CentOS7安装JDK完整步骤

1.下载地址

https://www.oracle.com/java/technologies/downloads/#java8

2.确认服务器中安装的java版本

[root@icoolkj soft]# java -version
-bash: java: command not found
[root@icoolkj soft]# 

3.查询并卸载

[root@icoolkj soft]# rpm -qa | grep java 
[root@icoolkj soft]# 

#卸载
rpm -e --nodeps xxxxxxxxx

4.准备好所需版本的jdk的rpm包，并上传至服务器

[root@icoolkj soft]# ll
total 130160
-rw-r--r--.  1 root root  117557932 Nov 19 17:36 jdk-8u351-linux-x64.rpm

5.解压安装，默认情况下安装在/usr/java

[root@icoolkj soft]# rpm -ivh jdk-8u351-linux-x64.rpm 
warning: jdk-8u351-linux-x64.rpm: Header V3 RSA/SHA256 Signature, key ID ec551f03: NOKEY
Preparing...                          ################################# [100%]
Updating / installing...
   1:jdk1.8-2000:1.8.0_351-fcs        ################################# [100%]
Unpacking JAR files...
	tools.jar...
	plugin.jar...
	javaws.jar...
	deploy.jar...
	rt.jar...
	jsse.jar...
	charsets.jar...
	localedata.jar...
[root@icoolkj soft]# cd /usr/java
[root@icoolkj java]# pwd
/usr/java
[root@icoolkj java]# ll
total 0
lrwxrwxrwx. 1 root root  16 Nov 19 17:42 default -> /usr/java/latest
drwxr-xr-x. 9 root root 286 Nov 19 17:42 jdk1.8.0_351-amd64
lrwxrwxrwx. 1 root root  28 Nov 19 17:42 latest -> /usr/java/jdk1.8.0_351-amd64
[root@icoolkj java]# 

6.查看安装成功与否

[root@icoolkj soft]# java -version
java version "1.8.0_351"
Java(TM) SE Runtime Environment (build 1.8.0_351-b10)
Java HotSpot(TM) 64-Bit Server VM (build 25.351-b10, mixed mode)
[root@icoolkj soft]# 

7.修改系统环境变量，设置JAVA_HOME

[root@icoolkj java]# vi /etc/profile
[root@icoolkj java]# 

修改/etc/profile文件下添加如下代码

JAVA_HOME=/usr/java/jdk1.8.0_351-amd64
JRE_HOME=/usr/java/jdk1.8.0_351-amd64/jre
PATH=$PATH:$JAVA_HOME/bin:$JRE_HOME/bin
CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar:$JRE_HOME/lib
export JAVA_HOME JRE_HOME PATH CLASSPATH

8.使环境变量生效

[root@icoolkj java]# source /etc/profile
[root@icoolkj java]#