linux下安装jdk

1、使用yum查找jdk

yum search java|grep jdk

[root@node1 ~]# yum search java|grep jdk
ldapjdk-javadoc.noarch : 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-accessibility.x86_64 : OpenJDK accessibility connector
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-headless.x86_64 : The OpenJDK runtime environment without
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.i686 : OpenJDK Runtime Environment 8
java-1.8.0-openjdk-accessibility.i686 : OpenJDK accessibility connector
java-1.8.0-openjdk-accessibility.x86_64 : OpenJDK accessibility connector
java-1.8.0-openjdk-accessibility-debug.i686 : OpenJDK 8 accessibility connector
java-1.8.0-openjdk-accessibility-debug.x86_64 : OpenJDK 8 accessibility
java-1.8.0-openjdk-debug.i686 : OpenJDK Runtime Environment 8 with full debug on
java-1.8.0-openjdk-debug.x86_64 : OpenJDK Runtime Environment 8 with full debug
java-1.8.0-openjdk-demo.i686 : OpenJDK Demos 8
java-1.8.0-openjdk-demo.x86_64 : OpenJDK Demos 8
java-1.8.0-openjdk-demo-debug.i686 : OpenJDK Demos 8 with full debug on
java-1.8.0-openjdk-demo-debug.x86_64 : OpenJDK Demos 8 with full debug on
java-1.8.0-openjdk-devel.x86_64 : OpenJDK Development Environment
java-1.8.0-openjdk-devel.i686 : OpenJDK Development Environment 8
java-1.8.0-openjdk-devel-debug.i686 : OpenJDK Development Environment 8 with
java-1.8.0-openjdk-devel-debug.x86_64 : OpenJDK Development Environment 8 with
java-1.8.0-openjdk-headless.x86_64 : OpenJDK Runtime Environment
java-1.8.0-openjdk-headless.i686 : OpenJDK Headless Runtime Environment 8
java-1.8.0-openjdk-headless-debug.i686 : OpenJDK Runtime Environment with full
java-1.8.0-openjdk-headless-debug.x86_64 : OpenJDK Runtime Environment with full
java-1.8.0-openjdk-javadoc.noarch : OpenJDK 8 API documentation
java-1.8.0-openjdk-javadoc-debug.noarch : OpenJDK 8 API documentation for
java-1.8.0-openjdk-javadoc-zip.noarch : OpenJDK 8 API documentation compressed
java-1.8.0-openjdk-javadoc-zip-debug.noarch : OpenJDK 8 API documentation
java-1.8.0-openjdk-src.i686 : OpenJDK Source Bundle 8
java-1.8.0-openjdk-src.x86_64 : OpenJDK Source Bundle 8
java-1.8.0-openjdk-src-debug.i686 : OpenJDK Source Bundle 8 for packages with
java-1.8.0-openjdk-src-debug.x86_64 : OpenJDK Source Bundle 8 for packages with
java-11-openjdk.x86_64 : OpenJDK Runtime Environment 11
java-11-openjdk.i686 : OpenJDK Runtime Environment 11
java-11-openjdk-debug.i686 : OpenJDK Runtime Environment 11 with full debug on
java-11-openjdk-debug.x86_64 : OpenJDK Runtime Environment 11 with full debug on
java-11-openjdk-demo.i686 : OpenJDK Demos 11
java-11-openjdk-demo.x86_64 : OpenJDK Demos 11
java-11-openjdk-demo-debug.i686 : OpenJDK Demos 11 with full debug on
java-11-openjdk-demo-debug.x86_64 : OpenJDK Demos 11 with full debug on
java-11-openjdk-devel.i686 : OpenJDK Development Environment 11
java-11-openjdk-devel.x86_64 : OpenJDK Development Environment 11
java-11-openjdk-devel-debug.i686 : OpenJDK Development Environment 11 with full
java-11-openjdk-devel-debug.x86_64 : OpenJDK Development Environment 11 with
java-11-openjdk-headless.x86_64 : OpenJDK Headless Runtime Environment 11
java-11-openjdk-headless.i686 : OpenJDK Headless Runtime Environment 11
