linux 安装JDK

yum 卸载 jdk

yum -y remove java java-1.4.2-gcj-compat-1.4.2.0-40jpp.115

yum 安装的jdk

1. 使用yum查找jdk: yum search java|grep jdk

   

   # yum search java|grep jdkldapjdk-javadoc.noarch : 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-accessibility.x86_64 : OpenJDK accessibility connectorjava-1.7.0-openjdk-demo.x86_64 : OpenJDK Demosjava-1.7.0-openjdk-devel.x86_64 : OpenJDK Development Environmentjava-1.7.0-openjdk-headless.x86_64 : The OpenJDK runtime environment withoutjava-1.7.0-openjdk-javadoc.noarch : OpenJDK API Documentationjava-1.7.0-openjdk-src.x86_64 : OpenJDK Source Bundlejava-1.8.0-openjdk.i686 : OpenJDK Runtime Environmentjava-1.8.0-openjdk.x86_64 : OpenJDK Runtime Environmentjava-1.8.0-openjdk-accessibility.i686 : OpenJDK accessibility connectorjava-1.8.0-openjdk-accessibility.x86_64 : OpenJDK accessibility connectorjava-1.8.0-openjdk-accessibility-debug.i686 : OpenJDK accessibility connectorjava-1.8.0-openjdk-accessibility-debug.x86_64 : OpenJDK accessibility connectorjava-1.8.0-openjdk-debug.i686 : OpenJDK Runtime Environment with full debug onjava-1.8.0-openjdk-debug.x86_64 : OpenJDK Runtime Environment with full debug onjava-1.8.0-openjdk-demo.i686 : OpenJDK Demosjava-1.8.0-openjdk-demo.x86_64 : OpenJDK Demosjava-1.8.0-openjdk-demo-debug.i686 : OpenJDK Demos with full debug onjava-1.8.0-openjdk-demo-debug.x86_64 : OpenJDK Demos with full debug onjava-1.8.0-openjdk-devel.i686 : OpenJDK Development Environmentjava-1.8.0-openjdk-devel.x86_64 : OpenJDK Development Environmentjava-1.8.0-openjdk-devel-debug.i686 : OpenJDK Development Environment with fulljava-1.8.0-openjdk-devel-debug.x86_64 : OpenJDK Development Environment withjava-1.8.0-openjdk-headless.i686 : OpenJDK Runtime Environmentjava-1.8.0-openjdk-headless.x86_64 : OpenJDK Runtime Environmentjava-1.8.0-openjdk-headless-debug.i686 : OpenJDK Runtime Environment with fulljava-1.8.0-openjdk-headless-debug.x86_64 : OpenJDK Runtime Environment with fulljava-1.8.0-openjdk-javadoc.noarch : OpenJDK API Documentationjava-1.8.0-openjdk-javadoc-debug.noarch : OpenJDK API Documentation for packagesjava-1.8.0-openjdk-javadoc-zip.noarch : OpenJDK API Documentation compressed injava-1.8.0-openjdk-javadoc-zip-debug.noarch : OpenJDK API Documentationjava-1.8.0-openjdk-src.i686 : OpenJDK Source Bundlejava-1.8.0-openjdk-src.x86_64 : OpenJDK Source Bundlejava-1.8.0-openjdk-src-debug.i686 : OpenJDK Source Bundle for packages withjava-1.8.0-openjdk-src-debug.x86_64 : OpenJDK Source Bundle for packages withjava-11-openjdk.i686 : OpenJDK Runtime Environment 11java-11-openjdk.x86_64 : OpenJDK Runtime Environment 11java-11-openjdk-debug.i686 : OpenJDK Runtime Environment 11 with full debug onjava-11-openjdk-debug.x86_64 : OpenJDK Runtime Environment 11 with full debug onjava-11-openjdk-demo.i686 : OpenJDK Demos 11java-11-openjdk-demo.x86_64 : OpenJDK Demos 11java-11-openjdk-demo-debug.i686 : OpenJDK Demos 11 with full debug onjava-11-openjdk-demo-debug.x86_64 : OpenJDK Demos 11 with full debug onjava-11-openjdk-devel.i686 : OpenJDK Development Environment 11java-11-openjdk-devel.x86_64 : OpenJDK Development Environment 11java-11-openjdk-devel-debug.i686 : OpenJDK Development Environment 11 with fulljava-11-openjdk-devel-debug.x86_64 : OpenJDK Development Environment 11 withjava-11-openjdk-headless.i686 : OpenJDK Headless Runtime Environment 11java-11-openjdk-headless.x86_64 : OpenJDK Headless Runtime Environment 11java-11-openjdk-headless-debug.i686 : OpenJDK Runtime Environment with fulljava-11-openjdk-headless-debug.x86_64 : OpenJDK Runtime Environment with fulljava-11-openjdk-javadoc.i686 : OpenJDK 11 API documentationjava-11-openjdk-javadoc.x86_64 : OpenJDK 11 API documentationjava-11-openjdk-javadoc-debug.i686 : OpenJDK 11 API documentation for packagesjava-11-openjdk-javadoc-debug.x86_64 : OpenJDK 11 API documentation for packagesjava-11-openjdk-javadoc-zip.i686 : OpenJDK 11 API documentation compressed injava-11-openjdk-javadoc-zip.x86_64 : OpenJDK 11 API documentation compressed injava-11-openjdk-javadoc-zip-debug.i686 : OpenJDK 11 API documentation compressedjava-11-openjdk-javadoc-zip-debug.x86_64 : OpenJDK 11 API documentationjava-11-openjdk-jmods.i686 : JMods for OpenJDK 11java-11-openjdk-jmods.x86_64 : JMods for OpenJDK 11java-11-openjdk-jmods-debug.i686 : JMods for OpenJDK 11 with full debug onjava-11-openjdk-jmods-debug.x86_64 : JMods for OpenJDK 11 with full debug onjava-11-openjdk-src.i686 : OpenJDK Source Bundle 11java-11-openjdk-src.x86_64 : OpenJDK Source Bundle 11java-11-openjdk-src-debug.i686 : OpenJDK Source Bundle for packages with debugjava-11-openjdk-src-debug.x86_64 : OpenJDK Source Bundle 11 for packages withldapjdk.noarch : The Mozilla LDAP Java SDK

