1.简介
在Oracle收购Sun后，Java的一系列产品就被整合到Oracle官网中，打开官网乍眼一看也不知道去哪里*载下**，还得一个一个的摸索尝试，而且网上大多数都是一些Oracle收购Sun前，或者就是一些老的资料文章，为了避免这些坑，宏哥才决定写着一篇文章。
JDK是 JAVA 的软件开发工具包，如果要使用JAVA来进行开发，或者部署基于其开发的应用，那么就需要安装JDK。本次将在Linux下安装JDK及配置环境。在以前宏哥也在Linux下安装过JDK，安装过程溜得飞起来。结果这次安装过程中却是十分的不顺，所以才有了这篇文章用来记录和分享安装 过程中遇到的问题和心得体会，希望对各位有所帮忙，避免做更多的无用功。
宏哥的环境：
查看Linux环境输入命令： lsb_release -a
[admin@oftpclient201 ~]$ lsb_release -a
LSB Version: :core- 4.1 -amd64:core- 4.1 -noarch:cxx- 4.1 -amd64:cxx- 4.1 -noarch:desktop- 4.1 -amd64:desktop- 4.1 -noarch:languages- 4.1 -amd64:languages- 4.1 -noarch:printing- 4.1 -amd64:printing- 4.1 -noarch
Distributor ID: CentOS
Description: CentOS Linux release 7.9 . 2009 (Core)
Release: 7.9 . 2009
2.*载下**JDK
在安装之前，检查是否存在Linux下自带的OpenJDK，命令： rpm -qa | grep java 。若存在，则需要进行卸载，命令： rpm -e --nodeps 卸载的软件名 。
其他方法：
java -version
echo $PATH 看环境变量bai是否配du置了java路径
find / -name java 查找zhijava文件
JDK历史版本链接：https://www.oracle.com/technetwork/java/javase/archive-139210.html
接着，我们可以通过 wget 命令*载下**JDK安装包，或者*载下**后传到Linux。我这里*载下**的安装包版本是 jdk-8u281-linux-x64.tar.gz 。
2.1使用wget*载下**JDK8
每次去官网*载下**JDK有点烦 但是直接使用wget 又得同意协议所以 使用如下的wget就好了(注意是64位的哦)
1.先去官网看一下地址变化 没有如下 :修改后面的*载下**地址即可 注意哦~现在和以前变化挺大的，所以宏哥在这里赘述一下具体步骤：
（1）在浏览器的地址栏输入JDK官网 ， 如下图所示：
（2）鼠标放在product上在下拉菜单中点击Java，如下图所示：
（3）然后再点击“Download Java”，如下图所示：
（4）下滑页面找到Java SE8，然后点击“JDK Download”,如下图所示：
（5）找到Linux系统的64位的JDK，选中安装包右键，点击“复制链接地址”，如下图所示：
（6）在xshell上输入命令wget --no-check-certificate --no-cookies --header "Cookie: oraclelicense=accept-securebackup-cookie"后面加上你刚才复制的*载下**链接
2.然后使用下面的wget*载下**就好了~(注意文件的后缀，有时候不可以直接解压需要重命名后缀名哦)
wget --no-check-certificate --no-cookies --header "Cookie: oraclelicense=accept-securebackup-cookie" http://download.oracle.com/otn-pub/java/jdk/8u171-b11/512cd62ec5174c3487ac17c61aaa89e8/jdk-8u171-linux-x64.tar.gz
3.解压安装包
创建一个文件夹，用于存放JDK安装包，然后解压到该目录下。
创建文件夹： mkdir /usr/JDK 进入文件夹： cd /usr/JDK 将*载下**好的压缩文件剪贴到创建好的文件夹下： mv jdk-8u281-linux-x64.tar.gz /usr/JDK/ 解压： tar -zxvf jdk-8u281-linux-x64.tar.gz
可以看到，本次解压到了当前目录 /usr/JDK/jdk1.8.0_281 下。
4.配置环境
解压完成之后，我们要配置下环境变量，通过 vim 命令修改配置文件 /etc/profile 来设置环境变量。
vim /etc/profile
在文件最后一行，输入 i 进入编辑模式，添加以下内容，然后按 Esc 退出编辑模式，再输入 :wq 保存并退出。
export JAVA_HOME=/usr/JDK/jdk1. 8 .0_281
export JRE_HOME=${JAVA_HOME}/jre
export CLASSPATH=.:${JAVA_HOME}/lib:${JRE_HOME}/lib
export PATH=${JAVA_HOME}/bin:$PATH
设置完之后，如果要使环境变量立即生效，需要通过命令： source /etc/profile ，重新加载配置文件。
5.验证是否安装成功
所有都配置好了，我们需要验证下是否安装成功。
依次输入 java -version 、 java 、 javac ，不会出现报错并且显示出 jdk版本号及 java/javac相关命令参数说明界面。
[admin@oftpclient201 ~]$ java -version
java version "1.8.0_281"
Java(TM) SE Runtime Environment (build 1.8 .0_281-b09)
