1. 下載jdk-8u112-linux-x64.tar.gz，最好用迅雷下載，速度快
http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html
2. 創(chuàng)建目錄
$ mkdir /usr/lib/jvm
$ tar -zxvf jdk-8u112-linux-x64.tar.gz -C /usr/lib/jvm
3. 修改環(huán)境變量：
$ vim ~/.bashrc 文件的末尾追加下面內(nèi)容:
#set oracle jdk environment
export JAVA_HOME=/usr/lib/jvm/jdk1.8.0_112
export JRE_HOME=${JAVA_HOME}/jre
export CLASSPATH=.:${JAVA_HOME}/lib:${JRE_HOME}/lib
export PATH=${JAVA_HOME}/bin:$PATH
4. 使環(huán)境變量馬上生效
$ source ~/.bashrc
5. 設(shè)置系統(tǒng)默認jdk 版本
$ update-alternatives --install /usr/bin/java java /usr/lib/jvm/jdk1.8.0_112/bin/java 300
$ update-alternatives --install /usr/bin/javac javac /usr/lib/jvm/jdk1.8.0_112/bin/javac 300
$ update-alternatives --install /usr/bin/jar jar /usr/lib/jvm/jdk1.8.0_112/bin/jar 300
$ update-alternatives --install /usr/bin/javah javah /usr/lib/jvm/jdk1.8.0_112/bin/javah 300
$ update-alternatives --install /usr/bin/javap javap /usr/lib/jvm/jdk1.8.0_112/bin/javap 300
$ update-alternatives --config java
6. 初次安裝jdk,會有下面的提示
There is only one alternative in link group java (providing /usr/bin/java):
/usr/lib/jvm/jdk1.7.0_60/bin/java
7. 測試jdk
$ java -version
