java - 如何将 java 代码嵌入到批处理脚本中？是否可以创建 .java/.bat 混合体？

Question

虽然有一些技术可以让您创建 perfect (而不是 perfect )批处理文件与一些“本地”Windows 脚本语言混合。

“完美”的混合体应该是什么样子:

1. 嵌入的代码必须是可用的，你应该有能力将其复制粘贴到您想要的任何其他编辑器/IDE 中。应该有没有对临时文件和奇怪的转义序列的无休止的回声。(而是对于支持多行注释的每种语言都是可能的)。
2. 没有错误消息的“有毒”打印(例如 /* 将打印错误在命令提示符下尽管批处理将继续在下一行)
3. 没有临时文件。编译后的二进制文件除外对于没有翻译的语言来说，这是不可避免的。

是否有可能创建“完美”的 java/batch 混合体？

Answer 1

答案差不多。

主要障碍是我知道的所有编译器都对文件扩展名非常严格，并且会拒绝编译任何没有 .java 扩展名的文件。

由于批处理文件中以@开头的任何命令都不会显示，我们可以使用java注释来消除来自java注释的错误消息(应该用.bat保存 扩展名):

@Deprecated /* >nul 2>&1

:: self compiled java/.bat hybrid
::
:: deprecated is the only one annotation that can be used outside the class definition
:: and is needed for 'mute' start of multi-line java comment
:: that will be not printed by the batch file.
:: though it still creates two files - the .class and the .java
:: it still allows you to embed both batch and java code into one file

@echo off
setlocal
java -version >nul 2>&1 || (
    echo java not found
    exit /b 1
)

::find class name
::can be different than the script name
for /f "usebackq tokens=3 delims=} " %%c in (`type %~f0 ^|find /i "public class"^|findstr /v "for /f"`) do (
    set "javaFile=%%c"
    goto :skip
)
:skip

copy "%~f0" "%javaFile%.java" >nul 2>&1

javac "%javaFile%.java" 
java "%javaFile%"

::optional
::del %javaFile%.* >nul 2>&1 
end local
exit /b 0

*******/



public class TestClass
{
    public static void main(String args[])
    {
       System.out.println("selfcompiled .bat/.java hybrid");
    }
}

上面的示例涵盖了第 1 点和第 2 点。但是当然仍然需要创建 .java 文件。仍然复制比逐行回显 java 内容更快。

更进一步(或半步)- 使.java 扩展的行为类似于.bat(或几乎)

假设您不喜欢代码中查找 java 类名和自复制代码的部分。您可以使 .java 扩展名像 .bat 文件一样工作。或者几乎 - %0 将丢失，文件名将存储在 %1 中。为此，您需要使用管理员权限调用此批处理文件:

   @echo off
   :: requires Admin permissions
   :: allows a files with .JAVA (in this case ) extension to act like .bat/.cmd files.
   :: Will create a 'caller.bat' asociated with the extension
   :: which will create a temp .bat file on each call (you can consider this as cheating)
   :: and will call it.
   :: Have on mind that the %0 argument will be lost.


    rem :: "installing" a caller.
    if not exist "c:\javaCaller.bat" (
       echo @echo off
       echo copy "%%~nx1"  "%%temp%%\%%~nx1.bat" /Y ^>nul
       echo "%%temp%%\%%~nx1.bat"  %%*
    ) > c:\javaCaller.bat

    rem :: associating file extension
    assoc .java=javafile
    ftype javafile=c:\javaCaller "%%1" %%*

然后自编译的.java文件是这样的(应该以.java扩展名保存):

@Deprecated /* >nul 2>&1


:: requires ran javaExtInstaller.bat
:: https://github.com/npocmaka/batch.scripts/blob/master/Java/javaExtInstaller.bat
:: 
:: self compiled java/.bat hybrid
::
:: deprecated is the only one annotation that can be used outside the class definition
:: and is needed for 'mute' start of multi-line java comment
:: that will be not printed by the batch file.
:: allows you to embed both batch and java code into one file

@echo off

setlocal
java -version >nul 2>&1 || (
    echo java not found
    exit /b 1
)


if not exist "%~n1.class" javac "%~nx1" 

:: to compile the class every time use:
:: javac "%~nx1" 

java "%~n1"


endlocal
exit /b 0

*******/



public class TestClass
{
    public static void main(String args[])
    {
       System.out.println("selfcompiled .bat/.java hybrid");
    }
}

javaCaller.bat 仍然会创建临时 .bat 文件，但它不会“可见”并且批处理部分要短得多。

示例中没有包，因为只使用了一个 java 文件。包只会让示例更难理解。