命令行上显示了不同的Java版本 [英] Different Java version showing on command line

问题描述

我最近检查了我的Java版本.我运行命令java -version，发现我正在使用java version 1.7.0_09.但是，当我尝试检查C:\Program Files\Java\目录时，我似乎找不到相同的版本.我只看到以下内容:

I have recently checked on my Java version. I ran the command java -version and I found out that I was using java version 1.7.0_09. But when I tried to check on C:\Program Files\Java\ directory, I don't seem to find the same version. I only see the following:

• j2re1.4
• jdk1.6.0_32
• jdk1.7.0_06
• jdk1.7.0_07
• jre6
• jre7

依此类推...

我的程序仍在运行，但我只是尝试手动编译所有内容，并了解操作系统如何处理Java.

My programs still run, but I'm just trying to compile everything manually, and understand how Java is being treated by the OS.

另一件事很奇怪，我尝试检查环境变量设置，但它没有说明jdk1.7.0_09.

Another thing that is weird is, I tried to check on environment variable settings, and it does not say anything about jdk1.7.0_09.

路径:

• C:\ Program Files \ Common Files \ Microsoft Shared \ Windows Live；
• ％SystemRoot％\ system32;
• ％SystemRoot％;
• ％SystemRoot％\ System32 \ Wbem;
• ％SYSTEMROOT％\ System32 \ WindowsPowerShell \ v1.0 \;
• C:\ Program Files \ TortoiseSVN \ bin;
• C:\ Program Files \ Windows Live \ Shared;
• C:\ eclipse \ plugins \ com.google.appengine.eclipse.sdkbundle_1.6.5 \ appengine-java-sdk-1.6.5 \ bin;
• C:\ Program Files \ Java \ jdk1.7.0_07 \ bin; C:\ Program Files \ QuickTime \ QTSystem \;
• ％ANT_HOME％\ bin

• C:\Program Files\Common Files\Microsoft Shared\Windows Live;
• %SystemRoot%\system32;
• %SystemRoot%;
• %SystemRoot%\System32\Wbem;
• %SYSTEMROOT%\System32\WindowsPowerShell\v1.0\;
• C:\Program Files\TortoiseSVN\bin;
• C:\Program Files\Windows Live\Shared;
• C:\eclipse\plugins\com.google.appengine.eclipse.sdkbundle_1.6.5\appengine-java-sdk-1.6.5\bin;
• C:\Program Files\Java\jdk1.7.0_07\bin;C:\Program Files\QuickTime\QTSystem\;
• %ANT_HOME%\bin

只想让你们知道它以某种方式自动变成了jre.

Just want to let you guys know that it somehow automatically became a jre.

完整目录为C:\Users\User02\AppData\LocalLow\Sun\Java\jre1.7.0_09，仅得到名为lzma.dll的文件.

The complete directory is C:\Users\User02\AppData\LocalLow\Sun\Java\jre1.7.0_09 and it's just got the file named lzma.dll.

但是，我还有另一个目录，显示为C:\Users\User02\AppData\LocalLow\Sun\Java\jdk1.7.0_07.其中的文件是:

But, I have another directory that says C:\Users\User02\AppData\LocalLow\Sun\Java\jdk1.7.0_07. The files inside it are:

• jdk1.7.0_07.msi
• sj170070.cab
• ss170070.cab
• st170070.cab
• 和sz170070.cab

推荐答案

在计算机上可以并排放置许多JRE.

It's possible to have many JRE side-by-side on a computer.

如果在Windows上正确安装了JRE，则有关每个版本的信息都存储在注册表中.安装过程将在系统PATH(％SYSTEMROOT％\ System32 )中安装特殊的java.exe .因此，您无需更改PATH，因为此特殊的java.exe将找到当前的JRE.在命令行中，键入java -version以显示当前安装的jre版本.

If the JRE is properly installed on Windows, informations about each version are stored in the registry. The installation process installs a special java.exe in the system PATH (%SYSTEMROOT%\System32). So you don't need to alter you PATH because this special java.exe will find the current JRE. From a command line, type java -version to display the current jre version installed.

在1.6版中，现在可以选择与上一个版本不同的JRE安装，而无需进行任何注册表修改.

With release 1.6, it's now possible to select a different JRE installation than the last one without any registry modification.

JRE安装在注册表中的项

The JRE installation are listed in the registry in the key

HKEY_LOCAL_MACHINE \ SOFTWARE \ JavaSoft \ Java运行时环境

HKEY_LOCAL_MACHINE\SOFTWARE\JavaSoft\Java Runtime Environment

参加这个简单的测试课程

Take this simple test class

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

在安装了1.6和1.5的系统上.如果您输入

On a system, with 1.6 and 1.5 installed. If you type

> java ShowVersion

自从上次安装以来，大概将使用1.6 JRE.

It's probably the 1.6 JRE that will be used since it's the last installed.

要强制使用1.5 JRE，请使用此命令行.

To force the 1.5 JRE instead, use this command line.

> java -version:"1.5" ShowVersion

如果字节码与给定的JRE不兼容，那么..当然不起作用.

If the bytecode is incompatible with the given JRE then .. it won't work, of course.

ref: technote Java 6

您始终可以提供使用特定安装的完整路径.以这种方式启动JVM根本不使用注册表设置.

You can always give the complete path to use a specific installation. Launching the JVM this way does not use the registry setting at all.

>"C:\Program Files\Java\j2re1.4.1_02\bin\java" -version
java version "1.4.1_02"

source:从命令行中选择特定的JRE

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