   

2. 执行安装命令：yum install java-1.8.0-openjdk

   安装成功后，默认安装路径在/usr/lib/jvm/下边，
   如/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.144-0.b01.el6_9.x86_64

   查看安装路径(如下所示)：
   which java
   ls -lrt /usr/bin/java

   

   [root@preproduct1 ~]# which java/usr/bin/java[root@preproduct1 ~]# echo $JAVA_HOME/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.191.b12-1.el7_6.x86_64[root@preproduct1 ~]# ls -lrt /usr/bin/javalrwxrwxrwx 1 root root 22 Feb 13 10:40 /usr/bin/java -> /etc/alternatives/java[root@preproduct1 ~]# ls -lrt /etc/alternatives/javalrwxrwxrwx 1 root root 73 Feb 13 10:40 /etc/alternatives/java -> /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.191.b12-1.el7_6.x86_64/jre/bin/java[root@preproduct1 ~]# cd /usr/lib/jvm[root@preproduct1 /usr/lib/jvm]# lltotal 4lrwxrwxrwx 1 root root   26 Feb 13 10:44 java -> /etc/alternatives/java_sdklrwxrwxrwx 1 root root   32 Feb 13 10:44 java-1.8.0 -> /etc/alternatives/java_sdk_1.8.0lrwxrwxrwx 1 root root   40 Feb 13 10:44 java-1.8.0-openjdk -> /etc/alternatives/java_sdk_1.8.0_openjdkdrwxr-xr-x 7 root root 4096 Feb 13 10:44 java-1.8.0-openjdk-1.8.0.191.b12-1.el7_6.x86_64lrwxrwxrwx 1 root root   34 Feb 13 10:44 java-openjdk -> /etc/alternatives/java_sdk_openjdklrwxrwxrwx 1 root root   21 Feb 13 10:40 jre -> /etc/alternatives/jrelrwxrwxrwx 1 root root   27 Feb 13 10:40 jre-1.8.0 -> /etc/alternatives/jre_1.8.0lrwxrwxrwx 1 root root   35 Feb 13 10:40 jre-1.8.0-openjdk -> /etc/alternatives/jre_1.8.0_openjdklrwxrwxrwx 1 root root   51 Feb 13 10:40 jre-1.8.0-openjdk-1.8.0.191.b12-1.el7_6.x86_64 -> java-1.8.0-openjdk-1.8.0.191.b12-1.el7_6.x86_64/jrelrwxrwxrwx 1 root root   29 Feb 13 10:40 jre-openjdk -> /etc/alternatives/jre_openjdk

   

3. 验证java是否安装成功

• 查看java版本：java -version

  # java -versionopenjdk version "1.8.0_191"OpenJDK Runtime Environment (build 1.8.0_191-b12)OpenJDK 64-Bit Server VM (build 25.191-b12, mixed mode)

• 查看java是否可用：javac

  # javac-bash: javac: command not found

  错误原因：默认安装完只有运行环境，java安装目录下只有jre文件夹

4. 安装开发环境yum install java-1.8.0-openjdk-devel.x86_64
   安装完可看到java安装目录下出现bin、lib等文件夹:

   

   [root@preproduct1 /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.191.b12-1.el7_6.x86_64]# ltotal 20drwxr-xr-x 2 root root 4096 Feb 13 10:44 bindrwxr-xr-x 3 root root 4096 Feb 13 10:44 includedrwxr-xr-x 4 root root 4096 Feb 13 10:40 jredrwxr-xr-x 3 root root 4096 Feb 13 10:44 libdrwxr-xr-x 2 root root 4096 Feb 13 10:44 tapset

   

   再次输入javac说明安装成功

   

   # javacUsage: 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 use  -classpath <path>          Specify where to find user class files and annotationocessors  -cp <path>                 Specify where to find user class files and annotationocessors  -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 compilat is done.  -processor <class1>[,<class2>,<class3>...] Names of the annotation processors ton; 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 imcitly 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 proe  -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

