JDK
JDK和JRE
JRE：它是Java Runtime Environment缩写，指Java运行时环境， 包含 JVM + Java核心类库
JDK：它是Java Development Kit，即 Java 语言的软件开发工具包。
JDK也就是常说的J2SE，在1999年，正式发布了Java第二代平台，发布了三个版本：
J2SE：标准版，适用于桌面平台
J2EE：企业版，java在企业级开发所有规范的总和，共有13个大的规范
J2ME：微型版，适用于移动、无线、机顶盒等设备环境
2005年，Java的版本又更名为JavaSE、JavaEE、JavaME
Servlet、Jsp都包含在JavaEE规范中
JDK7、JDK8、JDK11是LTS（Long Term Suppot）
| 版本 | 项目名称 | 发行日期 |
|---|---|---|
| JDK 1.1.4 | Sparkler（宝石） | 1997-09-12 |
| JDK 1.1.5 | Pumpkin（南瓜） | 1997-12-13 |
| JDK 1.1.6 | Abigail（阿比盖尔–女子名） | 1998-04-24 |
| JDK 1.1.7 | Brutus（布鲁图–古罗马政治家和将军） | 1998-09-28 |
| JDK 1.1.8 | Chelsea（切尔西–城市名） | 1999-04-08 |
| J2SE 1.2 | Playground（运动场） | 1998-12-04 |
| J2SE 1.2.1 | none（无） | 1999-03-30 |
| J2SE 1.2.2 | Cricket（蟋蟀） | 1999-07-08 |
| J2SE 1.3 | Kestrel（美洲红隼） | 2000-05-08 |
| J2SE 1.3.1 | Ladybird（瓢虫） | 2001-05-17 |
| J2SE 1.4.0 | Merlin（灰背隼） | 2002-02-13 |
| J2SE 1.4.1 | grasshopper（蚱蜢） | 2002-09-16 |
| J2SE 1.4.2 | Mantis（螳螂） | 2003-06-26 |
| Java SE 5.0 (1.5.0) | Tiger（老虎） | 2004-09-30 |
| Java SE 6.0 (1.6.0) | Mustang（野马） | 2006-04 |
| Java SE 7.0 (1.7.0) | Dolphin（海豚） | 2011-07-28 |
| Java SE 8.0 (1.8.0) | Spider（蜘蛛） | 2014-03-18 |
| Java SE 9 | 2017-09-21 | |
| Java SE 10 | 2018-03-14 [3] |
JDK协议基于 JRL(JavaResearch License)协议
OpenJDK
OpenJDK是Sun公司采用GPL v2协议发布的JDK开源版本，于2009年正式发布。
官方网站：https://openjdk.java.net/projects/jdk6/
OpenJDK 7是基于JDK7的beta版开发，但为了也将Java SE 6开源，从OpenJDK7的b20构建反向分支开发，从中剥离了不符合Java SE 6规范的代码，发布OpenJDK 6。所以OpenJDK6和JDK6没什么关系。
OpenJDK使用GPL v2可以用于商业用途。
安装 openjdk
- 在Centos中，可以使用 yum 仓库安装 openjdk
[root@centos8 ~]#dnf list "*jdk*"
BaseOS 218 kB/s | 3.9 kB 00:00
AppStream 207 kB/s | 4.3 kB 00:00
EPEL 27 kB/s | 5.3 kB 00:00
EPEL 6.9 MB/s | 5.6 MB 00:00
extras 6.8 kB/s | 1.5 kB 00:00
Available Packages
copy-jdk-configs.noarch 3.7-1.el8 AppStream
java-1.8.0-openjdk.x86_64 1:1.8.0.232.b09-0.el8_0 AppStream
java-1.8.0-openjdk-accessibility.x86_64 1:1.8.0.232.b09-0.el8_0 AppStream
java-1.8.0-openjdk-demo.x86_64 1:1.8.0.232.b09-0.el8_0 AppStream
java-1.8.0-openjdk-devel.x86_64 1:1.8.0.232.b09-0.el8_0 AppStream
java-1.8.0-openjdk-headless.x86_64 1:1.8.0.232.b09-0.el8_0 AppStream
java-1.8.0-openjdk-javadoc.noarch 1:1.8.0.232.b09-0.el8_0 AppStream
java-1.8.0-openjdk-javadoc-zip.noarch 1:1.8.0.232.b09-0.el8_0 AppStream
java-1.8.0-openjdk-src.x86_64 1:1.8.0.232.b09-0.el8_0 AppStream
java-11-openjdk.x86_64 1:11.0.5.10-0.el8_0 AppStream
java-11-openjdk-demo.x86_64 1:11.0.5.10-0.el8_0 AppStream
java-11-openjdk-devel.x86_64 1:11.0.5.10-0.el8_0 AppStream
