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！
