Linux online installation JDK (version 1.8) graphic detailed version

Linux installs JDK online, command download

Online download JDK
command:wget --no-check-certificate --no-cookies --header "Cookie: oraclelicense=accept-securebackup-cookie" http://download.oracle.com/otn-pub/java/jdk/8u131-b11/d54c1d3a095b4ff2b6607d096fa80163/jdk-8u131-linux-x64.rpm
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Download reading bar: When the progress bar is 100%, the download is complete
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Check whether there is a JDK installation package in the current folder:
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Add execution permission:
First, let’s explain the meaning of the three letters rwx: r stands for readable and accessible; w stands for writable and modifiable; x stands for
　　executable Access and modify, but not execute
　　② Part 2 r – Belongs to the group to which the file belongs, means this user group can access, but cannot modify and execute
　　③ Part 3 r – Belongs to other users, means other users can only access this file or directory, but cannot be modified or executed.
　　④ Use - to indicate that there is no permission.
　　We need to add executable permissions to ourselves
. Command: chmod +x jdk-8u131-linux-x64.rpm
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Execute rpm to install
Command: rpm -ivh jdk-8u131-linux-x64.rpm

Check whether JDK is successfully installed at this time
Command:java -version

Check the installation path of JDK, (general default path: /usr/java/jdk1.8.0_131)
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Configure JDK environment variables
1. Edit environment variables

export JAVA_HOME=/usr/java/jdk1.8.0_131
export JRE_HOME=${
    
    JAVA_HOME}/jre
export CLASSPATH=.:${
    
    JAVA_HOME}/lib:${
    
    JRE_HOME}/lib:$CLASSPATH
export JAVA_PATH=${
    
    JAVA_HOME}/bin:${
    
    JRE_HOME}/bin
export PATH=$PATH:${
    
    JAVA_PATH}

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2. Edit the /etc/profile
command:vim /etc/profile
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3. Perform environment configuration
Command: i Enter edit mode
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Paste the edited above and
enter the command:wq!
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Force save and exit
to make the profile take effect immediately:source /etc/profile

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Check the JDK installation status
1. Use the javac command, there will be no command not found

2. Command:java -version
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3. Check whether the environment variable configuration you just set is correct
Command:echo $PATH
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yum install jdk
1. Check if JDK is installed, uninstall

yum list installed |grep java

java-1.8.0-openjdk.x86_64             1:1.8.0.121-0.b13.el7_3          @updates   
java-1.8.0-openjdk-headless.x86_64    1:1.8.0.121-0.b13.el7_3          @updates   
javapackages-tools.noarch             3.4.1-11.el7                     @base      
python-javapackages.noarch            3.4.1-11.el7                     @base      
tzdata-java.noarch                    2016j-1.el7                      @updates

2 Uninstall the CentOS system Java environment

[root@abc ~]# yum -y remove java-1.8.0-openjdk*        *表时卸载所有openjdk相关文件输入  
[root@abc ~]# yum -y remove tzdata-java.noarch         卸载tzdata-java

[root@192 ~]# yum -y remove java-1.8.0-openjdk* *表时卸载所有openjdk相关文件输入
[root@192 ~]# yum -y remove tzdata-java.noarch 卸载tzdata-java
3 list java environment installation packages

yum -y list java*   
或 [root@abc ~]#   yum search java | grep -i --color JDK                  查看JDK软件包列表

 yum  install  java-1.8.0-openjdk   java-1.8.0-openjdk-devel      
 安装JDK,如果没有java-1.8.0-openjdk-devel就没有javac命令

Linux online installation JDK (version 1.8) graphic detailed version

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