centOs安装jdk1.7

1，下载jdk-7u75-linux-x64.tar.gz，地址http://www.oracle.com/technetwork/java/javase/downloads/jdk7-downloads-1880260.html

2，确定系统是否自带jdk，如果自带，最好先卸载，卸载方法参见另一篇博文 卸载Centos自带open-jdk 

3，切换到root用户，新建 /usr/local/java 目录，并将安装包上传到该目录

#su root

#mkdir /usr/local/java 

4，解压 jdk-7u79-linux-x64.tar.gz

# tar xvf jdk-7u79-linux-x64.tar.gz 

5,设置环境变量，编辑/etc/profile文件，在最下面 追加 jdk安装路径

 #vi /etc/profile

export JAVA_HOME=/usr/local/java/jdk1.7.0_79
export JRE_HOME=/usr/local/java/jdk1.7.0_79/jre
export PATH=$PATH:/usr/local/java/jdk1.7.0_79/bin
export CLASSPATH=./:/usr/local/java/jdk1.7.0_79/lib:/usr/local/java/jdk1.7.0_79/jre/lib

6，设置环境变量生效，

#source profile

7，校验是否安装成功

#java -version