Java HotSpot(TM) 64 -Bit Server VM (build 25.281 -b09, mixed mode)
[admin@oftpclient201 ~]$ java
Usage: java [-options] class [args...]
(to execute a class )
or java [-options] -jar jarfile [args...]
(to execute a jar file) where options include:
-d32 use a 32 -bit data model if available
-d64 use a 64 -bit data model if available
-server to select the "server" VM
The default VM is server.
-cp < class search path of directories and zip/jar files>
-classpath < class search path of directories and zip/jar files>
A : separated list of directories, JAR archives,
and ZIP archives to search for class files.
-D<name>=<value>
set a system property
-verbose:[ class |gc|jni]
enable verbose output
-version print product version and exit
-version:<value>
Warning: this feature is deprecated and will be removed
in a future release.
require the specified version to run
-showversion print product version and continue
-jre-restrict-search | -no-jre-restrict-search
Warning: this feature is deprecated and will be removed
in a future release.
include/exclude user private JREs in the version search
-? -help print this help message
-X print help on non-standard options
-ea[:<packagename>...|:<classname>]
-enableassertions[:<packagename>...|:<classname>]
enable assertions with specified granularity
-da[:<packagename>...|:<classname>]
-disableassertions[:<packagename>...|:<classname>]
disable assertions with specified granularity
-esa | -enablesystemassertions
enable system assertions
-dsa | -disablesystemassertions
disable system assertions
-agentlib:<libname>[=<options>]
load native agent library <libname>, e.g. -agentlib:hprof
see also, -agentlib:jdwp=help and -agentlib:hprof=help
-agentpath:<pathname>[=<options>]
load native agent library by full pathname
-javaagent:<jarpath>[=<options>]
load Java programming language agent, see java.lang.instrument
-splash:<imagepath>
show splash screen with specified image
See http: //www.oracle.com/technetwork/java/javase/documentation/index.html for more details.
[admin@oftpclient201 ~]$ 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
[admin@oftpclient201 ~]$
6.小结
安装过程中宏哥为了避免麻烦不是在Windows上直接安装好然后再上传到Linux上，而是直接用weget命令直接安装的，结果遇到如下一系列的问题：（1）wget+复制好的*载下**地址
[admin@oftpclient201 ~]$ wget https: //download.oracle.com/otn/java/jdk/8u281-b09/89d678f2be164786b292527658ca1605/jdk-8u281-linux-x64.tar.gz--2026-03-17T04:12:44+00:00-- https://download.oracle.com/otn/java/jdk/8u281-b09/89d678f2be164786b292527658ca1605/jdk-8u281-linux-x64.tar.gzResolving download.oracle.com (download.oracle.com)... 184.50.93.194Connecting to download.oracle.com (download.oracle.com)|184.50.93.194|:443... connected.
