Ubuntu 12.04 x64 安装jdk-7u45-linux-x64.tar.gz过程记录

Ubuntu 12.04 x64 安装jdk-7u45-linux-x64.tar.gz过程记录：

1.首先下载最新版 jdk 64-bit版 (jdk-7u45-linux-x64.tar.gz)

从官网下载http://www.oracle.com/technetwork/java/javase/downloads/jdk7-downloads-1880260.html

2.将jdk-7u45-linux-x64.tar.gz拷贝到/opt/java:

sudo mkdir -p /opt/java

sudo cp ~/Downloads/jdk-7u45-linux-x64.tar.gz /opt/java

cd /opt/java

sudo tar -xzvf jdk-7u45-linux-x64.tar.gz    //解压缩文件

sudo rm jdk-7u45-linux-x64.tar.gz

3.设置环境变量，
sudo vi /etc/profile

在文件的最后面增长：

export JAVA_HOME=/opt/java/jdk1.7.0_45

export JRE_HOME=/opt/java/jdk1.7.0_45/jre

export PATH=$JAVA_HOME/bin:$JAVA_HOME/jre/bin:$PATH

export CLASSPATH=$CLASSPATH:.:$JAVA_HOME/lib:$JAVA_HOME/jre/lib

4.将系统默认的jdk修改过来(可选)

$ sudo update-alternatives --install /usr/bin/java java /usr/lib/jvm/jdk1.7.0_45/bin/java 300

$ sudo update-alternatives --install /usr/bin/javac javac /usr/lib/jvm/jdk1.7.0_45/bin/javac 300

$ sudo update-alternatives --config java

$ sudo update-alternatives --config javac

5.检测，输入java -version

java version "1.7.0_45"

Java(TM) SE Runtime Environment (build 1.7.0_45-b18)

Java HotSpot(TM) 64-Bit Server VM (build 24.45-b08, mixed mode)