1. 打開官網下載Java安裝文件
 

jdk-7u15-linux-x64.tar.gz

2.打開終端，根據個人習慣建立目錄

sudo mkdir /usr/local/development

3.將下載的文件移動到這個文件夾下面并進行解壓。使用如下命令：

sudo mv jdk-7u15-linux-x64.tar.gz /usr/local/development
 

sudo tar -zxvf jdk-7u15-linux-x64.tar.gz

4.修改環境變量

sudo gedit /etc/environment
源文件的內容是這樣的：

PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games"
修改為：

PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:${JAVA_HOME}/bin"
JAVA_HOME=/usr/local/development/jdk1.7.0_15
JRE_HOME=${JAVA_HOME}/jre
 

CLASSPATH=.:${JAVA_HOME}/lib:${JRE_HOME}/lib"

5.重新加載bashrc

source ~/.bashrc

6.配置默認JDK

sudo update-alternatives --install /usr/bin/java java /usr/local/development/jdk1.7.0_15/bin/java 300

sudo update-alternatives --install /usr/bin/javac javac /usr/local/development/jdk1.7.0_15/bin/javac 300
sudo update-alternatives --install /usr/bin/javap javap /usr/local/development/jdk1.7.0_15/bin/javap 300
 

sudo update-alternatives --install /usr/bin/javadoc javadoc /usr/local/development/jdk1.7.0_15/bin/javadoc 300

7.測試：

java -version
如下顯示表示配置成功：
arlen@Arlen-TOP2:~$ java -version
java version "1.7.0_15"
Java(TM) SE Runtime Environment (build 1.7.0_15-b03)
Java HotSpot(TM) 64-Bit Server VM (build 23.7-b01, mixed mode)
arlen@Arlen-TOP2:~$