环境
Linux版本：CentOS 6.5、Ubuntu 12.04.5
JDK版本：JDK 1.7
目录
方法一：手动解压JDK的压缩包，然后设置环境变量
方法二：用yum安装JDK
方法三：用rpm安装JDK
方法四：Ubuntu 上使用apt-get安装JDK
内容
方法一：手动解压JDK的压缩包，然后设置环境变量
1.在/usr/目录下创建java目录
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[root@localhost ~]# mkdir/usr/java[root@localhost ~]# cd /usr/java |
2.下载，然后解压
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[root@localhost java]# curl -O http://download.oracle.com/otn-pub/java/jdk/7u79-b15/jdk-7u79-linux-x64.tar.gz [root@localhost java]# tar -zxvf jdk-7u79-linux-x64.tar.gz |
3.设置环境变量
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[root@localhost java]# vi /etc/profile |
添加如下内容：
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#set java environmentJAVA_HOME=/usr/java/jdk1.7.0_79JRE_HOME=/usr/java/jdk1.7.0_79/jreCLASS_PATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar:$JRE_HOME/libPATH=$PATH:$JAVA_HOME/bin:$JRE_HOME/binexport JAVA_HOME JRE_HOME CLASS_PATH PATH |
让修改生效：
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[root@localhost java]# source /etc/profile |
4.验证
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[root@localhost java]# java -versionjava version "1.7.0_79"Java(TM) SE Runtime Environment (build 1.7.0_79-b15)Java HotSpot(TM) 64-Bit Server VM (build 24.79-b02, mixed mode) |
方法二：用yum安装JDK(CentOS)
1.查看yum库中都有哪些jdk版本
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[root@localhost ~]# yum search java|grep jdkldapjdk-javadoc.x86_64 : Javadoc for ldapjdkjava-1.6.0-openjdk.x86_64 : OpenJDK Runtime Environmentjava-1.6.0-openjdk-demo.x86_64 : OpenJDK Demosjava-1.6.0-openjdk-devel.x86_64 : OpenJDK Development Environmentjava-1.6.0-openjdk-javadoc.x86_64 : OpenJDK API Documentationjava-1.6.0-openjdk-src.x86_64 : OpenJDK Source Bundlejava-1.7.0-openjdk.x86_64 : OpenJDK Runtime Environmentjava-1.7.0-openjdk-demo.x86_64 : OpenJDK Demosjava-1.7.0-openjdk-devel.x86_64 : OpenJDK Development Environmentjava-1.7.0-openjdk-javadoc.noarch : OpenJDK API Documentationjava-1.7.0-openjdk-src.x86_64 : OpenJDK Source Bundlejava-1.8.0-openjdk.x86_64 : OpenJDK Runtime Environmentjava-1.8.0-openjdk-demo.x86_64 : OpenJDK Demosjava-1.8.0-openjdk-devel.x86_64 : OpenJDK Development Environmentjava-1.8.0-openjdk-headless.x86_64 : OpenJDK Runtime Environmentjava-1.8.0-openjdk-javadoc.noarch : OpenJDK API Documentationjava-1.8.0-openjdk-src.x86_64 : OpenJDK Source Bundleldapjdk.x86_64 : The Mozilla LDAP Java SDK |
2.选择版本，进行安装，我们这里安装1.7版本
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[root@localhost ~]# yum install java-1.7.0-openjdk |
安装完之后，默认的安装目录是在: /usr/lib/jvm/java-1.7.0-openjdk-1.7.0.75.x86_64
3.设置环境变量
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[root@localhost ~]# vi /etc/profile |
添加如下内容：
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#set java environmentJAVA_HOME=/usr/lib/jvm/java-1.7.0-openjdk-1.7.0.75.x86_64JRE_HOME=$JAVA_HOME/jreCLASS_PATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar:$JRE_HOME/libPATH=$PATH:$JAVA_HOME/bin:$JRE_HOME/binexport JAVA_HOME JRE_HOME CLASS_PATH PATH |
让修改生效：
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[root@localhost java]# source /etc/profile |
3.验证 同上。
注：因为采用yum安装jdk，系统考虑到多版本的问题，会用alternatives进行版本控制。开始，相应版本的jdk安装在/usr/lib/jvm/之后，会在alternatives中注册，在/etc/alternatives目录下会产生一些链接到/usr/lib/jvm/中刚安装好的jdk版本。
在/usr/bin下面会有链接到/etc/alternatives的相应的文件。比如，/usr/bin下面会有一个链接文件java的映射关系如下：
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/usr/bin/java->/etc/alternatives/java/etc/alternatives/java-> /usr/lib/jvm/jre-1.7.0-openjdk.x86_64/bin/java |
这样，java命令不用设置环境变量，就可以正常运行了。但如果对于tomcat或其他软件来说还是要设置环境变量。
同样，如果安装新的版本jdk，就会重新链接到最新安装的jdk版本。当然，也可以使用alternatives修改所要使用的版本。
具体方法可参照：《使用Linux的alternatives管理多版本的软件》
方法三：用rpm安装JDK
1.下载
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[hadoop@localhost ~]$ curl -O http://download.oracle.com/otn-pub/java/jdk/7u79-b15/jdk-7u79-linux-x64.rpm |
2.使用rpm命令安装
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[root@localhost ~]# rpm -ivh jdk-7u79-linux-x64.rpmPreparing... ########################################### [100%] 1:jdk ###########################################[100%]Unpacking JAR files... rt.jar... jsse.jar... charsets.jar... tools.jar... localedata.jar... jfxrt.jar... |
