如果 Windows 有多个 JRE 版本，如何在命令提示符下获取最新的 JRE 版本

Question

我正在尝试使用dir 命令在 Windows 中安装最新的 JRE。我在 Windows 上安装了 JRE 1.6 和 1.8，但我需要在 Windows 中安装最新版本（即使将来它可能会更改为 1.8 到 2.0*）。任何人都可以帮助解决这个问题。

Answer 1

在win7上试试这个批次

@echo off



@echo off
rem http://technet.microsoft.com/en-us/library/bb490890.aspx
SETLOCAL EnableDelayedExpansion
:: findJDK.bat

rem start:-> Run a command in a separate process, or run a file with its default associated application
rem REGEDIT.EXE: -> Export to a (.REG) file: 
rem REGEDIT.EXE [ /L:system | /R:user ] /E exportfile.REG "registry_key"

start /w regedit /e reg1.txt "HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\JavaSoft\Java Development Kit" 

rem TYPE: -> Display text file content in console
rem FIND: -> Search files or standard output

rem reserved key words regarding reg-key -> "JavaHome" "MicroVersion" "RuntimeLib"
rem | Reads the output from one command and writes it to the input of another command. Also known as a pipe. 

type reg1.txt | find "JavaHome" > reg2.txt 

if errorlevel 1 goto ERROR 
for /f "tokens=2 delims==" %%x in (reg2.txt) do (
  set JavaTemp=%%~x
  echo Regedit: JAVA_HOME path : !JavaTemp!
)

if errorlevel 1 goto ERROR
echo.
set JAVA_HOME=%JavaTemp%
set JAVA_HOME=%JAVA_HOME:\\=\%
echo JAVA_HOME was found to be %JAVA_HOME%



start /w regedit /e reg3.txt "HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\JavaSoft\Java Runtime Environment" 
type reg3.txt | find "RuntimeLib" > reg4.txt 
if errorlevel 1 goto ERROR 
for /f "tokens=2 delims==" %%x in (reg4.txt) do (
  set JavaTemp=%%~x
  echo Regedit: JRE_HOME path : !JavaTemp!
)
if errorlevel 1 goto ERROR
echo.
set JRE_HOME=%JavaTemp%
set JRE_HOME=%JRE_HOME:\\=\%
echo JRE_HOME was found to be %JRE_HOME%
goto END
:ERROR
echo A reg1.txt is: & type reg1.txt
echo B reg2.txt is: & type reg2.txt
echo
:END
echo END

pause

Answer 2

java -version:1.8.0_101 -jar jarname.jar 

在此处使用上述方式调用 java，您可以提供要使用的 java 版本，以防您的路径中有多个。