用yum安装JDK
-1.查看是否安装了jdk
[root@localhost java]# java -version
bash: java: command not found
1.查看yum库中都有哪些jdk版本(暂时只发现了openjdk)
[root@localhost ~]# yum search java|grep jdk
ldapjdk-javadoc.x86_64 : Javadoc for ldapjdk
java-1.6.0-openjdk.x86_64 : OpenJDK Runtime Environment
java-1.6.0-openjdk-demo.x86_64 : OpenJDK Demos
java-1.6.0-openjdk-devel.x86_64 : OpenJDK Development Environment
java-1.6.0-openjdk-javadoc.x86_64 : OpenJDK API Documentation
java-1.6.0-openjdk-src.x86_64 : OpenJDK Source Bundle
java-1.7.0-openjdk.x86_64 : OpenJDK Runtime Environment
java-1.7.0-openjdk-demo.x86_64 : OpenJDK Demos
java-1.7.0-openjdk-devel.x86_64 : OpenJDK Development Environment
java-1.7.0-openjdk-javadoc.noarch : OpenJDK API Documentation
java-1.7.0-openjdk-src.x86_64 : OpenJDK Source Bundle
java-1.8.0-openjdk.x86_64 : OpenJDK Runtime Environment
java-1.8.0-openjdk-demo.x86_64 : OpenJDK Demos
java-1.8.0-openjdk-devel.x86_64 : OpenJDK Development Environment
java-1.8.0-openjdk-headless.x86_64 : OpenJDK Runtime Environment
java-1.8.0-openjdk-javadoc.noarch : OpenJDK API Documentation
java-1.8.0-openjdk-src.x86_64 : OpenJDK Source Bundle
ldapjdk.x86_64 : The Mozilla LDAP Java SDK
2.选择版本,进行安装
//选择1.7版本进行安装
[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
[root@localhost ~]# vi /etc/profile
在profile文件中添加如下内容
#set java environment
JAVA_HOME=/usr/lib/jvm/java-1.7.0-openjdk-1.7.0.75.x86_64
JRE_HOME=$JAVA_HOME/jre
CLASS_PATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar:$JRE_HOME/lib
PATH=$PATH:$JAVA_HOME/bin:$JRE_HOME/bin
export JAVA_HOME JRE_HOME CLASS_PATH PATH
让修改生效
[root@localhost java]# source /etc/profile
4.验证
[root@localhost java]# java -version
java version “1.7.0_181”
OpenJDK Runtime Environment (rhel-2.6.14.8.el6_9-x86_64 u181-b00)
OpenJDK 64-Bit Server VM (build 24.181-b00, mixed mode)