CentOS 7.3 中安装 JDK 及环境变量配置

- 日理万妓 2022-06-09 08:13 215阅读 0赞

Linux版本：`CentOS_7.3_x64`  
jdk版本：`jdk-8u144-linux-x64`

系统操作用户：`root`

## 一、查看并卸载系统中的 jdk ##

**（1）查看系统中 jdk 相关软件：**

[root@RemoteEshaon ~]# rpm -qa | grep java

输出：

javapackages-tools-3.4.1-6.el7_0.noarch
    python-javapackages-3.4.1-6.el7_0.noarch
    java-1.7.0-openjdk-1.7.0.75-2.5.4.2.el7_0.x86_64
    tzdata-java-2015a-1.el7.noarch
    java-1.7.0-openjdk-headless-1.7.0.75-2.5.4.2.el7_0.x86_64

**（2）卸载 jdk（若存在）**

[root@RemoteEshaon ~]# rpm -e --nodeps javapackages-tools-3.4.1-6.el7_0.noarch
    [root@RemoteEshaon ~]# rpm -e --nodeps python-javapackages-3.4.1-6.el7_0.noarch
    [root@RemoteEshaon ~]# rpm -e --nodeps tzdata-java-2015a-1.el7.noarch
    [root@RemoteEshaon ~]# rpm -e --nodeps java-1.7.0-openjdk-headless-1.7.0.75-2.5.4.2.el7_0.x86_64

**（3）查看卸载情况：**

[root@RemoteEshaon ~]# rpm -qa | grep java
    [root@RemoteEshaon ~]#

## 二、安装 jdk ##

Linux系统中安装jdk常用方法有[三种][Link 1]，这里采用 **rpm 安装 jdk**。  
根据[Linux 目录结构][Linux]的特点，准备将jdk安装到 **/usr** 目录下。  
**（1）在目录`/usr`下新建`java`目录：**

[root@RemoteEshaon ~]# mkdir /usr/java
    [root@RemoteEshaon ~]# cd /usr/java

（2）到[官网下载][Link 2] jdk-8u144-linux-x64.rpm  
使用 wget 命令【[参考stackoverflow][stackoverflow]】

[root@RemoteEshaon ~]# cd /usr/java
    [root@RemoteEshaon java]# wget --no-cookies --no-check-certificate --header "Cookie: oraclelicense=accept-securebackup-cookie" http://download.oracle.com/otn-pub/java/jdk/8u144-b01/090f390dda5b47b9b721c7dfaa008135/jdk-8u144-linux-x64.rpm

**（3）安装 jdk，默认安装到当前路径 `/usr/java`**

[root@RemoteEshaon java]# sudo yum localinstall jdk-8u144-linux-x64.rpm
    
    //...
    //...
    //...
    Installed:
      jdk-8u144-linux-x64.rpm 2000:1.8.0_102-fcs
    
    Complete!
    [root@RemoteEshaon java]#

**（4）查看 jdk 安装目录**

[root@RemoteEshaon java]# cd /usr/java
    [root@RemoteEshaon java]# ls -lsah
    total 12K
    4.0K drwxr-xr-x   3 root root 4.0K Aug 31 15:32 .
    4.0K drwxr-xr-x. 14 root root 4.0K Jul 22 13:15 ..
       0 lrwxrwxrwx   1 root root   16 Aug 31 15:24 default -> /usr/java/latest
    4.0K drwxr-xr-x   9 root root 4.0K Aug 31 15:24 jdk1.8.0_144
       0 lrwxrwxrwx   1 root root   22 Aug 31 15:24 latest -> /usr/java/jdk1.8.0_144
    [root@RemoteEshaon java]#

**（5）在当前目录下 `/usr/java` 检验安装是否成功**

[root@RemoteEshaon java]# java -version
    java version "1.8.0_144"
    Java(TM) SE Runtime Environment (build 1.8.0_144-b01)
    Java HotSpot(TM) 64-Bit Server VM (build 25.144-b01, mixed mode)
    [root@RemoteEshaon java]#

至此，安装成功！  
**（5）删除 RPM 文件**

[root@RemoteEshaon java]# rm -rf jdk-8u144-linux-x64.rpm

## 三、在 root 用户下配置 JDK 环境变量 ##

编辑环境变量配置文件：用Vim打开配置文件**`/etc/profile`**，在文件末尾加入下面代码，保存并退出。  
**（1）切换目录，打开配置文件`/etc/profile`**

[root@RemoteEshaon java]# cd /etc/
    [root@RemoteEshaon etc]# vim profile

**（2）在文件末尾加入下面代码：**

82 # User specific environment and startup programs
     83     export JAVA_HOME=/usr/java/jdk1.8.0_144
     84     export JRE_HOME=/usr/java/jdk1.8.0_144/jre
     85     export CLASSPATH=.:$JAVA_HOME/lib:$JRE_HOME/lib:$CLASSPATH
     86     export PATH=$JAVA_HOME/bin:$JRE_HOME/bin:$PATH

**（3）使环境变量即时生效：**

[root@RemoteEshaon etc]# source /etc/profile

**（4）测试 jdk 环境是否配置成功**

[root@RemoteEshaon etc]# cd 
    [root@RemoteEshaon ~]# java -version
    java version "1.8.0_144"
    Java(TM) SE Runtime Environment (build 1.8.0_144-b01)
    Java HotSpot(TM) 64-Bit Server VM (build 25.144-b01, mixed mode)
    [root@RemoteEshaon ~]#

至此，环境变量配置成功！

**【参考】**  
\[1\] [CentOS 7安装JDK][CentOS 7_JDK]  
\[2\] [How to install Oracle JDK 8 on CentOS][]  
\[3\] [LInux安装jdk的三种方法][Link 1]  
\[4\] [CentOS 7 配置Java环境变量][CentOS 7 _Java]  
\[5\] [每天一个linux命令（23）：Linux 目录结构][Linux]

[Link 1]: http://vvxyz.blog.51cto.com/809437/1642258
[Linux]: http://www.cnblogs.com/peida/archive/2012/11/21/2780075.html
[Link 2]: http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html
[stackoverflow]: https://stackoverflow.com/questions/10268583/downloading-java-jdk-on-linux-via-wget-is-shown-license-page-instead
[CentOS 7_JDK]: http://www.cnblogs.com/always-online/p/4691507.html
[How to install Oracle JDK 8 on CentOS]: https://www.mkyong.com/java/how-to-install-oracle-jdk-8-on-centos/
[CentOS 7 _Java]: https://my.oschina.net/bysu/blog/756580