java-11-openjdk-headless.x86_64 1:11.0.5.10-0.el8_0 AppStream
java-11-openjdk-javadoc.x86_64 1:11.0.5.10-0.el8_0 AppStream
java-11-openjdk-javadoc-zip.x86_64 1:11.0.5.10-0.el8_0 AppStream
java-11-openjdk-jmods.x86_64 1:11.0.5.10-0.el8_0 AppStream
java-11-openjdk-src.x86_64 1:11.0.5.10-0.el8_0 AppStream
java-latest-openjdk.x86_64 1:13.0.2.8-1.rolling.el8 epel
java-latest-openjdk-demo.x86_64 1:13.0.2.8-1.rolling.el8 epel
java-latest-openjdk-demo-slowdebug.x86_64 1:13.0.2.8-1.rolling.el8 epel
java-latest-openjdk-devel.x86_64 1:13.0.2.8-1.rolling.el8 epel
java-latest-openjdk-devel-slowdebug.x86_64 1:13.0.2.8-1.rolling.el8 epel
java-latest-openjdk-headless.x86_64 1:13.0.2.8-1.rolling.el8 epel
java-latest-openjdk-headless-slowdebug.x86_64 1:13.0.2.8-1.rolling.el8 epel
java-latest-openjdk-javadoc.x86_64 1:13.0.2.8-1.rolling.el8 epel
java-latest-openjdk-javadoc-zip.x86_64 1:13.0.2.8-1.rolling.el8 epel
java-latest-openjdk-jmods.x86_64 1:13.0.2.8-1.rolling.el8 epel
java-latest-openjdk-jmods-slowdebug.x86_64 1:13.0.2.8-1.rolling.el8 epel
java-latest-openjdk-slowdebug.x86_64 1:13.0.2.8-1.rolling.el8 epel
java-latest-openjdk-src.x86_64 1:13.0.2.8-1.rolling.el8 epel
java-latest-openjdk-src-slowdebug.x86_64 1:13.0.2.8-1.rolling.el8 epel
[root@centos8 ~]#dnf -y install java-1.8.0-openjdk.x86_64
[root@centos8 ~]#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)
# java -version
openjdk version "1.8.0_212"
OpenJDK Runtime Environment (build 1.8.0_212-b04)
OpenJDK 64-Bit Server VM (build 25.212-b04, mixed mode)
[root@centos8 ~]#which java
/usr/bin/java
[root@centos8 ~]#ll /usr/bin/java
lrwxrwxrwx 1 root root 22 Feb 8 20:03 /usr/bin/java -> /etc/alternatives/java
[root@centos8 ~]#ll /etc/alternatives/java
lrwxrwxrwx 1 root root 73 Feb 8 20:03 /etc/alternatives/java -> /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.232.b09-0.el8_0.x86_64/jre/bin/java
[root@centos8 ~]#rpm -qf /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.232.b09-0.el8_0.x86_64/jre/bin/java
java-1.8.0-openjdk-headless-1.8.0.232.b09-0.el8_0.x86_64- ubuntu 安装 openjdk
[root@ubuntu1804 ~]#apt update
[root@ubuntu1804 ~]#apt install openjdk-8-jdk -y
[root@ubuntu1804 ~]#java -version
openjdk version "1.8.0_242"
OpenJDK Runtime Environment (build 1.8.0_242-8u242-b08-0ubuntu3~18.04-b08)
OpenJDK 64-Bit Server VM (build 25.242-b08, mixed mode)安装oracle官方 JDK
- 使用Oracle官网的JDK 8的rpm安装
#官网下载：https://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html
[root@centos8 ~]#ls -lh jdk-8u241-linux-x64.rpm