HTTP request sent, awaiting response... 302 Moved Temporarily
Location: https: //edelivery.oracle.com/akam/otn/java/jdk/8u281-b09/89d678f2be164786b292527658ca1605/jdk-8u281-linux-x64.tar.gz [following]
-- 2021 - 02 - 25 15 : 25 : 48 -- https: //edelivery.oracle.com/akam/otn/java/jdk/8u281-b09/89d678f2be164786b292527658ca1605/jdk-8u281-linux-x64.tar.gz
Resolving edelivery.oracle.com (edelivery.oracle.com)... 184.30 . 17.110 , 2600 : 1400 :c000: 482 :: 366 , 2600 : 1400 :c000: 488 :: 366
Connecting to edelivery.oracle.com (edelivery.oracle.com)| 184.30 . 17.110 |: 443 ... connected.
HTTP request sent, awaiting response... 302 Moved Temporarily
Location: https: //login.oracle.com:443/oam/server/obrareq.cgi?encquery%3D4PIlzUXFrmsJOQa3pTVPbD8FleZqJX%2Bqm5A%2BmXnkil9RBAqGW%2Bd5Z3FgcL03OH1P%2FL%2FPpBosJhXNi%2BaNvJ5gWRCWlkmsTghONwL1Ixk8tJ66nMfQItxzYLYEA6Ae%2F4xxJtk3wvyzw4EzT%2B88B%2BHNgKJs6w67VGaR6kHqcVem1SIW%2Fxxps6xSH%2Bqe9li%2BI0FMXUw2Dptss7A0VEtYvTTpUHnLteqH9Wt2TJiK%2F8%2BVmtRUTs5Y2YaOxZqrr6VcBsyAi83RSY1PKFiJChmpxiao1%2Bomcz9PKzc04xMlEg2hVJFAoTxUkyPKCWWEmipcbGPfcQOJYVrfjGqqmAGIDBfUfmpAGcQf21ceJqkm739Jf%2Bue68iM7YPcI7WOdFjxWLG9Ykj2NVjTwjmCDzZUsBFzMiT8SeXRqH7dTevRYZuzg0b%2F8PZNqeTjzZ5LHzG6WA1%2FlWsXpwgBuB3OklWgZs5HBg25Mx5Uqdu%2BHzc6qzaGNlWKrQj5pWUvGpz1rVPB23SywqnzFy9iUm4I%2FlXYeJDzJQ%3D%3D%20agentid%3Dedelivery-extprod%20ver%3D1%20crmethod%3D2&ECID-Context=1.005j2GF_XvzFo2KimTctkJ00023d00wI1l%3BkXjE [following]
-- 2021 - 02 - 25 15 : 25 : 50 -- https: //login.oracle.com/oam/server/obrareq.cgi?encquery%3D4PIlzUXFrmsJOQa3pTVPbD8FleZqJX%2Bqm5A%2BmXnkil9RBAqGW%2Bd5Z3FgcL03OH1P%2FL%2FPpBosJhXNi%2BaNvJ5gWRCWlkmsTghONwL1Ixk8tJ66nMfQItxzYLYEA6Ae%2F4xxJtk3wvyzw4EzT%2B88B%2BHNgKJs6w67VGaR6kHqcVem1SIW%2Fxxps6xSH%2Bqe9li%2BI0FMXUw2Dptss7A0VEtYvTTpUHnLteqH9Wt2TJiK%2F8%2BVmtRUTs5Y2YaOxZqrr6VcBsyAi83RSY1PKFiJChmpxiao1%2Bomcz9PKzc04xMlEg2hVJFAoTxUkyPKCWWEmipcbGPfcQOJYVrfjGqqmAGIDBfUfmpAGcQf21ceJqkm739Jf%2Bue68iM7YPcI7WOdFjxWLG9Ykj2NVjTwjmCDzZUsBFzMiT8SeXRqH7dTevRYZuzg0b%2F8PZNqeTjzZ5LHzG6WA1%2FlWsXpwgBuB3OklWgZs5HBg25Mx5Uqdu%2BHzc6qzaGNlWKrQj5pWUvGpz1rVPB23SywqnzFy9iUm4I%2FlXYeJDzJQ%3D%3D%20agentid%3Dedelivery-extprod%20ver%3D1%20crmethod%3D2&ECID-Context=1.005j2GF_XvzFo2KimTctkJ00023d00wI1l%3BkXjE
Resolving login.oracle.com (login.oracle.com)... 209.17 . 4.8
Connecting to login.oracle.com (login.oracle.com)| 209.17 . 4.8 |: 443 ... connected.