java-11-openjdk-headless-debug.i686 : OpenJDK Runtime Environment with full
java-11-openjdk-headless-debug.x86_64 : OpenJDK Runtime Environment with full
java-11-openjdk-javadoc.i686 : OpenJDK 11 API documentation
java-11-openjdk-javadoc.x86_64 : OpenJDK 11 API documentation
java-11-openjdk-javadoc-debug.i686 : OpenJDK 11 API documentation for packages
java-11-openjdk-javadoc-debug.x86_64 : OpenJDK 11 API documentation for packages
java-11-openjdk-javadoc-zip.i686 : OpenJDK 11 API documentation compressed in
java-11-openjdk-javadoc-zip.x86_64 : OpenJDK 11 API documentation compressed in
java-11-openjdk-javadoc-zip-debug.i686 : OpenJDK 11 API documentation compressed
java-11-openjdk-javadoc-zip-debug.x86_64 : OpenJDK 11 API documentation
java-11-openjdk-jmods.i686 : JMods for OpenJDK 11
java-11-openjdk-jmods.x86_64 : JMods for OpenJDK 11
java-11-openjdk-jmods-debug.i686 : JMods for OpenJDK 11 with full debug on
java-11-openjdk-jmods-debug.x86_64 : JMods for OpenJDK 11 with full debug on
java-11-openjdk-src.i686 : OpenJDK Source Bundle 11
java-11-openjdk-src.x86_64 : OpenJDK Source Bundle 11
java-11-openjdk-src-debug.i686 : OpenJDK Source Bundle 11 for packages with
java-11-openjdk-src-debug.x86_64 : OpenJDK Source Bundle 11 for packages with
java-latest-openjdk.x86_64 : OpenJDK Runtime Environment 13
java-latest-openjdk-debug.x86_64 : OpenJDK Runtime Environment 13 with full
java-latest-openjdk-demo.x86_64 : OpenJDK Demos 13
java-latest-openjdk-demo-debug.x86_64 : OpenJDK Demos 13 with full debug on
java-latest-openjdk-devel.x86_64 : OpenJDK Development Environment 13
java-latest-openjdk-devel-debug.x86_64 : OpenJDK Development Environment 13 with
java-latest-openjdk-headless.x86_64 : OpenJDK Headless Runtime Environment 13
java-latest-openjdk-headless-debug.x86_64 : OpenJDK Runtime Environment with
java-latest-openjdk-javadoc.x86_64 : OpenJDK 13 API documentation
java-latest-openjdk-javadoc-zip.x86_64 : OpenJDK 13 API documentation compressed
java-latest-openjdk-jmods.x86_64 : JMods for OpenJDK 13
java-latest-openjdk-jmods-debug.x86_64 : JMods for OpenJDK 13 with full debug on
java-latest-openjdk-src.x86_64 : OpenJDK Source Bundle 13
java-latest-openjdk-src-debug.x86_64 : OpenJDK Source Bundle 13 for packages
ldapjdk.noarch : The Mozilla LDAP Java SDK

2、执行安装命令：

yum install java-1.8.0-openjdk

3、安装成功后，默认安装路径在

/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.232.b09-0.el7_7.x86_64

4、验证java是否安装成功

查看java版本：java -version

[root@node1 ~]# java -version
openjdk version "1.8.0_232"
OpenJDK Runtime Environment (build 1.8.0_232-b09)
OpenJDK 64-Bit Server VM (build 25.232-b09, mixed mode)

查看java是否可用：javac

[root@node1 ~]# 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

5、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:

6、再次输入javac验证是否成功

[root@node1 ~]# 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

7、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-1.8.0.232.b09-0.el7_7.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

8、使环境变量生效：

source /etc/profile

9、查看环境变量

echo $JAVA_HOME查看环境变量

[root@node1 ~]# echo $JAVA_HOME
/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.232.b09-0.el7_7.x86_64

到此结束，完成！