Directory listing not refreshing
This is driving me crazy! I have a panel that displays a list of files from a directory. The list is stored in a vector. When I click on a button, a new file is created in the same directory and the list needs to be refreshed.
I don't understand why Java cannot see the new file, even though if I add a good old DIR in Dos, Dos can see the file. It's as if the new file is invisible even though I can see it and Dos can see it. I tried giving it some time (sleep, yield) but it's no use. I also tried copying to a new temp file and reading the temp but again to no avail. Here's some code (removed some irrelevant lines):
public class Button extends EncapsulatedButton {
public Button()
{
super("button pressed");
}
public void actionPerformed(ActionEvent arg0) {
//removed function here where the new file is created in the directory
//remove call to DOS that regenerates /myFileList.txt after a new file was added in the directory
//at this point, DOS can see the new file and myFileList.txt is updated, however it is read by java without the update!!!!!
//now trying to read the directory after the new file was created
Vector data = new Vector<String>();
String s = null;
// Create the readers to read the file.
try {
File f = new File("/myFileList.txt");
BufferedReader stream = new BufferedReader(new InputStreamReader(new FileInputStream(f)));
while((s = stream.readLine()) != null)
{
data.addElement(s.trim());
}
stream.close();
} catch (IOException e) {
e.printStackTrace();
}
util();
}
void util(){
//giving it time is not helping
Thread.yield();
try {
Thread.sleep(10000);
} catch (InterruptedException e1) {
e1.printStackTrace();
}
//get the file listing through java instead of DOS - still invisible
File fLocation = new File("/myDir");
File[] filesFound = fLocation.listFiles();
for (int i = 0; i < filesFound.length; i++) {
if (filesFound[i].isFile()) {
System.out.println("**********" + filesFound[i].getName());
}
}
//last resort: copy to a temp then read from there - still not good
try{
//copy to a temp file
File inputFile = new File("/myFileList.txt");
File outputFile = new File("/myFileList_temp.txt");
FileReader in = new FileReader(inputFile);
FileWriter out = new FileWriter(outputFile);
int c;
while ((c = in.read()) != -1)
out.write(c);
in.close();
out.close();
//read the copy to see if it is updated
// Open the file that is the first
// command line parameter
FileInputStream fstream = new FileInputStream("/myFileList_temp.txt");
// Get the object of DataInputStream
DataInputStream in1 = new DataInputStream(fstream);
BufferedReader br = new BufferedReader(new InputStreamReader(in1));
String strLine;
//Read File Line By Line
while ((strLine = br.readLine()) != null) {
// Print the content on the console
开发者_如何学Go System.out.println ("Test file read: " + strLine);
}
//Close the input stream
in1.close();
}catch (Exception e){//Catch exception if any
System.err.println("Error: " + e.getMessage());
}
}
}
I would appreciate any leads. Thank you.
myFileList.txt lokks like this:
myline1
myline2
myline3
After adding a new file in the folder,
myline4 should appear in it, then it will be read and displayed in the panel.
Honestly, your code is a mess.
You read from /myFileList.txt
and do nothing with what you read, except store it in a temporary Vector
. At best, this has no effect; at worst (if the file doesn't exist, for example) it throws an exception. Whatever it does, it does not create a new file.
Furthermore, I see no reference to the panel in your GUI that supposedly displays the file list. How do you expect it to get updated?
This works for me: To refresh the directory list, call .listFiles() again.
filesFound = fLocation.listFiles(); should show the most updated directory listing. Hope this helps you.
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