centos安装JDK8
概述
记录CentOS安装JDK8的过程。
软件环境
CentOS：6.5，x86-64位版本
JDK： 8.0，x86-64位版本,rpm格式
安装
首先切换到root：
```
su - root
```
然后安装jdk：
```
rpm -ivh jdk-8-linux-x64.rpm
Preparing... ########################################### [100%]
1:jdk ########################################### [100%]
Unpacking JAR files...
rt.jar...
Error: Could not open input file: /usr/java/jdk1.8.0/jre/lib/rt.pack
Error: unpack could not create JAR file:
/usr/java/jdk1.8.0/jre/lib/rt.jar
Please refer to the Troubleshooting section of the Installation Instructions
on the download page.
jsse.jar...
Error: Could not open input file: /usr/java/jdk1.8.0/jre/lib/jsse.pack
Error: unpack could not create JAR file:
/usr/java/jdk1.8.0/jre/lib/jsse.jar
Please refer to the Troubleshooting section of the Installation Instructions
on the download page.
charsets.jar...
Error: Could not open input file: /usr/java/jdk1.8.0/jre/lib/charsets.pack
Error: unpack could not create JAR file:
/usr/java/jdk1.8.0/jre/lib/charsets.jar
Please refer to the Troubleshooting section of the Installation Instructions
on the download page.
tools.jar...
Error: Could not open input file: /usr/java/jdk1.8.0/lib/tools.pack
Error: unpack could not create JAR file:
/usr/java/jdk1.8.0/lib/tools.jar
Please refer to the Troubleshooting section of the Installation Instructions
on the download page.
localedata.jar...
Error: Could not open input file: /usr/java/jdk1.8.0/jre/lib/ext/localedata.pack
Error: unpack could not create JAR file:
/usr/java/jdk1.8.0/jre/lib/ext/localedata.jar
Please refer to the Troubleshooting section of the Installation Instructions
on the download page.
jfxrt.jar...
Error: Could not open input file: /usr/java/jdk1.8.0/jre/lib/ext/jfxrt.pack
Error: unpack could not create JAR file:
/usr/java/jdk1.8.0/jre/lib/ext/jfxrt.jar
Please refer to the Troubleshooting section of the Installation Instructions
on the download page.
```
出现上面的错误是因为系统中已经有JDK的其他版本，使用`rpm -qa | grep jdk`查询存在的jdk，并用`rpm -e`命令移除。之后再次执行安装，顺利通过
```
Preparing... ########################################### [100%]
1:jdk ########################################### [100%]
Unpacking JAR files...
rt.jar...
jsse.jar...
charsets.jar...
tools.jar...
localedata.jar...
jfxrt.jar...
```
配置环境变量
编辑环境变量，配置path和classpath。vi /etc/profile，增加下面配置：
```
export JAVA_HOME=/usr/java/jdk1.8.0/
export CLASSPATH=.:$JAVA_HOME/jre/lib/rt.jar:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
export PATH=$PATH:$JAVA_HOME/bin
```
保存退出后，执行`source /etc/profile`使变更生效。
检测安装的是否正确，在shell中执行`java -version`和`javac -version`，如果shell显示如下的信息，表示安装成功：
```
[root@localhost Downloads]# java -version
java version "1.8.0"
Java(TM) SE Runtime Environment (build 1.8.0-b132)
Java HotSpot(TM) 64-Bit Server VM (build 25.0-b70, mixed mode)
[root@localhost Downloads]# javac -version
javac 1.8.0
```