-rw-r--r-- 1 root root 171M Feb 8 18:29 jdk-8u241-linux-x64.rpm
#安装jdk，无相关依赖包
[root@centos8 ~]#dnf -y install jdk-8u241-linux-x64.rpm
[root@centos8 ~]#java -version
java version "1.8.0_241"
Java(TM) SE Runtime Environment (build 1.8.0_241-b07)
Java HotSpot(TM) 64-Bit Server VM (build 25.241-b07, mixed mode)
#初始化环境变量
[root@centos8 ~]#vim /etc/profile.d/jdk.sh
[root@centos8 ~]#cat /etc/profile.d/jdk.sh
export JAVA_HOME=/usr/java/default
export JRE_HOME=JAVA_HOME/jre
export CLASSPATH=JAVA_HOME/lib/:JRE_HOME/lib/
export PATH=JAVA_HOME/bin:$PATH
[root@centos8 ~]#. /etc/profile.d/jdk.sh
#查看jdk信息
[root@centos8 ~]#which java
/usr/bin/java
[root@centos8 ~]#ll /usr/bin/java
lrwxrwxrwx 1 root root 22 Feb 8 18:35 /usr/bin/java -> /etc/alternatives/java
[root@centos8 ~]#ll /etc/alternatives/java
lrwxrwxrwx 1 root root 41 Feb 8 18:35 /etc/alternatives/java -> /usr/java/jdk1.8.0_241-amd64/jre/bin/java
[root@centos8 ~]#rpm -q --scripts jdk-8u241-linux-x64.rpm
#查看到安装目录为/user/java下
[root@centos8 ~]#rpm -ql jdk-8u241-linux-x64.rpm |less
warning: jdk-8u241-linux-x64.rpm: Header V3 RSA/SHA256 Signature, key ID ec551f03: NOKEY
/usr
/usr/java
/usr/java/jdk1.8.0_241-amd64
/usr/java/jdk1.8.0_241-amd64/.java
/usr/java/jdk1.8.0_241-amd64/.java/.systemPrefs
/usr/java/jdk1.8.0_241-amd64/.java/.systemPrefs/.system.lock
/usr/java/jdk1.8.0_241-amd64/.java/.systemPrefs/.systemRootModFile
/usr/java/jdk1.8.0_241-amd64/.java/init.d
......
[root@centos8 ~]#ll /usr/java/
total 0
lrwxrwxrwx 1 root root 16 Feb 8 18:35 default -> /usr/java/latest
drwxr-xr-x 8 root root 258 Feb 8 18:35 jdk1.8.0_241-amd64
lrwxrwxrwx 1 root root 28 Feb 8 18:35 latest -> /usr/java/jdk1.8.0_241-amd64
- 安装oracle官网的二进制文件
#下载安装包：https://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html
[root@centos8 ~]#tar xvf jdk-8u241-linux-x64.tar.gz -C /usr/local/
[root@centos8 ~]#cd /usr/local/
[root@centos8 ~]#ln -s jdk1.8.0_241/ jdk
#初始化环境变量
[root@centos8 ~]#vim /etc/profile.d/jdk.sh
[root@centos8 ~]#cat /etc/profile.d/jdk.sh
export JAVA_HOME=/usr/local/jdk
export JRE_HOME=JAVA_HOME/jre
export CLASSPATH=JAVA_HOME/lib/:JRE_HOME/lib/
export PATH=PATH:$JAVA_HOME/bin
[root@centos8 ~]#. /etc/profile.d/jdk.sh
#验证安装
[root@centos8 ~]#java -version
java version "1.8.0_241"
Java(TM) SE Runtime Environment (build 1.8.0_241-b07)
Java HotSpot(TM) 64-Bit Server VM (build 25.241-b07, mixed mode)
[root@centos8 ~]#which java
/usr/local/jdk/bin/java本文链接：http://www.yunweipai.com/35109.html
原创文章，作者：ItWorker，如若转载，请注明出处：https://blog.ytso.com/52732.html