Ubuntu 安裝 Sun JDK

1. 下載
    Oracle網站下載JDK7

     http://www.oracle.com/technetwork/java/javase/downloads/jdk7-downloads-1880260.html

    根據機器的操做系統選擇適合的版本，這裏咱們選擇 jdk-7u75-linux-x64.tar.gz

2. 安裝 

sudo mkdir /usr/lib/jvm
sudo tar zxvf ./jdk-7u75-linux-x64.tar.gz -C /usr/lib/jvm
cd /usr/lib/jvm
sudo mv jdk-7u75-linux-x64/ java-7-sun

3. 配置環境變量

    vi /etc/environment

    添加:    

export JAVA_HOME=/usr/lib/jvm/java-7-sun  
export JRE_HOME=${JAVA_HOME}/jre  
export CLASSPATH=.:${JAVA_HOME}/lib:${JRE_HOME}/lib  
export PATH=${JAVA_HOME}/bin:$PATH

    使配置 文件生效：source /etc/environment

4. 配置默認JDK

sudo update-alternatives --install /usr/bin/java java /usr/lib/jvm/java-7-sun/bin/java 300  
sudo update-alternatives --install /usr/bin/javac javac /usr/lib/jvm/java-7-sun/bin/javac 300  
sudo update-alternatives --install /usr/bin/jar jar /usr/lib/jvm/java-7-sun/bin/jar 300   
sudo update-alternatives --install /usr/bin/javah javah /usr/lib/jvm/java-7-sun/bin/javah 300   
sudo update-alternatives --install /usr/bin/javap javap /usr/lib/jvm/java-7-sun/bin/javap 300

    執行 sudo update-alternatives --config java 

5. 測試

    java -version