如何确定Windows Java安装位置 [英] How to determine Windows Java installation location

问题描述

我正在尝试从C＃程序集动态运行.jar（使用 Process.Start（info））。现在，从控制台应用程序我可以运行：

I'm trying to dynamically run a .jar from a C# assembly (using Process.Start(info)). Now, from a console application I am able to just run:

ProcessStartInfo info = new ProcessStartInfo("java", "-jar somerandom.jar");

但是，在程序集中，我不断收到 Win32Exception 系统无法找到指定的文件，并且必须将行更改为Java的完整路径，如下所示：

In an assembly, however, I keep getting a Win32Exception of "The system cannot find the file specified" and have to change the line to the full path of Java like so:

ProcessStartInfo info = new ProcessStartInfo("C:\\Program Files\\Java\\jre6\\bin\\java.exe", "-jar somerandom.jar");

这显然不行。我需要一种动态（但声明性地）确定Java的安装位置的方法。

This obviously won't do. I need a way to dynamically (but declaratively) determine the installed location of Java.

我开始考虑寻找注册表，但是当我到达那里时我注意到那里是版本的特定键，甚至不能保证它们是数字（例如HKEY_LOCAL_MACHINE\SOFTWARE\JavaSoft\Java Runtime Environment \1.6和HKEY_LOCAL_MACHINE\SOFTWARE \ JavaSoft \ Java运行时环境 \ 1.6.0_20）。

I started thinking of looking to the registry, but when I got there I noticed that there were specific keys for the versions and that they could not even be guaranteed to be numeric (e.g. "HKEY_LOCAL_MACHINE\SOFTWARE\JavaSoft\Java Runtime Environment\1.6" and "HKEY_LOCAL_MACHINE\SOFTWARE\JavaSoft\Java Runtime Environment\1.6.0_20").

从一个查找最新的java.exe路径的最可靠的长途解决方案是什么？ C＃申请？

What would be the most reliable "long-haul" solution to finding the most up-to-date java.exe path from a C# application?

非常感谢提前。

- 编辑 -

感谢 GenericTypeTea 和Stephen Cleary 的答案，我已解决了以下问题：

Thanks to a combination of GenericTypeTea's and Stephen Cleary's answers, I have solved the issue with the following:

private String GetJavaInstallationPath()
{
    String javaKey = "SOFTWARE\\JavaSoft\\Java Runtime Environment";
    using (var baseKey = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry64).OpenSubKey(javaKey))
    {
        String currentVersion = baseKey.GetValue("CurrentVersion").ToString();
        using (var homeKey = baseKey.OpenSubKey(currentVersion))
            return homeKey.GetValue("JavaHome").ToString();
    }
}

推荐答案

你可以通过注册表完成。你看错了地方。我为你敲了一个简单的例子：

You can do it through the registry. You were looking in the wrong place though. I knocked together a quick example for you:

private string GetJavaInstallationPath()
{
    string environmentPath = Environment.GetEnvironmentVariable("JAVA_HOME");
    if (!string.IsNullOrEmpty(environmentPath))
    {
       return environmentPath;
    }

    string javaKey = "SOFTWARE\\JavaSoft\\Java Runtime Environment\\";
    using (Microsoft.Win32.RegistryKey rk = Microsoft.Win32.Registry.LocalMachine.OpenSubKey(javaKey))
    {
        string currentVersion = rk.GetValue("CurrentVersion").ToString();
        using (Microsoft.Win32.RegistryKey key = rk.OpenSubKey(currentVersion))
        {
            return key.GetValue("JavaHome").ToString();
        }
    }
}

然后使用它，只需执行以下操作：

Then to use it, just do the following:

string installPath = GetJavaInstallationPath();
string filePath = System.IO.Path.Combine(installPath, "bin\\Java.exe");
if (System.IO.File.Exists(filePath))
{
    // We have a winner
}

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