如何(怎样)在CentOS 6.X 或 redhat 上使用安装JDK runtime environment (openjdk) ?
CentOS 6.X 和 5.X 自带有OpenJDK runtime environment (openjdk)。它是一个在linux上实现开源的java 平台。CentOS yum 命令 安装 Java SDK openjdk
centos linux JAVA(openjdk)软件包名
1.java-1.7.0-openjdk - OpenJDK Runtime Environment
2.java-1.7.0-openjdk-devel - OpenJDK Development Environment
输入以下命令，以查看可用的JDK软件包列表;
[root@dabu.info ~]# yum search java | grep -i --color JDK
输出类似下图：
centos-openjdk
在CentOS linux安装 JAVA SDK
在命令行终端以root用户 输入以下命令yum安装 OpenSDK ：
[root@dabu.info ~]#yum install java-1.7.0-openjdk java-1.7.0-openjdk-devel #安装openjdk
输出如下：
Loaded plugins: downloadonly,fastestmirror,security
Loading mirror speeds from cached hostfile
* base: mirror.wiredtree.com
* epel: mirror.steadfast.net
* extras: bay.uchicago.edu
* updates: mirror.team-cymru.org
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package java-1.7.0-openjdk.x86_64 1:1.7.0.51-2.4.4.1.el6_5 will be installed
--> Processing Dependency: jpackage-utils >= 1.7.3-1jpp.2 for package: 1:java-1.7.0-openjdk-1.7.0.51-2.4.4.1.el6_5.x86_64
--> Processing Dependency: xorg-x11-fonts-Type1 for package: 1:java-1.7.0-openjdk-1.7.0.51-2.4.4.1.el6_5.x86_64
--> Processing Dependency: tzdata-java for package: 1:java-1.7.0-openjdk-1.7.0.51-2.4.4.1.el6_5.x86_64
--> Processing Dependency: rhino for package: 1:java-1.7.0-openjdk-1.7.0.51-2.4.4.1.el6_5.x86_64
--> Processing Dependency: libpulse.so.0(PULSE_0)(64bit) for package: 1:java-1.7.0-openjdk-1.7.0.51-2.4.4.1.el6_5.x86_64
--> Processing Dependency: libasound.so.2(ALSA_0.9.0rc4)(64bit) for package: 1:java-1.7.0-openjdk-1.7.0.51-2.4.4.1.el6_5.x86_64
--> Processing Dependency: libasound.so.2(ALSA_0.9)(64bit) for package: 1:java-1.7.0-openjdk-1.7.0.51-2.4.4.1.el6_5.x86_64
--> Processing Dependency: libpulse.so.0()(64bit) for package: 1:java-1.7.0-openjdk-1.7.0.51-2.4.4.1.el6_5.x86_64
--> Processing Dependency: libgif.so.4()(64bit) for package: 1:java-1.7.0-openjdk-1.7.0.51-2.4.4.1.el6_5.x86_64
--> Processing Dependency: libasound.so.2()(64bit) for package: 1:java-1.7.0-openjdk-1.7.0.51-2.4.4.1.el6_5.x86_64
--> Processing Dependency: libXtst.so.6()(64bit) for package: 1:java-1.7.0-openjdk-1.7.0.51-2.4.4.1.el6_5.x86_64
---> Package alsa-lib.x86_64 0:1.0.22-3.el6 will be installed
---> Package giflib.x86_64 0:4.1.6-3.1.el6 will be installed
--> Processing Dependency: libSM.so.6()(64bit) for package: giflib-4.1.6-3.1.el6.x86_64
--> Processing Dependency: libICE.so.6()(64bit) for package: giflib-4.1.6-3.1.el6.x86_64
---> Package jpackage-utils.noarch 0:1.7.5-3.12.el6 will be installed
---> Package libXtst.x86_64 0:1.2.1-2.el6 will be installed
