脚本适用于32/64位Windows。

@echo off

setlocal enabledelayedexpansion

::- Get the Java Version
set KEY="HKLM\SOFTWARE\JavaSoft\Java Runtime Environment"
set KEY64="HKLM\SOFTWARE\WOW6432Node\JavaSoft\Java Runtime Environment"
set VALUE=CurrentVersion
reg query %KEY% /v %VALUE% 2>nul || (
    set KEY=!KEY64!
    reg query !KEY! /v %VALUE% 2>nul || (
    echo JRE not installed 
    exit /b 1
)
)

set JRE_VERSION=
for /f "tokens=2,*" %%a in ('reg query %KEY% /v %VALUE% ^| findstr %VALUE%') do (
    set JRE_VERSION=%%b
)

echo JRE VERSION: %JRE_VERSION%

::- Get the JavaHome
set KEY="HKLM\SOFTWARE\JavaSoft\Java Runtime Environment\%JRE_VERSION%"
set KEY64="HKLM\SOFTWARE\WOW6432Node\JavaSoft\Java Runtime Environment\%JRE_VERSION%"
set VALUE=JavaHome
reg query %KEY% /v %VALUE% 2>nul || (
    set KEY=!KEY64!
    reg query !KEY! /v %VALUE% 2>nul || (
    echo JavaHome not installed
    exit /b 1
)
)

set JAVAHOME=
for /f "tokens=2,*" %%a in ('reg query %KEY% /v %VALUE% ^| findstr %VALUE%') do (
    set JAVAHOME=%%b
)

echo JavaHome: %JAVAHOME%

endlocal

如果需要的话，我通过在64位和32位注册表中测试注册表键来改进上面munsingh的答案:

::- Test for the registry location  
SET VALUE=CurrentVersion
SET KEY_1="HKLM\SOFTWARE\JavaSoft\Java Development Kit"
SET KEY_2=HKLM\SOFTWARE\JavaSoft\JDK
SET REG_1=reg.exe
SET REG_2="C:\Windows\sysnative\reg.exe"
SET REG_3="C:\Windows\syswow64\reg.exe"

SET KEY=%KEY_1%
SET REG=%REG_1%
%REG% QUERY %KEY% /v %VALUE% 2>nul
IF %ERRORLEVEL% EQU 0 GOTO _set_value

SET KEY=%KEY_2%
SET REG=%REG_1%
%REG% QUERY %KEY% /v %VALUE% 2>nul
IF %ERRORLEVEL% EQU 0 GOTO _set_value

::- %REG_2% is for 64-bit installations, using "C:\Windows\sysnative"
SET KEY=%KEY_1%
SET REG=%REG_2%
%REG% QUERY %KEY% /v %VALUE% 2>nul
IF %ERRORLEVEL% EQU 0 GOTO _set_value

SET KEY=%KEY_2%
SET REG=%REG_2%
%REG% QUERY %KEY% /v %VALUE% 2>nul
IF %ERRORLEVEL% EQU 0 GOTO _set_value

::- %REG_3% is for 32-bit installations on a 64-bit system, using "C:\Windows\syswow64"
SET KEY=%KEY_1%
SET REG=%REG_3%
%REG% QUERY %KEY% /v %VALUE% 2>nul
IF %ERRORLEVEL% EQU 0 GOTO _set_value

SET KEY=%KEY_2%
SET REG=%REG_3%
%REG% QUERY %KEY% /v %VALUE% 2>nul
IF %ERRORLEVEL% EQU 0 GOTO _set_value

:_set_value
FOR /F "tokens=2,*" %%a IN ('%REG% QUERY %KEY% /v %VALUE%') DO (
    SET JDK_VERSION=%%b
)
SET KEY=%KEY%\%JDK_VERSION%
SET VALUE=JavaHome
FOR /F "tokens=2,*" %%a IN ('%REG% QUERY %KEY% /v %VALUE%') DO (
    SET JAVAHOME=%%b
)
ECHO "%JAVAHOME%"
::- SETX JAVA_HOME "%JAVAHOME%"

访问64位注册表的参考

#!/bin/bash

if [[ $(which ${JAVA_HOME}/bin/java) ]]; then
    exe="${JAVA_HOME}/bin/java"
elif [[ $(which java) ]]; then
    exe="java"
else 
    echo "Java environment is not detected."
    exit 1
fi

${exe} -version

windows:

@echo off
if "%JAVA_HOME%" == "" goto nojavahome

echo Using JAVA_HOME            :   %JAVA_HOME%

"%JAVA_HOME%/bin/java.exe" -version
goto exit

:nojavahome
echo The JAVA_HOME environment variable is not defined correctly
echo This environment variable is needed to run this program.
goto exit

:exit

这个链接可能有助于解释如何从bash中找到java可执行文件:http://srcode.org/2014/05/07/detect-java-executable/

从命令行运行这个程序:

// File: Main.java
public class Main {

    public static void main(String[] args) {
       System.out.println(System.getProperty("java.home"));
    }

}


$ javac Main.java
$ java Main

这是特定于操作系统的。在Unix:

which java

将显示可执行文件的路径。我不知道Windows中是否有类似的，但你通常在系统PATH中有JDK安装的bin文件夹:

echo %PATH%

在Windows的命令提示符

在javac