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2023-02-14
CentOS8.2安装Java 14.0.2的教程详解
CentOS8.2安装Java 14.0.2的教程详解
java是一种安全，稳定且广为人知的通用编程语言和计算技术平台，具有许多相互关联的功能。
要运行基于Java的应用程序，必须在服务器上安装Java。您通常需要Java Runtime Environment（JRE），这是用于在linux机器上运行Java应用程序的软件组件的集合。
如果要开发Java的软件应用程序，则需要安装Oracle Java开发工具包（JDK），该工具包带有一个完整的JRE软件包，其中包含用于开发，调试和监视Java应用程序的工具，它是Oracle支持的Java SE（标准版）版本。
注意：如果您正在寻找开放源代码和免费的JDK版本，请安装OpenJDK，它在GPL许可下提供与Oracle JDK相同的功能和性能。
在撰写本文时，OpenJDK 11是要使用默认存储库中的以下命令安装的Java的当前LTS版本：
[1] 安装[java-11-openjdk]包，
如果需要编译器，也要安装[java-11-openjdk-devel]包。
[root@nfsclient ~]# dnf -y install java-11-openjdk java-11-openjdkXxHpaY-devel
Last metadata expiration check: 0:29:58 ago on Wed 09 Dec 2020 10:25:45 PM CST.
Dependencies resolved.
==============================================================================================================================
Package Architecture Version Repository Size
==============================================================================================================================
Installing:
java-11-openjdk x86_64 1:11.0.9.11-0.el8_2 AppStream 251 k
java-11-openjdk-devel x86_64 1:11.0.9.11-0.el8_2 AppStream 3.4 M
Installing dependencies:
copy-jdk-configs noarch 3.7-1.el8 AppStream 27 k
java-11-openjdk-headless x86_64 1:11.0.9.11-0.el8_2 AppStream 40 M
javapackages-filesystem noarch 5.3.0-1.module_el8.0.0+11+5b8c10bd AppStream 30 k
lksctp-tools x86_64 1.0.18-3.el8 base 100 k
ttmkfdir x86_64 3.0.9-54.el8 AppStream 62 k
tzdata-java noarch 2020d-1.el8 AppStream 190 k
xorg-x11-fonts-Type1 noarch 7.5-19.el8 AppStream 522 k
Enabling module streams:
javapackages-runtime 201801
Transaction Summary
==============================================================================================================================
[root@nfsclient ~]# java --version
openjdk 11.0.9 2020-10-20 LTS
OpenJDK Runtime Environment 18.9 (build 11.0.9+11-LTS)
OpenJDK 64-Bit Server VM 18.9 (build 11.0.9+11-LTS, mixed mode, sharing)
# verify to create test program
[root@nfsclient ~]# cat >/tmp/java_test.java< class java_test { public static void main(String[] args) { System.out.println("Hello Java World !"); } } EOF [root@dlp ~]# javac java_test.java [root@dlp ~]# java java_test Hello Java World ! 如果你从CentOS官方存储库中安装了多个版本的Java，你可以用其他的方法来切换它们。 [root@nfsclient ~]# java --version openjdk 11.0.5 2019-10-15 LTS OpenJDK Runtime Environment 18.9 (build 11.0.5+10-LTS) OpenJDK 64-Bit Server VM 18.9 (build 11.0.5+10-LTS, mixed mode, sharing) [root@dlp ~]# javac --version javac 11.0.5 [2]安装 jdk-14.0.2_linux-x64_bin.rpm [root@nfsclient tmp]# dnf -y install jdk-14.0.2_linux-x64_bin.rpm [root@nfsclient tmp]# java --version java 14.0.2 2020-07-14 Java(TM) SE Runtime Environment (build 14.0.2+12-46) Java HotSpot(TM) 64-Bit Server VM (build 14.0.2+12-46, mixed mode, sharing) [root@nfsclient tmp]# cat >/etc/profile.d/jdk14.sh < export JAVA_HOME=/usr/java/default export PATH=\$PATH:\$JAVA_HOME/bin EOF To use Java Home, source the file. [root@nfsclient tmp]# source /etc/profile.d/jdk14.sh 测试Java安装。 为了测试我们的Java安装，让我们创建一个简单的html文件。创建一个test.java文件，其内容如下 [root@nfsclient ~]# cat >/tmp/HelloWorld.java< public class HelloWorld { public static void main(String[] args) { System.out.println(“Hello, world”); } } EOF [root@nfsclient ~]# cat >/tmp/java_test01.java< clhttp://ass java_test { public static void main(String[] args) { System.out.println("Hello Java World !"); } } EOF [root@nfsclient ~]#javac java_test01.java [root@nfsclient ~]# java java_test01 Hello Java World ! 