Linux下安装jdk

首先先检查linux机器上是否有自带的jdk

java -version检查下就可以，如果有版本低的话可以先卸载掉方法如下

[root@localhost java]# rpm -qa|grep gcj 或者 rpm -qa|grep java

libgcj-4.1.2-44.el5

java-1.4.2-gcj-compat-1.4.2.0-40jpp.115

如果没有信息就是没有安装、如果有那么如下操作

[root@localhost jdk-6u13-linux-i586]# yum -y remove java-1.4.2-gcj-compat-1.4.2.0-40jpp.115   或者 rpm -e --nodeps java-1.4.2-gcj-compat-1.4.2.0-40jpp.115

Loaded plugins: rhnplugin, security

This system is not registered with RHN.

RHN support will be disabled.

Setting up Remove Process

Resolving Dependencies

--> Running transaction check

---> Package java-1.4.2-gcj-compat.i386 0:1.4.2.0-40jpp.115 set to be erased

--> Processing Dependency: java-gcj-compat for package: antlr

--> Processing Dependency: java-gcj-compat for package: antlr

--> Processing Dependency: java-gcj-compat >= 1.0.64 for package: gjdoc

--> Processing Dependency: java-gcj-compat >= 1.0.64 for package: gjdoc

--> Running transaction check

---> Package antlr.i386 0:2.7.6-4jpp.2 set to be erased

---> Package gjdoc.i386 0:0.7.7-12.el5 set to be erased

--> Finished Dependency Resolution

Dependencies Resolved

================================================================================

 Package                   Arch     Version                 Repository     Size

================================================================================

Removing:

 java-1.4.2-gcj-compat     i386     1.4.2.0-40jpp.115       installed      441 

Removing for dependencies:

 antlr                     i386     2.7.6-4jpp.2            installed     2.5 M

 gjdoc                     i386     0.7.7-12.el5            installed     1.7 M

Transaction Summary

================================================================================

Install      0 Package(s)         

Update       0 Package(s)         

Remove       3 Package(s)         

Downloading Packages:

Running rpm_check_debug

Running Transaction Test

Finished Transaction Test

Transaction Test Succeeded

Running Transaction

  Erasing        : antlr                                             [1/3] 

  Erasing        : gjdoc                                             [2/3] 

  Erasing        : java-1.4.2-gcj-compat                             [3/3] 

Removed: java-1.4.2-gcj-compat.i386 0:1.4.2.0-40jpp.115

Dependency Removed: antlr.i386 0:2.7.6-4jpp.2 gjdoc.i386 0:0.7.7-12.el5

Complete!(看到这个说明完成了。。)

接着我们手动安装linux的jdk我的

下载地址
http://www.oracle.com/technetwork/java/javase/downloads/java-se-jdk-7-download-432154.html
我下载的是rpm包

接着执行安装

[root@localhost local]# rpm -ivh jdk-7u79-linux-x64.rpm

Preparing...                ########################################### [100%]

   1:jdk                    ########################################### [100%]

Unpacking JAR files...

        rt.jar...

        jsse.jar...

        charsets.jar...

        tools.jar...

        localedata.jar...

        jfxrt.jar...

我的rpm包就这样就装好了。。

接着是配置环境变量

#vi  /etc/profile

在该profile文件中最下面添加：

JAVA_HOME=/usr/java/jdk1.7.0_79/

JRE_HOME=/usr/java/jdk1.7.0_79/jre

PATH=$PATH:$JAVA_HOME/bin:$JRE_HOME/bin

CLASSPATH=.:$JAVA_HOME/lib/jt.jar:$JAVA_HOME/lib/tools.jar:$JRE_HOME/lib

export JAVA_HOME JRE_HOME PATH CLASSPATH

添加完毕保存退出

添加完毕保存退出

source /etc/profile

[root@localhost jdk1.7.0]# java -version

java version "1.7.0"

Java(TM) SE Runtime Environment (build 1.7.0-b147)

Java HotSpot(TM) Client VM (build 21.0-b17, mixed mode, sharing)

[root@localhost jdk1.7.0]# echo $JAVA_HOME

/usr/java/jdk1.7.0

这个时候就大功告成了