HTTP request sent, awaiting response... 200 OK
Length: 4103 ( 4 .0K) [text/html]
Saving to: ‘jdk-8u281-linux-x64.tar.gz. 1 ’
100 %[==============================================================================================================================================================================>] 4 , 103 17 .6KB/s in 0 .2s
2021 - 02 - 25 15 : 25 : 51 ( 17.6 KB/s) - ‘jdk-8u281-linux-x64.tar.gz. 1 ’ saved [ 4103 / 4103 ]
[admin@oftpclient201 ~]$
从上图看着好像是*载下**成功了，但是宏哥在解压的时候有报错了，报错如下：
[admin@oftpclient201 ~]$ tar -zxvf jdk-8u281-linux-x64.tar.gz
gzip: stdin: not in gzip format
tar: Child returned status 1
tar: Error is not recoverable: exiting now
[admin@oftpclient201 ~]$
从上图的报错可以发现说是压缩包不完整，宏哥好奇既然*载下**成功怎么会是不完整的了，于是宏哥看了一下压缩包的大小，如下所示才4.1K，
[admin@oftpclient201 ~]$ ll -lh
total 16K-rw-rw-r--. 1 admin admin 0 Feb 25 15 : 25 ]-rw-rw-r--. 1 admin admin 4 .1K Feb 25 15 : 24 jdk-8u281-linux-x64.tar.gz-rw-rw-r--. 1 admin admin 39 Feb 2 16 : 20 test.txt-rw-rw-r--. 1 admin admin 78 Feb 2 16 : 21 t.zip
[admin@oftpclient201 ~]$
这个与Oracle官网显示的大小100多M差太多了，所以确定是*载下**不成功而且回过头来看一下*载下**时间几乎零点几秒就*载下**完成了，更加确定*载下**的压缩包是不完整的。
查了资料说是由于Oracle需要accept license、cookie，所以需要给wget带如下参数即可，于是就有了第二种方法的尝试（2）wget --no-check-certificate --no-cookies --header "Cookie: oraclelicense=accept-securebackup-cookie"+复制好的*载下**地址
[admin@oftpclient201 ~]$ wget --no-cookies --header "Cookie: oraclelicense=accept-securebackup-cookie;" https: //download.oracle.com/otn/java/jdk/8u281-b09/89d678f2be164786b292527658ca1605/jdk-8u281-linux-x64.tar.gz
-- 2021 - 02 - 25 15 : 56 : 55 -- https: //download.oracle.com/otn/java/jdk/8u281-b09/89d678f2be164786b292527658ca1605/jdk-8u281-linux-x64.tar.gz
Resolving download.oracle.com (download.oracle.com)... 92.123 . 228.99
Connecting to download.oracle.com (download.oracle.com)| 92.123 . 228.99 |: 443 ... connected.
HTTP request sent, awaiting response... 302 Moved Temporarily
Location: https: //edelivery.oracle.com/akam/otn/java/jdk/8u281-b09/89d678f2be164786b292527658ca1605/jdk-8u281-linux-x64.tar.gz [following]
-- 2021 - 02 - 25 15 : 56 : 56 -- https: //edelivery.oracle.com/akam/otn/java/jdk/8u281-b09/89d678f2be164786b292527658ca1605/jdk-8u281-linux-x64.tar.gz
Resolving edelivery.oracle.com (edelivery.oracle.com)... 23.76 . 64.181 , 2a02:26f0:a00:3be:: 366 , 2a02:26f0:a00: 385 :: 366
Connecting to edelivery.oracle.com (edelivery.oracle.com)| 23.76 . 64.181 |: 443 ... connected.
