Centos7 卸载自带的OpenJDK

环境信息

CentOS Linux release 7.4.1708 (Core) 
jdk1.8.0_172

卸载OpenJDK

1. 在终端运行命令，查看是否有安装OpenJDK

   [vagrant@localhost ~]$ java -version
   openjdk 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)

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2. 如果已经存在了openjdk，查询需要卸载的内容

   [vagrant@localhost ~]$ rpm -qa | grep openjdk
   java-1.7.0-openjdk-headless-1.7.0.171-2.6.13.0.el7_4.x86_64
   java-1.8.0-openjdk-1.8.0.161-0.b14.el7_4.x86_64
   java-1.7.0-openjdk-1.7.0.171-2.6.13.0.el7_4.x86_64
   java-1.8.0-openjdk-headless-1.8.0.161-0.b14.el7_4.x86_64

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3. 根据第二步查询的要卸载的内容，使用命令rpm -e --nodeps进行卸载

[vagrant@localhost ~]$ sudo rpm -e --nodeps java-1.7.0-openjdk-headless-1.7.0.171-2.6.13.0.el7_4.x86_64
[vagrant@localhost ~]$ sudo rpm -e --nodeps java-1.8.0-openjdk-1.8.0.161-0.b14.el7_4.x86_64
[vagrant@localhost ~]$ sudo rpm -e --nodeps java-1.7.0-openjdk-1.7.0.171-2.6.13.0.el7_4.x86_64
[vagrant@localhost ~]$ sudo rpm -e --nodeps java-1.8.0-openjdk-headless-1.8.0.161-0.b14.el7_4.x86_64

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安装SunJDK

1. 在家目录下创建一个文件夹，并进入

   [vagrant@localhost ~]$ mkdir java
   [vagrant@localhost ~]$ cd java

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2. 下载SunJDK，得到文件jdk-8u172-linux-x64.tar.gz

   wget --no-check-certificate --no-cookies --header "Cookie: oraclelicense=accept-securebackup-cookie" http://download.oracle.com/otn-pub/java/jdk/8u172-b11/a58eab1ec242421181065cdc37240b08/jdk-8u172-linux-x64.tar.gz

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   [vagrant@localhost java]$ ls
   jdk-8u172-linux-x64.tar.gz

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3. 解压JDK

tar -zxvf jdk-8u172-linux-x64.tar.gz

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配置JDK环境变量

1. 在终端输入命令

   vim /etc/profile

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2. 在文本最后加上下面的内容

   
   #java environment  
   
   export JAVA_HOME=/home/vagrant/java/jdk1.8.0_172
   export CLASSPATH=.:${JAVA_HOME}/jre/lib/rt.jar:${JAVA_HOME}/lib/dt.jar:${JAVA_HOME}/lib/tools.jar  
   export PATH=$PATH:${JAVA_HOME}/bin

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3. 使配置生效

   source /etc/profile

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测试安装

1. 运行命令

[vagrant@localhost jdk1.8.0_172]$ java -version
java version "1.8.0_172"
Java(TM) SE Runtime Environment (build 1.8.0_172-b11)
Java HotSpot(TM) 64-Bit Server VM (build 25.172-b11, mixed mode)