如果你从CentOS官方存储库中安装了多个版本的Java，你可以用其他的方法来切换它们。 [root@nfsclient tmp]# alternatives --config java There are 2 programs which provide 'java'. Selection Command ----------------------------------------------- 1 java-11-openjdk.x86_64 (/usr/lib/jvm/java-11-openjdk-11.0.9.11-0.el8_2.x86_64/bin/java) *+ 2 /usr/java/jdk-14.0.2/bin/java Enter to keep the current selection[+], or type selection number: 2 [root@nfsclient ~]#alternatives --config javac [root@nfsclient ~]# alternatives --install /usr/bin/javac javac /usr/java/jdk-14.0.2/bin/javac 100 [root@nfsclient tmp]# alternatives --config javac There are 2 programs which provide 'javac'. Selection Command ----------------------------------------------- 1 java-11-openjdk.x86_64 (/usr/lib/jvm/java-11-openjdk-11.0.9.11-0.el8_2.x86_64/bin/javac) *+ 2 /usr/java/jdk-14.0.2/bin/javac Enter to keep the current selection[+], or type selection number:
class java_test {
public static void main(String[] args) {
System.out.println("Hello Java World !");
}
}
EOF
[root@dlp ~]# javac java_test.java
[root@dlp ~]# java java_test
Hello Java World !
如果你从CentOS官方存储库中安装了多个版本的Java，你可以用其他的方法来切换它们。
[root@nfsclient ~]# java --version
openjdk 11.0.5 2019-10-15 LTS
OpenJDK Runtime Environment 18.9 (build 11.0.5+10-LTS)
OpenJDK 64-Bit Server VM 18.9 (build 11.0.5+10-LTS, mixed mode, sharing)
[root@dlp ~]# javac --version
javac 11.0.5
[2]安装 jdk-14.0.2_linux-x64_bin.rpm
[root@nfsclient tmp]# dnf -y install jdk-14.0.2_linux-x64_bin.rpm
[root@nfsclient tmp]# java --version
java 14.0.2 2020-07-14
Java(TM) SE Runtime Environment (build 14.0.2+12-46)
Java HotSpot(TM) 64-Bit Server VM (build 14.0.2+12-46, mixed mode, sharing)
[root@nfsclient tmp]# cat >/etc/profile.d/jdk14.sh < export JAVA_HOME=/usr/java/default export PATH=\$PATH:\$JAVA_HOME/bin EOF To use Java Home, source the file. [root@nfsclient tmp]# source /etc/profile.d/jdk14.sh 测试Java安装。 为了测试我们的Java安装，让我们创建一个简单的html文件。创建一个test.java文件，其内容如下 [root@nfsclient ~]# cat >/tmp/HelloWorld.java< public class HelloWorld { public static void main(String[] args) { System.out.println(“Hello, world”); } } EOF [root@nfsclient ~]# cat >/tmp/java_test01.java< clhttp://ass java_test { public static void main(String[] args) { System.out.println("Hello Java World !"); } } EOF [root@nfsclient ~]#javac java_test01.java [root@nfsclient ~]# java java_test01 Hello Java World ! 如果你从CentOS官方存储库中安装了多个版本的Java，你可以用其他的方法来切换它们。 [root@nfsclient tmp]# alternatives --config java There are 2 programs which provide 'java'. Selection Command ----------------------------------------------- 1 java-11-openjdk.x86_64 (/usr/lib/jvm/java-11-openjdk-11.0.9.11-0.el8_2.x86_64/bin/java) *+ 2 /usr/java/jdk-14.0.2/bin/java Enter to keep the current selection[+], or type selection number: 2 [root@nfsclient ~]#alternatives --config javac [root@nfsclient ~]# alternatives --install /usr/bin/javac javac /usr/java/jdk-14.0.2/bin/javac 100 [root@nfsclient tmp]# alternatives --config javac There are 2 programs which provide 'javac'. Selection Command ----------------------------------------------- 1 java-11-openjdk.x86_64 (/usr/lib/jvm/java-11-openjdk-11.0.9.11-0.el8_2.x86_64/bin/javac) *+ 2 /usr/java/jdk-14.0.2/bin/javac Enter to keep the current selection[+], or type selection number:
export JAVA_HOME=/usr/java/default
export PATH=\$PATH:\$JAVA_HOME/bin
EOF
To use Java Home, source the file.
