大家好，又见面了，我是你们的朋友全栈君。
卸载
查看已经安装的jdk
代码语言：javascript复制[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
代码语言：javascript复制[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
代码语言：javascript复制[root@bogon lib]# java -version
bash: java: command not found...安装
去官网下载jdk 解压到安装目录
代码语言：javascript复制[root@bogon software]# tar -zxvf jdk-8u101-linux-x64.tar.gz -C /usr/local/java/安装完毕之后在/etc/profile文件末尾添加
代码语言：javascript复制[root@bogon software]# vim /etc/profile
export JAVA_HOME=/usr/local/java/jdk1.8.0_101
export JRE_HOME=${JAVA_HOME}/jre
export CLASSPATH=.:${JAVA_HOME}/lib:${JRE_HOME}/lib
export PATH=${JAVA_HOME}/bin:$PATH使/etc/profile生效
代码语言：javascript复制[root@bogon jdk1.8.0_101]# source /etc/profile检测安装是否成功
代码语言：javascript复制[root@bogon jdk1.8.0_101]# java -version
java version "1.8.0_101"
Java(TM) SE Runtime Environment (build 1.8.0_101-b13)
Java HotSpot(TM) 64-Bit Server VM (build 25.101-b13, mixed mode)
[root@bogon jdk1.8.0_101]# javac
Usage: javac <options> <source files>
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 <path> Specify where to find user class files and annotation processors -cp <path> Specify where to find user class files and annotation processors -sourcepath <path> Specify where to find input source files -bootclasspath <path> Override location of bootstrap class files -extdirs <dirs> Override location of installed extensions -endorseddirs <dirs> Override location of endorsed standards path -proc:{none,only} Control whether annotation processing and/or compilation is done. -processor <class1>[,<class2>,<class3>...] Names of the annotation processors to run; bypasses default discovery process -processorpath <path> Specify where to find annotation processors -parameters Generate metadata for reflection on method parameters -d <directory> Specify where to place generated class files -s <directory> Specify where to place generated source files -h <directory> Specify where to place generated native header files -implicit:{none,class} Specify whether or not to generate class files for implicitly referenced files -encoding <encoding> Specify character encoding used by source files -source <release> Provide source compatibility with specified release -target <release> Generate class files for specific VM version -profile <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<flag> Pass <flag> directly to the runtime system -Werror Terminate compilation if warnings occur @<filename> Read options and filenames from file发布者：全栈程序员栈长，转载请注明出处：https://javaforall.cn/152994.html原文链接：https://javaforall.cn