HTTP request sent, awaiting response... 302 Moved Temporarily
Location: https: //login.oracle.com:443/oam/server/obrareq.cgi?encquery%3DSyDVndLEpx6WpSyvf2If6hV7vdEN%2BIvCiOpWhz5xUgWJKCBA4mYVvksWHq4vohW6kyMvXAjWfJyda2XrAkGPdxyVK9FcqsRYhvs1DZDEbVLAtEnG5a2Zw2R07iGjm1v79FPjjXyDKSR%2B52%2F0qdEhmP6pPdLPEjhEHVNXr1usKyMmhI0FeYrjn7YcQLjvVOGbZsVR6%2Bu0hqU8jZPxDtXpo8zANJoPdEGxwOiThOVkCWm2cvpOC3Y0QBICZ1yvcWtvTOSHUwZMZgeEp2EdCqlHwH0nm0JWFAKHf6qL9RI1Qs0ZRNth%2FkzjYDLrlY%2B9D1%2BESsQHCAUa2kRHwKXf89u%2BbIUMT2o0xqFtzvJLgQjlG9pUZ7JIxHYVZXzRc1lQwiJove8sjHWNOaujjaryNEGMH5WfiqCp8Y6ogcgd%2B4qNoBLOz7oCOsZkYrzAyfq7481ei7PPvESoBRw6ezsmB06LZt1YHnpf%2BGwf2q33TckhLOVb8C6Bs3bwkmhBfwhDNMnGd%2BonHh%2Fg7kcNscjuTkbwFw%3D%3D%20agentid%3Dedelivery-extprod%20ver%3D1%20crmethod%3D2&ECID-Context=1.005j2HyusRcFo2KimTXvWJ0002ZZ00IcIc%3BkXjE [following]
-- 2021 - 02 - 25 15 : 56 : 57 -- https: //login.oracle.com/oam/server/obrareq.cgi?encquery%3DSyDVndLEpx6WpSyvf2If6hV7vdEN%2BIvCiOpWhz5xUgWJKCBA4mYVvksWHq4vohW6kyMvXAjWfJyda2XrAkGPdxyVK9FcqsRYhvs1DZDEbVLAtEnG5a2Zw2R07iGjm1v79FPjjXyDKSR%2B52%2F0qdEhmP6pPdLPEjhEHVNXr1usKyMmhI0FeYrjn7YcQLjvVOGbZsVR6%2Bu0hqU8jZPxDtXpo8zANJoPdEGxwOiThOVkCWm2cvpOC3Y0QBICZ1yvcWtvTOSHUwZMZgeEp2EdCqlHwH0nm0JWFAKHf6qL9RI1Qs0ZRNth%2FkzjYDLrlY%2B9D1%2BESsQHCAUa2kRHwKXf89u%2BbIUMT2o0xqFtzvJLgQjlG9pUZ7JIxHYVZXzRc1lQwiJove8sjHWNOaujjaryNEGMH5WfiqCp8Y6ogcgd%2B4qNoBLOz7oCOsZkYrzAyfq7481ei7PPvESoBRw6ezsmB06LZt1YHnpf%2BGwf2q33TckhLOVb8C6Bs3bwkmhBfwhDNMnGd%2BonHh%2Fg7kcNscjuTkbwFw%3D%3D%20agentid%3Dedelivery-extprod%20ver%3D1%20crmethod%3D2&ECID-Context=1.005j2HyusRcFo2KimTXvWJ0002ZZ00IcIc%3BkXjE
Resolving login.oracle.com (login.oracle.com)... 209.17 . 4.8
Connecting to login.oracle.com (login.oracle.com)| 209.17 . 4.8 |: 443 ... connected.
