Docker中的Java 11 Shebang示例

怼烎@ 2023-02-15 01:28 6阅读 0赞

在Java 11中， [JEP 330][]添加了对直接运行单文件源代码的支持。

Terminal

# Before Java 11
    $ javac Hello.java
    $ java Hello
    
    # Now Java 11
    $ java Hello.java

这间接支持Java单文件程序使用Unix [Shebang][]作为脚本运行。 例如，在`.sh`文件下运行，将打印`Hello World!` 。

run.sh

#!/opt/java/openjdk/bin/java --source 11
    public class SheBang {
    
        public static void main(String[] args) {
    
            System.out.println("Hello World!");
    
        }
    }

*PS确保`!#`指向正确的`java` 。*

## 在Docker中测试 ##

由于我手头没有Linux，因此该示例将在Windows上进行测试，使用Docker镜像`adoptopenjdk/openjdk11:alpine` 。

本示例使用`run.sh`文件将Java程序作为外壳程序脚本运行。 阅读注释以进行自我解释。

Windows

# This is Windows command prompt
    
    # first run, it will take some time to download the image
    # run alpine with openjdk11 installed, and start shell sh
    > docker run -it adoptopenjdk/openjdk11:alpine sh
    
    # done, enter the shell automatically
    / #
    
    # make sure Java installed
    / # java -version
    openjdk version "11.0.7" 2020-04-14
    OpenJDK Runtime Environment AdoptOpenJDK (build 11.0.7+10)
    OpenJDK 64-Bit Server VM AdoptOpenJDK (build 11.0.7+10, mixed mode)
    
    # find out where is java
    / # which java
    /opt/java/openjdk/bin/java
    
    / # nano
    sh: nano: not found
    
    # we need an editor, apk install nano
    / # apk add nano
    
    / # nano run.sh

把这个

run.sh

#!/opt/java/openjdk/bin/java --source 11
    public class SheBang {
    
        public static void main(String[] args) {
    
            System.out.println("Hello World!");
    
        }
    }

Windows

# still inside container
    # assign execute permission
    / # chmod +x run.sh
    
    # run it, done.
    / # ./run.sh
    Hello World!
    
    # bye
    / # exit

## 参考文献 ##

*  [九月330][JEP 330]
 *  [舍邦（Unix）][Shebang]

标签： [docker][] [java 11][] [linux][] [shebang][] [shell脚本][shell]

> 翻译自: [https://mkyong.com/java/java-11-shebang-example-in-docker/][https_mkyong.com_java_java-11-shebang-example-in-docker]

[JEP 330]: https://openjdk.java.net/jeps/330
[Shebang]: https://en.wikipedia.org/wiki/Shebang_%28Unix%29
[docker]: https://mkyong.com/tag/docker/
[java 11]: https://mkyong.com/tag/java-11/
[linux]: https://mkyong.com/tag/linux-2/
[shebang]: https://mkyong.com/tag/shebang/
[shell]: https://mkyong.com/tag/shell-script/
[https_mkyong.com_java_java-11-shebang-example-in-docker]: https://mkyong.com/java/java-11-shebang-example-in-docker/