import java.awt.*;
import java.util.*;
import java.io.*;
public class SingleApp extends Frame
{
public static void main(String args[])
{
if(isRunned("SingleApp"))
return;
SingleApp instance =new SingleApp();
Label lb=new Label("dsfsaf");
instance.add(lb);
instance.setSize(400,400);
instance.setVisible(true);
}
private static synchronized boolean isRunned(String filename)
{
String fname=System.getProperty("user.home");
fname = fname+File.separator+filename+".exist";
System.out.println(fname);
File ftmp=new File(fname);
try
{
if(ftmp.exists())
return true;
else
{
ftmp.createNewFile();
ftmp.deleteOnExit();
return false;
}
}
catch(IOException e)
{
return false;
}
}
}
限制窗口的唯一性, 什么意思?
import java.util.*;
import java.io.*;
public class SingleApp extends Frame
{
public static void main(String args[])
{
if(isRunned("SingleApp"))
return;
SingleApp instance =new SingleApp();
Label lb=new Label("dsfsaf");
instance.add(lb);
instance.setSize(400,400);
instance.setVisible(true);
}
private static synchronized boolean isRunned(String filename)
{
String fname=System.getProperty("user.home");
fname = fname+File.separator+filename+".exist";
System.out.println(fname);
File ftmp=new File(fname);
try
{
if(ftmp.exists())
return true;
else
{
ftmp.createNewFile();
ftmp.deleteOnExit();
return false;
}
}
catch(IOException e)
{
return false;
}
}
}
限制窗口的唯一性, 什么意思?
解决方案 »
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