---> Package pulseaudio-libs.x86_64 0:0.9.21-14.el6_3 will be installed
--> Processing Dependency: libsndfile.so.1(libsndfile.so.1.0)(64bit) for package: pulseaudio-libs-0.9.21-14.el6_3.x86_64
--> Processing Dependency: libsndfile.so.1()(64bit) for package: pulseaudio-libs-0.9.21-14.el6_3.x86_64
--> Processing Dependency: libasyncns.so.0()(64bit) for package: pulseaudio-libs-0.9.21-14.el6_3.x86_64
---> Package rhino.noarch 0:1.7-0.7.r2.2.el6 will be installed
--> Processing Dependency: jline for package: rhino-1.7-0.7.r2.2.el6.noarch
---> Package tzdata-java.noarch 0:2013i-2.el6 will be installed
---> Package xorg-x11-fonts-Type1.noarch 0:7.2-9.1.el6 will be installed
--> Processing Dependency: ttmkfdir for package: xorg-x11-fonts-Type1-7.2-9.1.el6.noarch
--> Processing Dependency: mkfontdir for package: xorg-x11-fonts-Type1-7.2-9.1.el6.noarch
---> Package jline.noarch 0:0.9.94-0.8.el6 will be installed
---> Package libICE.x86_64 0:1.0.6-1.el6 will be installed
---> Package libSM.x86_64 0:1.2.1-2.el6 will be installed
---> Package libasyncns.x86_64 0:0.8-1.1.el6 will be installed
---> Package libsndfile.x86_64 0:1.0.20-5.el6 will be installed
--> Processing Dependency: libvorbisenc.so.2()(64bit) for package: libsndfile-1.0.20-5.el6.x86_64
--> Processing Dependency: libvorbis.so.0()(64bit) for package: libsndfile-1.0.20-5.el6.x86_64
--> Processing Dependency: libogg.so.0()(64bit) for package: libsndfile-1.0.20-5.el6.x86_64
--> Processing Dependency: libFLAC.so.8()(64bit) for package: libsndfile-1.0.20-5.el6.x86_64
---> Package ttmkfdir.x86_64 0:3.0.9-32.1.el6 will be installed
---> Package xorg-x11-font-utils.x86_64 1:7.2-11.el6 will be installed
--> Processing Dependency: libfontenc.so.1()(64bit) for package: 1:xorg-x11-font-utils-7.2-11.el6.x86_64
--> Processing Dependency: libXfont.so.1()(64bit) for package: 1:xorg-x11-font-utils-7.2-11.el6.x86_64
---> Package flac.x86_64 0:1.2.1-6.1.el6 will be installed
---> Package libXfont.x86_64 0:1.4.5-3.el6_5 will be installed
---> Package libfontenc.x86_64 0:1.0.5-2.el6 will be installed
---> Package libogg.x86_64 2:1.1.4-2.1.el6 will be installed
---> Package libvorbis.x86_64 1:1.2.3-4.el6_2.1 will be installed
--> Finished Dependency Resolution
Dependencies Resolved
==================================================================================================
Package Arch Version Repository Size
Installing:
java-1.7.0-openjdk x86_64 1:1.7.0.51-2.4.4.1.el6_5 updates 26 M
Installing for dependencies:
alsa-lib x86_64 1.0.22-3.el6 base 370 k
flac x86_64 1.2.1-6.1.el6 base 243 k
