[英]Launch Java application (main) from specified directory
I have a very large/old/long running project that accesses file resources using paths that are relative to the launch directory (ie the application will only work if launched from a specific directory). 我有一个非常大/老/长期运行的项目,该项目使用相对于启动目录的路径访问文件资源(即,该应用程序仅在从特定目录启动时才起作用)。 When I need to debug the program I can launch it from eclipse and set the start directory using Run Configurations->->Working directory. 当我需要调试程序时,可以从Eclipse中启动它,并使用“运行配置”->->“工作目录”来设置开始目录。 I would like to be able to write a single Java class that will launch the main class from a specified directory. 我希望能够编写一个Java类,该类将从指定目录启动主类。 Is this possible and if it is how would I do it? 这可能吗,如果我会怎么做? I have found several related items including those shown below but can't seem to find the answer I'm looking for. 我发现了一些相关的项目,包括以下所示的项目,但似乎找不到我要的答案。
https://community.oracle.com/thread/1257595?start=0&tstart=0 https://community.oracle.com/thread/1257595?start=0&tstart=0
http://www.javapractices.com/topic/TopicAction.do?Id=243 http://www.javapractices.com/topic/TopicAction.do?Id=243
How do I run a java program from a different directory? 如何从其他目录运行Java程序?
Java - start another class' main in a different process Java-在不同的过程中启动另一个类的main
According to this you can write a simple class with main that: 根据这个你可以写与主要的是一个简单的类:
Ex. 例如
public class Exec
{
public static void main(String []args) throws Exception
{ choosenDir=askForWorkingDirectory()
jarFileNameWithabsolutePath=copyJarIntoDir(choosenDir)
Process ps=Runtime.getRuntime().exec(new String[]{"java","-jar",jarFileNameWithabsolutePath});
ps.waitFor();
java.io.InputStream is=ps.getInputStream();
byte b[]=new byte[is.available()];
is.read(b,0,b.length);
System.out.println(new String(b));
deleteJarFormChoosenDir(jarFileNameWithabsolutePath);
}
}
Where: 哪里:
askForWorkingDirectory() show a DirectoryChooser dialog and return the absolute path. askForWorkingDirectory()显示DirectoryChooser对话框并返回绝对路径。
copyJarIntoDir(choosenDir) receive the choosen directory where copy the jar file and returns the absolute path of the jar file with file name. copyJarIntoDir(choosenDir)接收选择的目录,在该目录中复制jar文件,并返回具有文件名的jar文件的绝对路径。
deleteJarFormChoosenDir(jarFileNameWithabsolutePath) finally remove the copied jar deleteJarFormChoosenDir(jarFileNameWithabsolutePath)最终删除复制的jar
Hope I helped you! 希望我能帮到您!
Using Runtime.getRuntime.exec with the optional runtime directory paramerter worked for me. 将Runtime.getRuntime.exec与可选的运行时目录参数配合使用对我来说很有效。
This is what I used: 这是我使用的:
public static void main(String[] args) throws Exception {
String classPath = getClassPath();
Runtime.getRuntime().exec("java -cp " + classPath + " com.mycompany.MyApp", null, MY_WORKING_DIR);
}
private static String getClassPath() {
StringBuffer buffer = new StringBuffer();
URLClassLoader urlClassLoader = ((URLClassLoader) (Thread.currentThread().getContextClassLoader()));
URL[] urls = urlClassLoader.getURLs();
for (URL url : urls) {
buffer.append(new File(url.getPath()));
buffer.append(System.getProperty("path.separator"));
}
String rtn = buffer.toString();
return rtn;
}
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