3.设置环境变量
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[root@localhost java]# vi /etc/profile |
添加如下内容：
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#set java environmentJAVA_HOME=/usr/java/jdk1.7.0_79JRE_HOME=/usr/java/jdk1.7.0_79/jreCLASS_PATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar:$JRE_HOME/libPATH=$PATH:$JAVA_HOME/bin:$JRE_HOME/binexport JAVA_HOME JRE_HOME CLASS_PATH PATH |
让修改生效：
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[root@localhost java]# source /etc/profile |
4.验证
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[root@localhost java]# java -versionjava version "1.7.0_79"Java(TM) SE Runtime Environment (build 1.7.0_79-b15)Java HotSpot(TM) 64-Bit Server VM (build 24.79-b02, mixed mode) |
和yum安装类似，不用设置环境变量就可以，运行java命令。rpm安装方式默认会把jdk安装到/usr/java/jdk1.7.0_79，然后通过三层链接，链接到/usr/bin,具体链接如下：
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[root@localhost ~]# cd /bin[root@localhost bin]# ll|grep javalrwxrwxrwx. 1 root root 25 Mar 28 11:24 jar ->/usr/java/default/bin/jarlrwxrwxrwx. 1 root root 26 Mar 28 11:24 java -> /usr/java/default/bin/javalrwxrwxrwx. 1 root root 27 Mar 28 11:24 javac ->/usr/java/default/bin/javaclrwxrwxrwx. 1 root root 29 Mar 28 11:24 javadoc ->/usr/java/default/bin/javadoclrwxrwxrwx. 1 root root 28 Mar 28 11:24 javaws ->/usr/java/default/bin/javawslrwxrwxrwx. 1 root root 30 Mar 28 11:24 jcontrol ->/usr/java/default/bin/jcontrol[root@localhost bin]# cd /usr/java/[root@localhost java]# lltotal 4lrwxrwxrwx. 1 root root 16 Mar 28 11:24 default-> /usr/java/latestdrwxr-xr-x. 8 root root 4096 Mar 28 11:24 jdk1.7.0_79lrwxrwxrwx. 1 root root 21 Mar 28 11:24 latest -> /usr/java/jdk1.7.0_79 |
方法四：Ubuntu 上使用apt-get安装JDK
1.查看apt库都有哪些jdk版本
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root@Itble:~# apt-cache search java|grep jdkdefault-jdk - Standard Java or Java compatible Development Kitdefault-jdk-doc - Standard Java or Java compatible Development Kit (documentation)gcj-4.6-jdk - gcj and classpath development tools for Java(TM)gcj-jdk - gcj and classpath development tools for Java(TM)openjdk-6-dbg - Java runtime based on OpenJDK (debugging symbols)openjdk-6-demo - Java runtime based on OpenJDK (demos and examples)openjdk-6-doc - OpenJDK Development Kit (JDK) documentationopenjdk-6-jdk - OpenJDK Development Kit (JDK)openjdk-6-jre-lib - OpenJDK Java runtime (architecture independent libraries)openjdk-6-source - OpenJDK Development Kit (JDK) source filesopenjdk-7-dbg - Java runtime based on OpenJDK (debugging symbols)openjdk-7-demo - Java runtime based on OpenJDK (demos and examples)openjdk-7-doc - OpenJDK Development Kit (JDK) documentationopenjdk-7-jdk - OpenJDK Development Kit (JDK)openjdk-7-source - OpenJDK Development Kit (JDK) source filesuwsgi-plugin-jvm-openjdk-6 - Java plugin for uWSGI (OpenJDK 6)uwsgi-plugin-jwsgi-openjdk-6 - JWSGI plugin for uWSGI (OpenJDK 6)openjdk-6-jre - OpenJDK Java runtime, using Hotspot JITopenjdk-6-jre-headless - OpenJDK Java runtime, using Hotspot JIT (headless)openjdk-7-jre - OpenJDK Java runtime, using Hotspot JITopenjdk-7-jre-headless - OpenJDK Java runtime, using Hotspot JIT (headless)openjdk-7-jre-lib - OpenJDK Java runtime (architecture independent libraries) |
2.选择版本进行安装
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root@Itble:~# apt-get install openjdk-7-jdk |
3.设置环境变量
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root@Itble:~# vi /etc/profile |
添加如下内容：
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#set java environmentJAVA_HOME=/usr/lib/jvm/java-1.7.0-openjdk-amd64JRE_HOME=$JAVA_HOME/jreCLASS_PATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar:$JRE_HOME/libPATH=$PATH:$JAVA_HOME/bin:$JRE_HOME/binexport JAVA_HOME JRE_HOME CLASS_PATH PATH |
让修改生效：
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root@Itble:~# source /etc/profile |
4.验证
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root@Itble:~# java -versionjava version "1.7.0_79"OpenJDK Runtime Environment (IcedTea 2.5.5) (7u79-2.5.5-0ubuntu0.12.04.1)OpenJDK 64-Bit Server VM (build 24.79-b02, mixed mode) |
Ubuntu的apt-get安装方式和CentOS的yum安装方式很类似，这里就不再啰嗦。
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。