giflib x86_64 4.1.6-3.1.el6 base 37 k
jline noarch 0.9.94-0.8.el6 base 86 k
jpackage-utils noarch 1.7.5-3.12.el6 base 59 k
libICE x86_64 1.0.6-1.el6 base 53 k
libSM x86_64 1.2.1-2.el6 base 37 k
libXfont x86_64 1.4.5-3.el6_5 updates 136 k
libXtst x86_64 1.2.1-2.el6 base 29 k
libasyncns x86_64 0.8-1.1.el6 base 24 k
libfontenc x86_64 1.0.5-2.el6 base 24 k
libogg x86_64 2:1.1.4-2.1.el6 base 21 k
libsndfile x86_64 1.0.20-5.el6 base 233 k
libvorbis x86_64 1:1.2.3-4.el6_2.1 base 168 k
pulseaudio-libs x86_64 0.9.21-14.el6_3 base 462 k
rhino noarch 1.7-0.7.r2.2.el6 base 778 k
ttmkfdir x86_64 3.0.9-32.1.el6 base 43 k
tzdata-java noarch 2013i-2.el6 updates 147 k
xorg-x11-font-utils x86_64 1:7.2-11.el6 base 75 k
xorg-x11-fonts-Type1 noarch 7.2-9.1.el6 base 520 k
Transaction Summary
Install 21 Package(s)
Total download size: 29 M
Installed size: 100 M
Is this ok [y/N]: y
Downloading Packages:
(1/21): alsa-lib-1.0.22-3.el6.x86_64.rpm | 370 kB 00:00
(2/21): flac-1.2.1-6.1.el6.x86_64.rpm | 243 kB 00:00
(3/21): giflib-4.1.6-3.1.el6.x86_64.rpm | 37 kB 00:00
(4/21): java-1.7.0-openjdk-1.7.0.51-2.4.4.1.el6_5.x86_64.rpm | 26 MB 00:02
(5/21): jline-0.9.94-0.8.el6.noarch.rpm | 86 kB 00:00
(6/21): jpackage-utils-1.7.5-3.12.el6.noarch.rpm | 59 kB 00:00
(7/21): libICE-1.0.6-1.el6.x86_64.rpm | 53 kB 00:00
(8/21): libSM-1.2.1-2.el6.x86_64.rpm | 37 kB 00:00
(9/21): libXfont-1.4.5-3.el6_5.x86_64.rpm | 136 kB 00:00
(10/21): libXtst-1.2.1-2.el6.x86_64.rpm | 29 kB 00:00
(11/21): libasyncns-0.8-1.1.el6.x86_64.rpm | 24 kB 00:00
(12/21): libfontenc-1.0.5-2.el6.x86_64.rpm | 24 kB 00:00
(13/21): libogg-1.1.4-2.1.el6.x86_64.rpm | 21 kB 00:00
(14/21): libsndfile-1.0.20-5.el6.x86_64.rpm | 233 kB 00:00
(15/21): libvorbis-1.2.3-4.el6_2.1.x86_64.rpm | 168 kB 00:00
(16/21): pulseaudio-libs-0.9.21-14.el6_3.x86_64.rpm | 462 kB 00:00
(17/21): rhino-1.7-0.7.r2.2.el6.noarch.rpm | 778 kB 00:00
(18/21): ttmkfdir-3.0.9-32.1.el6.x86_64.rpm | 43 kB 00:00
(19/21): tzdata-java-2013i-2.el6.noarch.rpm | 147 kB 00:00
(20/21): xorg-x11-font-utils-7.2-11.el6.x86_64.rpm | 75 kB 00:00
(21/21): xorg-x11-fonts-Type1-7.2-9.1.el6.noarch.rpm | 520 kB 00:00
--------------------------------------------------------------------------------------------------
Total 7.2 MB/s | 29 MB 00:04
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
Installing : libICE-1.0.6-1.el6.x86_64 1/21
Installing : 2:libogg-1.1.4-2.1.el6.x86_64 2/21
Installing : libSM-1.2.1-2.el6.x86_64 3/21
Installing : libXtst-1.2.1-2.el6.x86_64 4/21
Installing : jpackage-utils-1.7.5-3.12.el6.noarch 5/21
Installing : alsa-lib-1.0.22-3.el6.x86_64 6/21