HTTP request sent, awaiting response... 200 OK
Length: 4149 ( 4 .1K) [text/html]
Saving to: ‘jdk-8u281-linux-x64.tar.gz’
100 %[==============================================================================================================================================================================>] 4 , 149 --.-K/s in 0s
2021 - 02 - 25 15 : 56 : 59 ( 24.7 MB/s) - ‘jdk-8u281-linux-x64.tar.gz’ saved [ 4149 / 4149 ]
[admin@oftpclient201 ~]$
按方法一确认以后发现*载下**的压缩包还是不完整，查了资料说是按这种方法就可以，也有的说是这种方法已经过时了。还有的说是wget命令有缺陷不会重定向，但是抓包是发现网页中点击*载下**会有重定向的请求，...等等各种各样的说法，第二天宏哥正要老老实实的在Oracle注册、登录账号（太麻烦）据说注册、登录账号后，复制的*载下**链接中会自带cookie、协议和安全认证，然后用wget命令+上此*载下**链接可以*载下**成功，但是宏哥觉得有点麻烦，这种方法就没尝试，你如果有兴趣的话，童鞋们或者小伙伴自己可以尝试一下按宏哥说的是否可以成功*载下**压缩包。，然后*载下**Linux的JDK安装包，然后再上传到Linux系统中。但是宏哥这个人比较懒吧，也比较不甘心，所以再次决定再查查资料。结果百度查询了半天左右，经过反复的摸索终于找到一个靠谱的答案。网上那些太多的都是复制来复制去，都不能解决实质性问题。（3）在方法二的基础上将*载下**地址中的otn修改成otn-pub
[admin@oftpclient201 ~]$ wget --no-check-certificate --no-cookies --header "Cookie: oraclelicense=accept-securebackup-cookie" https: //download.oracle.com/otn-pub/java/jdk/8u281-b09/89d678f2be164786b292527658ca1605/jdk-8u281-linux-x64.tar.gz
-- 2021 - 02 - 25 16 : 10 : 40 -- https: //download.oracle.com/otn-pub/java/jdk/8u281-b09/89d678f2be164786b292527658ca1605/jdk-8u281-linux-x64.tar.gz
Resolving download.oracle.com (download.oracle.com)... 184.86 . 92.87
Connecting to download.oracle.com (download.oracle.com)| 184.86 . 92.87 |: 443 ... connected.
HTTP request sent, awaiting response... 302 Moved Temporarily
Location: https: //edelivery.oracle.com/otn-pub/java/jdk/8u281-b09/89d678f2be164786b292527658ca1605/jdk-8u281-linux-x64.tar.gz [following]
-- 2021 - 02 - 25 16 : 10 : 41 -- https: //edelivery.oracle.com/otn-pub/java/jdk/8u281-b09/89d678f2be164786b292527658ca1605/jdk-8u281-linux-x64.tar.gz
Resolving edelivery.oracle.com (edelivery.oracle.com)... 23.76 . 87.214 , 2600 : 1400 :c000: 482 :: 366 , 2600 : 1400 :c000: 488 :: 366
Connecting to edelivery.oracle.com (edelivery.oracle.com)| 23.76 . 87.214 |: 443 ... connected.
HTTP request sent, awaiting response... 302 Moved Temporarily
Location: https: //download.oracle.com/otn-pub/java/jdk/8u281-b09/89d678f2be164786b292527658ca1605/jdk-8u281-linux-x64.tar.gz?AuthParam=1614240762_cf401250c965e2946ab43486aa6c2db3 [following]
-- 2021 - 02 - 25 16 : 10 : 42 -- https: //download.oracle.com/otn-pub/java/jdk/8u281-b09/89d678f2be164786b292527658ca1605/jdk-8u281-linux-x64.tar.gz?AuthParam=1614240762_cf401250c965e2946ab43486aa6c2db3
Connecting to download.oracle.com (download.oracle.com)| 184.86 . 92.87 |: 443 ... connected.
