批处理脚本，以检查系统中是否存在Java主程序，并检查java版本

Question

是否有任何方法可以编写aa批处理脚本来检查java home是否存在于环境中以及java版本是否在7之上？

@echo off
IF "%JAVA_HOME%" == "" (
    echo Enter path to JAVA_HOME: 
    set /p JAVA_HOME=
) ELSE (
    echo %JAVA_HOME%
)

我使用上面的脚本来检查java home.But，它没有给出任何适当的输出。

Answer 1

编辑了 2017/11/16以适应新的JRE注册表位置。原来的答案在线下

@echo off 
    setlocal enableextensions disabledelayedexpansion

    :: for variables
    ::    %%L = possible locations under HKLM\SOFTWARE of JavaSoft registry data
    ::          note: the list includes native and redirected locations
    ::    %%J = possible locations under %%L where to find the JRE information
    ::          note: the list is sorted from newer to older locations
    ::    %%k = The generated JRE root key to check
    ::    %%v = current java version
    ::    %%e = path to java    

    for %%L in ( 
        "" "Wow6432Node\" 
    ) do for %%J in ( 
        "JRE" "Java Runtime Environment"
    ) do if not defined javaDir (
        for %%k in (
            "HKLM\SOFTWARE\%%~LJavaSoft\%%~J"
        ) do for /f "tokens=3" %%v in (
            'reg query "%%~k" /v "CurrentVersion" 2^>nul ^| find /i "CurrentVersion"'
        ) do for /f "tokens=2,*" %%d in (
            'reg query "%%~k\%%v" /v "JavaHome"   2^>nul ^| find /i "JavaHome"'
        ) do ( set "javaDir=%%~e" & set "javaVersion=%%v" )
    )

    if not defined javaDir (
        echo Java not found
    ) else (
        echo JAVA_HOME="%javaDir%"
        echo JAVA_VERSION="%javaVersion%"
    )

    pause

原始答案

if defined JAVA_HOME (
    echo JAVA_HOME="%JAVA_HOME%"
) else (
    echo JAVA_HOME is not defined 
)

但是，这不会告诉您(也不会询问用户)是否安装了java或它是什么版本。

如果安装了java，您可以问windows (它存储在注册表中)它在哪里，有什么版本？

@echo off 
    setlocal enableextensions disabledelayedexpansion

    :: possible locations under HKLM\SOFTWARE of JavaSoft registry data
    set "javaNativeVersion="
    set "java32ON64=Wow6432Node\"

    :: for variables
    ::    %%k = HKLM\SOFTWARE subkeys where to search for JavaSoft key
    ::    %%j = full path of "Java Runtime Environment" key under %%k
    ::    %%v = current java version
    ::    %%e = path to java

    set "javaDir="
    set "javaVersion="
    for %%k in ( "%javaNativeVersion%" "%java32ON64%") do if not defined javaDir (
        for %%j in (
            "HKLM\SOFTWARE\%%~kJavaSoft\Java Runtime Environment"
        ) do for /f "tokens=3" %%v in (
            'reg query "%%~j" /v "CurrentVersion" 2^>nul ^| find /i "CurrentVersion"'
        ) do for /f "tokens=2,*" %%d in (
            'reg query "%%~j\%%v" /v "JavaHome"   2^>nul ^| find /i "JavaHome"'
        ) do ( set "javaDir=%%~e" & set "javaVersion=%%v" )
    )

    if not defined javaDir (
        echo Java not found
    ) else (
        echo JAVA_HOME="%javaDir%"
        echo JAVA_VERSION="%javaVersion%"
    )

    endlocal
    pause