Installing : libfontenc-1.0.5-2.el6.x86_64 7/21
Installing : libXfont-1.4.5-3.el6_5.x86_64 8/21
Installing : 1:xorg-x11-font-utils-7.2-11.el6.x86_64 9/21
Installing : giflib-4.1.6-3.1.el6.x86_64 10/21
Installing : flac-1.2.1-6.1.el6.x86_64 11/21
Installing : 1:libvorbis-1.2.3-4.el6_2.1.x86_64 12/21
Installing : libsndfile-1.0.20-5.el6.x86_64 13/21
Installing : libasyncns-0.8-1.1.el6.x86_64 14/21
Installing : pulseaudio-libs-0.9.21-14.el6_3.x86_64 15/21
Installing : jline-0.9.94-0.8.el6.noarch 16/21
Installing : rhino-1.7-0.7.r2.2.el6.noarch 17/21
Installing : tzdata-java-2013i-2.el6.noarch 18/21
Installing : ttmkfdir-3.0.9-32.1.el6.x86_64 19/21
Installing : xorg-x11-fonts-Type1-7.2-9.1.el6.noarch 20/21
Installing : 1:java-1.7.0-openjdk-1.7.0.51-2.4.4.1.el6_5.x86_64 21/21
Verifying : pulseaudio-libs-0.9.21-14.el6_3.x86_64 1/21
Verifying : ttmkfdir-3.0.9-32.1.el6.x86_64 2/21
Verifying : tzdata-java-2013i-2.el6.noarch 3/21
Verifying : libXfont-1.4.5-3.el6_5.x86_64 4/21
Verifying : libfontenc-1.0.5-2.el6.x86_64 5/21
Verifying : flac-1.2.1-6.1.el6.x86_64 6/21
Verifying : jline-0.9.94-0.8.el6.noarch 7/21
Verifying : alsa-lib-1.0.22-3.el6.x86_64 8/21
Verifying : 2:libogg-1.1.4-2.1.el6.x86_64 9/21
Verifying : 1:libvorbis-1.2.3-4.el6_2.1.x86_64 10/21
Verifying : 1:xorg-x11-font-utils-7.2-11.el6.x86_64 11/21
Verifying : xorg-x11-fonts-Type1-7.2-9.1.el6.noarch 12/21
Verifying : libSM-1.2.1-2.el6.x86_64 13/21
Verifying : libICE-1.0.6-1.el6.x86_64 14/21
Verifying : 1:java-1.7.0-openjdk-1.7.0.51-2.4.4.1.el6_5.x86_64 15/21
Verifying : rhino-1.7-0.7.r2.2.el6.noarch 16/21
Verifying : libasyncns-0.8-1.1.el6.x86_64 17/21
Verifying : giflib-4.1.6-3.1.el6.x86_64 18/21
Verifying : libsndfile-1.0.20-5.el6.x86_64 19/21
Verifying : jpackage-utils-1.7.5-3.12.el6.noarch 20/21
Verifying : libXtst-1.2.1-2.el6.x86_64 21/21
Installed:
java-1.7.0-openjdk.x86_64 1:1.7.0.51-2.4.4.1.el6_5
Dependency Installed:
alsa-lib.x86_64 0:1.0.22-3.el6 flac.x86_64 0:1.2.1-6.1.el6
giflib.x86_64 0:4.1.6-3.1.el6 jline.noarch 0:0.9.94-0.8.el6
jpackage-utils.noarch 0:1.7.5-3.12.el6 libICE.x86_64 0:1.0.6-1.el6
libSM.x86_64 0:1.2.1-2.el6 libXfont.x86_64 0:1.4.5-3.el6_5
libXtst.x86_64 0:1.2.1-2.el6 libasyncns.x86_64 0:0.8-1.1.el6
libfontenc.x86_64 0:1.0.5-2.el6 libogg.x86_64 2:1.1.4-2.1.el6
libsndfile.x86_64 0:1.0.20-5.el6 libvorbis.x86_64 1:1.2.3-4.el6_2.1
pulseaudio-libs.x86_64 0:0.9.21-14.el6_3 rhino.noarch 0:1.7-0.7.r2.2.el6
ttmkfdir.x86_64 0:3.0.9-32.1.el6 tzdata-java.noarch 0:2013i-2.el6
xorg-x11-font-utils.x86_64 1:7.2-11.el6 xorg-x11-fonts-Type1.noarch 0:7.2-9.1.el6
Complete!
