如何检测是否安装了 Java 运行时
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How to detect whether Java runtime is installed or not
提问by Hazem
I program windows applications using Java and this builds a ".jar" file not an ".exe" file. When a client computer with no java runtime installed opens the ".jar" file, it runs as an archive with winrar. All I want to know is how to detect whether java runtime is installed or not on a computer using c# code in order to show a MessageBox telling user to install java runtime, or launches the ".jar" file using the java runtime if it's installed.
我使用 Java 编写 Windows 应用程序，这会构建一个“.jar”文件而不是“.exe”文件。当未安装 java 运行时的客户端计算机打开“.jar”文件时，它会作为带有 winrar 的存档运行。我只想知道如何使用 c# 代码检测计算机上是否安装了 java 运行时，以显示 MessageBox 告诉用户安装 java 运行时，或者如果安装了 java 运行时则使用 java 运行时启动“.jar”文件.
回答by h4rp0
You can check the registry
您可以检查注册表
RegistryKey rk = Registry.LocalMachine;
RegistryKey subKey = rk.OpenSubKey("SOFTWARE\JavaSoft\Java Runtime Environment");
string currentVerion = subKey.GetValue("CurrentVersion").ToString();
回答by user1536307
Start 'java -version' in a childprocess. Check exitcode and returned output for versioninfo
在子进程中启动“java -version”。检查退出代码并返回版本信息的输出
List<String> output = new List<string>();
private bool checkIfJavaIsInstalled()
{
bool ok = false;
Process process = new Process();
try
{
process.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
process.StartInfo.CreateNoWindow = true;
process.StartInfo.FileName = "cmd.exe";
process.StartInfo.UseShellExecute = false;
process.StartInfo.RedirectStandardOutput = true;
process.StartInfo.RedirectStandardError = true;
process.StartInfo.Arguments = "/c \"" + "java -version " + "\"";
process.OutputDataReceived += new DataReceivedEventHandler((s, e) =>
{
if (e.Data != null)
{
output.Add((string) e.Data);
}
});
process.ErrorDataReceived += new DataReceivedEventHandler((s, e) =>
{
if (e.Data != null)
{
output.Add((String) e.Data);
}
});
process.Start();
process.BeginOutputReadLine();
process.BeginErrorReadLine();
process.WaitForExit();
ok = (process.ExitCode == 0);
}
catch
{
}
return (ok);
}
回答by Brian Agnew
You could check in the registry. This will tell you if you have a JRE, and which version.
您可以在注册表中查看。这将告诉您是否有 JRE，以及哪个版本的.
From this document:
从这个文件：
HKEY_LOCAL_MACHINE\Software\JavaSoft\Java Runtime Environment\<version number>
HKEY_LOCAL_MACHINE\Software\JavaSoft\Java Development Kit\<version number>
where the includes the major, minor and the patch version numbers; e.g., 1.4.2_06
其中包括主要、次要和补丁版本号；例如，1.4.2_06
回答by Thorbj?rn Ravn Andersen
A small applet in a html page which cancels a redirect to a "Please install Java" page.
html 页面中的一个小小程序，它取消对“请安装 Java”页面的重定向。
EDIT: This is almost the only really bullet-proof way. Any registry key containing JavaSoft is most likely only for the Sun JVM and not any other (like IBM or BEA).
编辑：这几乎是唯一真正防弹的方法。任何包含 JavaSoft 的注册表项很可能仅适用于 Sun JVM，而不适用于任何其他（如 IBM 或 BEA）。
