cnetos7下卸载openjdk和安装jdk1.8

卸载

[root@bogon jre]# rpm -qa|grep jdk
java-1.8.0-openjdk-headless-1.8.0.65-3.b17.el7.x86_64
java-1.7.0-openjdk-1.7.0.91-2.6.2.3.el7.x86_64
java-1.7.0-openjdk-headless-1.7.0.91-2.6.2.3.el7.x86_64
java-1.8.0-openjdk-1.8.0.65-3.b17.el7.x86_64

卸载命令：

[root@bogon jre]# yum -y remove java-1.8.0-openjdk-headless-1.8.0.65-3.b17.el7.x86_64

卸载完成之后Java命令不被识别

[root@bogon lib]# java -version
bash: java: command not found...

安装

去官网下载jdk：http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html
解压到安装目录

[root@bogon software]# tar -zxvf /jdk1.8.0_161-linux-x64.tar.gz -C /usr/local/java/

安装完毕之后在/etc/profile文件末尾添加

[root@bogon software]# vim /etc/profile
export JAVA_HOME=/usr/local/java/jdk1.8.0_161
export JRE_HOME=${JAVA_HOME}/jre
export CLASSPATH=${JAVA_HOME}/lib:${JRE_HOME}/lib:$CLASSPATH
export PATH=${JAVA_HOME}/bin:${JRE_HOME}/bin:$PATH

使/etc/profile生效

root@bogon jdk1.8.0_101]# source /etc/profile

检测安装是否成功

[root@localhost java]# source /etc/profile
[root@localhost java]# java -version
java version "1.8.0_161"
Java(TM) SE Runtime Environment (build 1.8.0_161-b12)
Java HotSpot(TM) 64-Bit Server VM (build 25.161-b12, mixed mode)
[root@localhost java]# javac
Usage: javac  
where possible options include:
  -g                         Generate all debugging info
  -g:none                    Generate no debugging info
  -g:{lines,vars,source}     Generate only some debugging info
  -nowarn                    Generate no warnings
  -verbose                   Output messages about what the compiler is doing
  -deprecation               Output source locations where deprecated APIs are used
  -classpath           Specify where to find user class files and annotation processors
  -cp                  Specify where to find user class files and annotation processors
  -sourcepath          Specify where to find input source files
  -bootclasspath       Override location of bootstrap class files
  -extdirs             Override location of installed extensions
  -endorseddirs        Override location of endorsed standards path
  -proc:{none,only}          Control whether annotation processing and/or compilation is done.
  -processor [,,...] Names of the annotation processors to run; bypasses default discovery process
  -processorpath       Specify where to find annotation processors
  -parameters                Generate metadata for reflection on method parameters
  -d              Specify where to place generated class files
  -s              Specify where to place generated source files
  -h              Specify where to place generated native header files
  -implicit:{none,class}     Specify whether or not to generate class files for implicitly referenced files
  -encoding        Specify character encoding used by source files
  -source           Provide source compatibility with specified release
  -target           Generate class files for specific VM version
  -profile          Check that API used is available in the specified profile
  -version                   Version information
  -help                      Print a synopsis of standard options
  -Akey[=value]              Options to pass to annotation processors
  -X                         Print a synopsis of nonstandard options
  -J                   Pass  directly to the runtime system
  -Werror                    Terminate compilation if warnings occur
  @                Read options and filenames from file