linux 上使用yum 安装openjdk1.8

linux 上使用yum 安装openjdk1.8

• 使用yum查找jdk: yum search java|grep jdk

  # 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.i686 : OpenJDK Runtime Environment
  java-1.8.0-openjdk.x86_64 : OpenJDK Runtime Environment
  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 accessibility connector
  java-1.8.0-openjdk-accessibility-debug.x86_64 : OpenJDK accessibility connector
  java-1.8.0-openjdk-debug.i686 : OpenJDK Runtime Environment with full debug on
  java-1.8.0-openjdk-debug.x86_64 : OpenJDK Runtime Environment with full debug on
  java-1.8.0-openjdk-demo.i686 : OpenJDK Demos
  java-1.8.0-openjdk-demo.x86_64 : OpenJDK Demos
  java-1.8.0-openjdk-demo-debug.i686 : OpenJDK Demos with full debug on
  java-1.8.0-openjdk-demo-debug.x86_64 : OpenJDK Demos with full debug on
  java-1.8.0-openjdk-devel.i686 : OpenJDK Development Environment
  java-1.8.0-openjdk-devel.x86_64 : OpenJDK Development Environment
  java-1.8.0-openjdk-devel-debug.i686 : OpenJDK Development Environment with full
  java-1.8.0-openjdk-devel-debug.x86_64 : OpenJDK Development Environment with
  java-1.8.0-openjdk-headless.i686 : OpenJDK Runtime Environment
  java-1.8.0-openjdk-headless.x86_64 : OpenJDK Runtime Environment
  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 API Documentation
  java-1.8.0-openjdk-javadoc-debug.noarch : OpenJDK API Documentation for packages
  java-1.8.0-openjdk-javadoc-zip.noarch : OpenJDK API Documentation compressed in
  java-1.8.0-openjdk-javadoc-zip-debug.noarch : OpenJDK API Documentation
  java-1.8.0-openjdk-src.i686 : OpenJDK Source Bundle
  java-1.8.0-openjdk-src.x86_64 : OpenJDK Source Bundle
  java-1.8.0-openjdk-src-debug.i686 : OpenJDK Source Bundle for packages with
  java-1.8.0-openjdk-src-debug.x86_64 : OpenJDK Source Bundle for packages with
  java-11-openjdk.i686 : OpenJDK Runtime Environment 11
  java-11-openjdk.x86_64 : 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.i686 : OpenJDK Headless Runtime Environment 11
  java-11-openjdk-headless.x86_64 : 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 for packages with debug
  java-11-openjdk-src-debug.x86_64 : OpenJDK Source Bundle 11 for packages with
  ldapjdk.noarch : The Mozilla LDAP Java SDK

• 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/java
  lrwxrwxrwx 1 root root 22 Feb 13 10:40 /usr/bin/java -> /etc/alternatives/java
  [root@preproduct1 ~]# ls -lrt /etc/alternatives/java
  lrwxrwxrwx 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]# ll
  total 4
  lrwxrwxrwx 1 root root   26 Feb 13 10:44 java -> /etc/alternatives/java_sdk
  lrwxrwxrwx 1 root root   32 Feb 13 10:44 java-1.8.0 -> /etc/alternatives/java_sdk_1.8.0
  lrwxrwxrwx 1 root root   40 Feb 13 10:44 java-1.8.0-openjdk -> /etc/alternatives/java_sdk_1.8.0_openjdk
  drwxr-xr-x 7 root root 4096 Feb 13 10:44 java-1.8.0-openjdk-1.8.0.191.b12-1.el7_6.x86_64
  lrwxrwxrwx 1 root root   34 Feb 13 10:44 java-openjdk -> /etc/alternatives/java_sdk_openjdk
  lrwxrwxrwx 1 root root   21 Feb 13 10:40 jre -> /etc/alternatives/jre
  lrwxrwxrwx 1 root root   27 Feb 13 10:40 jre-1.8.0 -> /etc/alternatives/jre_1.8.0
  lrwxrwxrwx 1 root root   35 Feb 13 10:40 jre-1.8.0-openjdk -> /etc/alternatives/jre_1.8.0_openjdk
  lrwxrwxrwx 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/jre
  lrwxrwxrwx 1 root root   29 Feb 13 10:40 jre-openjdk -> /etc/alternatives/jre_openjdk

• 验证java是否安装成功

  • 查看java版本：java -version

    # java -version
    openjdk 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

• 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]# l
  total 20
  drwxr-xr-x 2 root root 4096 Feb 13 10:44 bin
  drwxr-xr-x 3 root root 4096 Feb 13 10:44 include
  drwxr-xr-x 4 root root 4096 Feb 13 10:40 jre
  drwxr-xr-x 3 root root 4096 Feb 13 10:44 lib
  drwxr-xr-x 2 root root 4096 Feb 13 10:44 tapset

  再次输入javac说明安装成功

  # 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 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

• 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