -s /usr/java/jdk1.8.0_171/ /usr/java8

3. 配置环境变量

修改profile内容

vim /etc/profile

在profile文件最下方加入如下内容

JAVA_HOME=/usr/java8
CLASSPATH=$JAVA_HOME/lib
PATH=$PATH:$JAVA_HOME/bin
export PATH JAVA_HOME CLASSPATH

保存退出执行source命令

source /etc/profile

4. 测试安装结果

执行java -version命令，返回如下结果即为安装成功

java version "1.8.0_171"
Java(TM) SE Runtime Environment (build 1.8.0_171-b11)
Java HotSpot(TM) 64-Bit Server VM (build 25.171-b11, mixed mode)