HTTP request sent, awaiting response... 200 OK
Length: 143722924 (137M) [application/x-gzip]
Saving to: ‘jdk-8u281-linux-x64.tar.gz’
100 %[==============================================================================================================================================================================>] 143 , 722 , 924 2 .67MB/s in 57s
2021 - 02 - 25 16 : 11 : 40 ( 2.41 MB/s) - ‘jdk-8u281-linux-x64.tar.gz’ saved [ 143722924 / 143722924 ]
[admin@oftpclient201 ~]$ ll -h
从上图可以看出*载下**时间是57s,虽然这个时间与网速有关系，但是大致感觉时间也差不多了。因此宏哥判断这次是真的解决了，安装包*载下**成功了。和宏哥来再次看一下压缩的安装包的大小是138M，和官网展示的大小也差不多，预示着*载下**成功，问题解决
[admin@oftpclient201 ~]$ ll -h
total 138M-rw-rw-r--. 1 admin admin 0 Feb 25 16 : 09 ]-rw-rw-r--. 1 admin admin 138M Dec 11 03 : 12 jdk-8u281-linux-x64.tar.gz-rw-rw-r--. 1 admin admin 39 Feb 2 16 : 20 test.txt-rw-rw-r--. 1 admin admin 78 Feb 2 16 : 21 t.zip
[admin@oftpclient201 ~]$
7.拓展
7.1linux下如何查看已安装的centos版本信息
1.Linux查看当前操作系统版本信息 cat /proc/version
[admin@oftpclient201 ~]$ cat /proc/version
Linux version 3.10 . 0 - 1160.11 . 1 .el7.x86_64 (mockbuild@kbuilder.bsys.centos.org) (gcc version 4.8 . 5 20150623 (Red Hat 4.8 . 5 - 44 ) (GCC) ) # 1 SMP Fri Dec 18 16 : 34 : 56 UTC 2020
[admin@oftpclient201 ~]$
2.Linux查看版本当前操作系统内核信息 uname -a
[admin@oftpclient201 ~]$ uname -a
Linux oftpclient201.test.cedex.cn 3.10 . 0 - 1160.11 . 1 .el7.x86_64 # 1 SMP Fri Dec 18 16 : 34 : 56 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
3.linux查看版本当前操作系统发行信息 cat /etc/issue 或 cat /etc/centos-release
[admin@oftpclient201 ~]$ cat /etc/centos-release
CentOS Linux release 7.9 . 2009 (Core)
4.Linux查看cpu相关信息，包括型号、主频、内核信息等 cat /etc/cpuinfo
[admin@oftpclient201 ~]$ cat /proc/cpuinfo
processor : 0 #数值为0表示第1颗cpu
vendor_id : GenuineIntel
cpu family : 6
model : 58
model name : Intel(R) Core(TM) i5-3320M CPU @ 2 .60GHz
stepping : 9
microcode : 0x15
cpu MHz : 2594.170
cache size : 3072 KB
physical id : 0
siblings : 1
core id : 0
cpu cores : 1
apicid : 0
initial apicid : 0
fpu : yes
fpu_exception : yes
cpuid level : 13
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts mmx fxsr sse sse2 ss syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts nopl xtopology tsc_reliable nonstop_tsc aperfmperf eagerfpu pni pclmulqdq ssse3 cx16 pcid sse4_1 sse4_2 x2apic popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm epb fsgsbase tsc_adjust smep dtherm ida arat pln pts
bogomips : 5188.34
clflush size : 64
cache_alignment : 64
address sizes : 42 bits physical, 48 bits virtual
power management:
processor : 1 #数值为1表示第2颗cpu
vendor_id : GenuineIntel
cpu family : 6
model : 58
model name : Intel(R) Core(TM) i5-3320M CPU @ 2 .60GHz
stepping : 9
microcode : 0x15
cpu MHz : 2594.170
cache size : 3072 KB