在centos linux上设置JAVA_HOME environment variable(JAVA_HOME环境变量)
rhel 和 centos linux 使用yum命令后，将 OpenSDK 安装到/usr/lib/jvm/目录：
[root@dabu.info ~]# ls -l /usr/lib/jvm/
输出如下：
total 4
drwxr-xr-x. 3 root root 4096 Feb 24 17:00java-1.7.0-openjdk-1.7.0.51.x86_64
lrwxrwxrwx. 1 root root 21 Feb 24 17:00 jre -> /etc/alternatives/jre
lrwxrwxrwx. 1 root root 27 Feb 24 17:00 jre-1.7.0 -> /etc/alternatives/jre_1.7.0
lrwxrwxrwx. 1 root root 38 Feb 24 17:00 jre-1.7.0-openjdk.x86_64 -> java-1.7.0-openjdk-1.7.0.51.x86_64/jre
lrwxrwxrwx. 1 root root 29 Feb 24 17:00 jre-openjdk -> /etc/alternatives/jre_openjdk
解释：输出的第二行的drwxr-xr-x.中的d表示是文件夹。其余的l表示链接。
设置JAVA_HOME指向一个含有java可执行程序的目录(一般是在bin/java中)。我们用cd 命令进入到jvm下唯一的一个目录中java-1.7.0-openjdk-1.7.0.51.x86_64 ，而jre-1.7.0-openjdk.x86_64 这个链接是指向 java-1.7.0-openjdk-1.7.0.51.x86_64 这个文件夹，所以，可以直接用export命令将 JAVA_HOME 指向 jre-1.7.0-openjdk.x86_64 这个链接。
即使用export命令:
[root@dabu.info ~]# export JAVA_HOME=/usr/lib/jvm/java-1.7.0-openjdk-1.7.0.51.x86_64
但是这样只能在当前会话中有效，一旦注销下线，就失效了。
所以最好保存到$HOME/.bashrc文件中(这个文件是针对指定用户的，如你是叫dabu用户，那么使用dabu用户登陆，然后输入命令：echo $HOME/.bashrc，就会显示你要修改的文件路径)
找到该文件后，在文件底部添加一行，如下：
export JAVA_HOME=/usr/lib/jvm/java-1.7.0-openjdk-1.7.0.51.x86_64
修改后保存关闭文件。
或者让系统上的所有用户使用java(openjdk),则要进行下面的操作：
[root@dabu.info ~]# vi /etc/profile
将下面的三行粘贴到 /etc/profile 中：
export JAVA_HOME=/usr/lib/jvm/java-1.7.0-openjdk-1.7.0.51.x86_64
export CLASSPATH=.:$JAVA_HOME/jre/lib/rt.jar:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
export PATH=$PATH:$JAVA_HOME/bin
保存关闭，后，执行：
[root@dabu.info ~]# source /etc/profile
让设置立即生效。
在输入以下命令，来确认这三个变量是否设成了我们想要的：
[root@dabu.info ~]# echo $JAVA_HOME
[root@dabu.info ~]# echo $CLASSPATH
[root@dabu.info ~]# echo $PATH
测试java是否安装配置成功
查看 java 版本，输入命令：
[root@dabu.info ~]# java -version
创建一个java小程序测试下，名字叫HelloWorld.java，输入以下命令：
[root@dabu.info ~]# touch HelloWorld.java
将以下代码复制到 HelloWorld.java 中 ：
public class HelloWorld {
pu
blic static void main(String[] args) {
System.out.println("Hello,World! This is a test code by nixCraft!");
}
}
复制进去后，保存关闭文件。编译和运行这个小程序，输入以下命令:
[root@dabu.info ~]# javac HelloWorld.java
[root@dabu.info ~]# java HelloWorld
会得到以下显示：
Hello,World! This is a test code by nixCraft!
如何(怎样)运行 .jar 这类java应用？
语法如下：
[root@dabu.info ~]# java -jar file.jar
[root@dabu.info ~]# java -jar /path/to/my/java/app.jar #/path/to/my/java/app.jar表示应用的路径
[root@dabu.info ~]# java -jar /path/to/my/java/app.jar arg1 arg2 # arg1表示参数1 ，arg2表示参数2
参考自《CentOS Install Java SDK using yum Command》,其中关于变量的文章和内容，我修改了下，因为它说的是sun jdk 而不是 openjdk。
