java: keep tracking of file size on the run?
I wrote a code that writes compressed objects into a file, My question开发者_如何转开发s is: is there a way that I could keep track of the increment of size of my file as the object being wrote in? here is my code:
public static void storeCompressedObjs(File outFile, ArrayList<Object[]> obj) {
FileOutputStream fos = null;
GZIPOutputStream gz = null;
ObjectOutputStream oos = null;
try {
fos = new FileOutputStream(outFile);
gz = new GZIPOutputStream(fos);
oos = new ObjectOutputStream(gz);
for (Object str : obj) {
oos.writeObject(str);
oos.flush();
//I was hoping to print outFile.length() here, but it doesn't work
}
} catch (IOException e) {
e.printStackTrace();
} finally {
oos.close();
gz.close();
fos.close();
}
}
I tried to use flush
after every oos.writeObject(str);
and then get the file size by using outFile.length()
, but no matter how much I flush it, the file size remain unchanged until the last jump to its final size. Anyway that I could fix it? Thanks
The Apache Commons project provides a class CountingOutputStream, which you can put into your chain of OutputStream
s. You can even have two of them:
package so5997784;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.util.zip.GZIPOutputStream;
import org.apache.commons.io.output.CountingOutputStream;
public class CountBytes {
private static void dump(File outFile, Object... objs) throws IOException {
FileOutputStream fos = new FileOutputStream(outFile);
try {
CountingOutputStream compressedCounter = new CountingOutputStream(fos);
OutputStream gz = new GZIPOutputStream(compressedCounter);
CountingOutputStream uncompressedCounter = new CountingOutputStream(gz);
ObjectOutputStream oos = new ObjectOutputStream(uncompressedCounter);
for (Object obj : objs) {
oos.writeObject(obj);
oos.flush();
System.out.println(uncompressedCounter.getByteCount() + " -> " + compressedCounter.getByteCount());
}
oos.close();
System.out.println(uncompressedCounter.getByteCount() + " -> " + compressedCounter.getByteCount());
} finally {
fos.close();
}
}
public static void main(String[] args) throws IOException {
File outFile = new File("objects.out.gz");
dump(outFile, "a", "b", "cde", "hello", "world");
}
}
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