[root@nfsclient tmp]# source /etc/profile.d/jdk14.sh
测试Java安装。
为了测试我们的Java安装，让我们创建一个简单的html文件。创建一个test.java文件，其内容如下
[root@nfsclient ~]# cat >/tmp/HelloWorld.java< public class HelloWorld { public static void main(String[] args) { System.out.println(“Hello, world”); } } EOF [root@nfsclient ~]# cat >/tmp/java_test01.java< clhttp://ass java_test { public static void main(String[] args) { System.out.println("Hello Java World !"); } } EOF [root@nfsclient ~]#javac java_test01.java [root@nfsclient ~]# java java_test01 Hello Java World ! 如果你从CentOS官方存储库中安装了多个版本的Java，你可以用其他的方法来切换它们。 [root@nfsclient tmp]# alternatives --config java There are 2 programs which provide 'java'. Selection Command ----------------------------------------------- 1 java-11-openjdk.x86_64 (/usr/lib/jvm/java-11-openjdk-11.0.9.11-0.el8_2.x86_64/bin/java) *+ 2 /usr/java/jdk-14.0.2/bin/java Enter to keep the current selection[+], or type selection number: 2 [root@nfsclient ~]#alternatives --config javac [root@nfsclient ~]# alternatives --install /usr/bin/javac javac /usr/java/jdk-14.0.2/bin/javac 100 [root@nfsclient tmp]# alternatives --config javac There are 2 programs which provide 'javac'. Selection Command ----------------------------------------------- 1 java-11-openjdk.x86_64 (/usr/lib/jvm/java-11-openjdk-11.0.9.11-0.el8_2.x86_64/bin/javac) *+ 2 /usr/java/jdk-14.0.2/bin/javac Enter to keep the current selection[+], or type selection number:
public class HelloWorld {
public static void main(String[] args) {
System.out.println(“Hello, world”);
}
}
EOF
[root@nfsclient ~]# cat >/tmp/java_test01.java< clhttp://ass java_test { public static void main(String[] args) { System.out.println("Hello Java World !"); } } EOF [root@nfsclient ~]#javac java_test01.java [root@nfsclient ~]# java java_test01 Hello Java World ! 如果你从CentOS官方存储库中安装了多个版本的Java，你可以用其他的方法来切换它们。 [root@nfsclient tmp]# alternatives --config java There are 2 programs which provide 'java'. Selection Command ----------------------------------------------- 1 java-11-openjdk.x86_64 (/usr/lib/jvm/java-11-openjdk-11.0.9.11-0.el8_2.x86_64/bin/java) *+ 2 /usr/java/jdk-14.0.2/bin/java Enter to keep the current selection[+], or type selection number: 2 [root@nfsclient ~]#alternatives --config javac [root@nfsclient ~]# alternatives --install /usr/bin/javac javac /usr/java/jdk-14.0.2/bin/javac 100 [root@nfsclient tmp]# alternatives --config javac There are 2 programs which provide 'javac'. Selection Command ----------------------------------------------- 1 java-11-openjdk.x86_64 (/usr/lib/jvm/java-11-openjdk-11.0.9.11-0.el8_2.x86_64/bin/javac) *+ 2 /usr/java/jdk-14.0.2/bin/javac Enter to keep the current selection[+], or type selection number:
clhttp://ass java_test {
public static void main(String[] args) {
System.out.println("Hello Java World !");
}
}
EOF
[root@nfsclient ~]#javac java_test01.java
[root@nfsclient ~]# java java_test01
Hello Java World !
如果你从CentOS官方存储库中安装了多个版本的Java，你可以用其他的方法来切换它们。
[root@nfsclient tmp]# alternatives --config java
There are 2 programs which provide 'java'.
Selection Command
-----------------------------------------------
1 java-11-openjdk.x86_64 (/usr/lib/jvm/java-11-openjdk-11.0.9.11-0.el8_2.x86_64/bin/java)
*+ 2 /usr/java/jdk-14.0.2/bin/java
Enter to keep the current selection[+], or type selection number: 2
[root@nfsclient ~]#alternatives --config javac
[root@nfsclient ~]# alternatives --install /usr/bin/javac javac /usr/java/jdk-14.0.2/bin/javac 100
[root@nfsclient tmp]# alternatives --config javac
There are 2 programs which provide 'javac'.
Selection Command
-----------------------------------------------
1 java-11-openjdk.x86_64 (/usr/lib/jvm/java-11-openjdk-11.0.9.11-0.el8_2.x86_64/bin/javac)
*+ 2 /usr/java/jdk-14.0.2/bin/javac
Enter to keep the current selection[+], or type selection number:
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