   

5. 设置环境变量
   修改/etc/profile文件：vi /etc/profile
   在profile文件末尾新增如下内容：

   #set java environment   JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.191.b12-1.el7_6.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

   使环境变量生效：source /etc/profile

   [root@preproduct1 /usr/lib/jvm]# cd /usr/lib/jvm[root@preproduct1 /usr/lib/jvm]# cd java-1.8.0-openjdk-1.8.0.191.b12-1.el7_6.x86_64/[root@preproduct1 /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.191.b12-1.el7_6.x86_64]# source /etc/profile[root@preproduct1 /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.191.b12-1.el7_6.x86_64]# echo $JAVA_HOME/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.191.b12-1.el7_6.x86_64

yum 安装 jdk

yum install java-1.8.0-openjdk* -y

1、which java

首先输入命令行，查看结果：

 [root@localhost ~]# which java

 /usr/bin/java 

PS：which Java是无法定位到Java的安装路径的，只能定位到执行路径；whereis Java也无法定位，只能展示一部分的Java路径，如下所示：

 [root@localhost ~]# whereis java

 java: /usr/bin/java /usr/lib/java /etc/java /usr/share/java /usr/share/man/man1/java.1.gz 

2、echo $JAVA_HOME

使用 echo $JAVA_HOME 命令可以定位到Java安装路径，但是前提是配置了环境变量$JAVA_HOME，否则还是定位不到，如下所示：

[root@localhost ~]# java -versionopenjdk version "1.8.0_161"OpenJDK Runtime Environment (build 1.8.0_161-b14)OpenJDK 64-Bit Server VM (build 25.161-b14, mixed mode)[root@localhost ~]# echo $JAVA_HOME[root@localhost ~]#

3、rpm -qa | grep java

如果JDK是源码安装，那么rpm -qa | grep java命令也是定位不到的jdk的安装路径的，比如我是用的yum命令安装，使用rpm -qa | grep java命令的话，结果如下所示：

[root@localhost ~]# rpm -qa | grep javajavapackages-tools-3.4.1-11.el7.noarchjava-1.8.0-openjdk-headless-1.8.0.161-0.b14.el7_4.x86_64tzdata-java-2018d-1.el7.noarchjava-1.8.0-openjdk-devel-1.8.0.161-0.b14.el7_4.x86_64java-1.8.0-openjdk-1.8.0.161-0.b14.el7_4.x86_64java-1.7.0-openjdk-1.7.0.171-2.6.13.0.el7_4.x86_64python-javapackages-3.4.1-11.el7.noarchjava-1.7.0-openjdk-headless-1.7.0.171-2.6.13.0.el7_4.x86_64[root@localhost ~]# 

4、ls -lrt

先了解下ls命令：

-a 显示所有文件及目录 (ls内定将文件名或目录名称开头为"."的视为隐藏档，不会列出) -l 除文件名称外，亦将文件型态、权限、拥有者、文件大小等资讯详细列出 -r 将文件以相反次序显示(原定依英文字母次序) -t 将文件依建立时间之先后次序列出 -A 同 -a ，但不列出 "." (目前目录) 及 ".." (父目录) -F 在列出的文件名称后加一符号；例如可执行档则加 "*", 目录则加 "/" -R 若目录下有文件，则以下之文件亦皆依序列出

根据上面的命令，我们可以执行如下命令，找到JDK的安装路径：

[root@localhost ~]# ls -lrt /usr/bin/javalrwxrwxrwx 1 root root 22 Apr  3 19:30 /usr/bin/java -> /etc/alternatives/java[root@localhost ~]# ls -lrt /etc/alternatives/javalrwxrwxrwx 1 root root 73 Apr  3 19:30 /etc/alternatives/java -> /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.161-0.b14.el7_4.x86_64/jre/bin/java[root@localhost ~]# cd /usr/lib/jvm[root@localhost ~]# lsjava                                                jre-1.7.0java-1.7.0-openjdk-1.7.0.171-2.6.13.0.el7_4.x86_64  jre-1.7.0-openjdkjava-1.8.0                                          jre-1.7.0-openjdk-1.7.0.171-2.6.13.0.el7_4.x86_64java-1.8.0-openjdk                                  jre-1.8.0java-1.8.0-openjdk-1.8.0.161-0.b14.el7_4.x86_64     jre-1.8.0-openjdkjava-openjdk                                        jre-1.8.0-openjdk-1.8.0.161-0.b14.el7_4.x86_64jre                                                 jre-openjdk

ls -lrt解析：即将文件以建立时间先后顺序的倒叙排列显示，从上面的结果可以看出，/usr/bin/java是执行路径，那么继续执行后面的文件路径，即可找到JDK的安装路径为/usr/lib/jvm/java-1.8.0。

PS：上面提到的几种方法，适用于安装在Linux上的软件查询路径使用（并不仅仅限于查找JDK安装路径），请选择合适的方法。。。

转自：https://www.cnblogs.com/imyalost/p/8745137.html