physical id : 2
siblings : 1
core id : 0
cpu cores : 1
apicid : 2
initial apicid : 2
fpu : yes
fpu_exception : yes
cpuid level : 13
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts mmx fxsr sse sse2 ss syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts nopl xtopology tsc_reliable nonstop_tsc aperfmperf eagerfpu pni pclmulqdq ssse3 cx16 pcid sse4_1 sse4_2 x2apic popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm epb fsgsbase tsc_adjust smep dtherm ida arat pln pts
bogomips : 5188.34
clflush size : 64
cache_alignment : 64
address sizes : 42 bits physical, 48 bits virtual
power management:
processor ： 系统中逻辑处理核的编号。对于单核处理器，则课认为是其CPU编号，对于多核处理器则可以是物理核、或者使用超线程技术虚拟的逻辑核 vendor_id ： CPU制造商 cpu family ： CPU产品系列代号 model ： CPU属于其系列中的哪一代的代号 model name： CPU属于的名字及其编号、标称主频 stepping ： CPU属于制作更新版本 cpu MHz ： CPU的实际使用主频 cache size ： CPU二级缓存大小 physical id ： 单个CPU的标号 siblings ： 单个CPU逻辑物理核数 core id ： 当前物理核在其所处CPU中的编号，这个编号不一定连续 cpu cores ： 该逻辑核所处CPU的物理核数 apicid ： 用来区分不同逻辑核的编号，系统中每个逻辑核的此编号必然不同，此编号不一定连续 fpu ： 是否具有浮点运算单元（Floating Point Unit） fpu_exception ： 是否支持浮点计算异常 cpuid level ： 执行cpuid指令前，eax寄存器中的值，根据不同的值cpuid指令会返回不同的内容 wp ： 表明当前CPU是否在内核态支持对用户空间的写保护（Write Protection） flags ： 当前CPU支持的功能 bogomips ： 在系统内核启动时粗略测算的CPU速度（Million Instructions Per Second） clflush size ： 每次刷新缓存的*小单大**位 cache_alignment ： 缓存地址对齐单位 address sizes ： 可访问地址空间位数
5.Linux查看版本说明当前CPU运行在32bit模式下(但不代表CPU不支持64bit)
[admin@oftpclient201 etc]$ getconf LONG_BIT 64
7.2uname的使用
uname命令用于打印当前系统相关信息（内核版本号、硬件架构、主机名称和操作系统类型等）。
uname -a显示全部信息-m或--machine：显示电脑类型；-r或--release：显示操作系统的发行编号；-s或--sysname：显示操作系统名称；-v：显示操作系统的版本；-p或--processor：输出处理器类型或 "unknown" ；-i或--hardware-platform：输出硬件平台或 "unknown" ；-o或--operating-system：输出操作系统名称；--help：显示帮助；--version：显示版本信息。
7.3查看Linux版本
1.查看系统版本信息的命令 lsb_release -a(使用命令时提示command not found,需要安装yum install redhat-lsb -y)
[admin@oftpclient201 etc]$
[admin@oftpclient201 etc]$ lsb_release -a
LSB Version: :core- 4.1 -amd64:core- 4.1 -noarch:cxx- 4.1 -amd64:cxx- 4.1 -noarch:desktop- 4.1 -amd64:desktop- 4.1 -noarch:languages- 4.1 -amd64:languages- 4.1 -noarch:printing- 4.1 -amd64:printing- 4.1 -noarch
Distributor ID: CentOS
Description: CentOS Linux release 7.9 . 2009 (Core)
Release: 7.9 . 2009
Codename: Core
注:这个命令适用于所有的linux，包括RedHat、SUSE、Debian等发行版。2.查看centos版本号 cat /etc/issue
[admin@oftpclient201 etc]$ cat /etc/issue
\S
Kernel \r on an \m
[admin@oftpclient201 etc]$
3.使用 file /bin/ls
[admin@oftpclient201 etc]$ file /bin/ls/bin/ls: ELF 64 -bit LSB executable, x86- 64 , version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6 . 32 , BuildID[sha1]=c8ada1f7095f6b2bb7ddc848e088c2d615c3743e, stripped
[admin@oftpclient201 etc]$
原文链接：Linux下安装JDK 1.8你必须知道的那些糟心事！
请关注+私信回复：“测试”就可以免费拿到软件测试学习资料，同时进入群学习交流~~
