ubuntu 10.04安装JDK7

1. 从oracle官方网站下载JDK7，地址如下：(根据系统的版本自行选择)

http://download.oracle.com/otn-pub/java/jdk/7u9-b05/jdk-7u9-linux-i586.tar.gz 

2. 把下载后的文件解压缩

sudo tar -zxf jdk-7u9-linux-i586.tar.gz 

3. 移动JDK文件到/usr/lib/jvm目录下

sudo mv jdk1.7.0_09 /etc/lib/jvm/

4. 配置java jdk环境变量

sudo gedit /etc/environment

打开文件后，按如下内容做相应的更改

PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/lib/jvm/java-7-sun/bin"

CLASSPATH=.:/usr/lib/jvm/java-7-sun/lib

JAVA_HOME=/usr/lib/jvm/java-7-sun

5. 重新加载.bashrc文件

source ~/.bashrc

6. 执行下面的命令

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/javap javap /usr/lib/jvm/java-7-sun/bin/javap 300

sudo update-alternatives --install /usr/bin/javadoc javadoc /usr/lib/jvm/java-7-sun/bin/javadoc 300

7. 测试环境变量否配置成功

java -version

看到如下消息说明已经没问题了

java version "1.7.0_09"

Java(TM) SE Runtime Environment (build 1.7.0_09-b05)

Java HotSpot(TM) Client VM (build 23.5-b02, mixed mode)