my app downloads a zip with about 350 files. A mix of JPG and HTML files. The function i wrote to do it works just fine but the unzipping takes for ever. At first i thought the reason might be that writing to the sd-card is slow. but when i unzip the same zip with an other app on my phone it works much faster. is there anything that i could do to optimize it?
here is the code:
private void extract() {
try {
FileInputStream inStream = new FileInputStream(targetFilePath);
ZipInputStream zipStream = new ZipInputStream(new BufferedInputStream(inStream));
ZipEntry entry;
ZipFile zip = new ZipFile(targetFilePath);
//i know the contents for the zip so i create the dirs i need in advance
new File(targetFolder).mkdirs();
new File(targetFolder + "META-INF").mkdir();
new File(targetFolder + "content").mkdir();
int extracted = 0;
while((entry = zipStream.getNextEntry()) != null) {
if (entry.isDirectory()) {
new File(targetFolder + entry.getName()).mkdirs();
} else {
FileOutputStream outStream = new FileOutputStream(targetFolder + entry.getName());
for (int c = zipStream.read(); c != -1; c = zipStream.read()) {
outStream.write(c);
}
zipStream.closeEntry();
outStream.close();
extracted ++;
}
publishProgress(""+(int)extracted*100/zip.size());
}
zipStream.close();
inStream.close();
//
new File(targetFilePath).delete();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
thanks to CommonsWare i modified my code like this:
int size;
byte[] buffer = new byte[2048];
FileOutputStream outStream = new FileOutputStream(targetFolder + entry.getName());
BufferedOutputStream bufferOut = new BufferedOutputStream(outStream, buffer.length);
while((size = zipStream.read(buffer, 0, buffer.length)) != -1) {
bufferOut.write(buffer, 0, size);
}
bufferOut.flush();
bufferOut.close();
big performance difference. Thanks a lot.
You are reading and writing a byte at a time. Consider reading and writing a larger block at a time.
Just use this method once and believe me its a super fast process.. It will unzip all the files without skipping any file with in 1 second.
public boolean rajDhaniSuperFastUnzip(String inputZipFile, String destinationDirectory)
{
try {
int BUFFER = 2048;
List<String> zipFiles = new ArrayList<String>();
File sourceZipFile = new File(inputZipFile);
File unzipDestinationDirectory = new File(destinationDirectory);
unzipDestinationDirectory.mkdir();
ZipFile zipFile;
zipFile = new ZipFile(sourceZipFile, ZipFile.OPEN_READ);
Enumeration<?> zipFileEntries = zipFile.entries();
while (zipFileEntries.hasMoreElements()) {
ZipEntry entry = (ZipEntry) zipFileEntries.nextElement();
String currentEntry = entry.getName();
File destFile = new File(unzipDestinationDirectory, currentEntry);
if (currentEntry.endsWith(".zip")) {
zipFiles.add(destFile.getAbsolutePath());
}
File destinationParent = destFile.getParentFile();
destinationParent.mkdirs();
try {
if (!entry.isDirectory()) {
BufferedInputStream is =
new BufferedInputStream(zipFile.getInputStream(entry));
int currentByte;
byte data[] = new byte[BUFFER];
FileOutputStream fos = new FileOutputStream(destFile);
BufferedOutputStream dest =
new BufferedOutputStream(fos, BUFFER);
while ((currentByte = is.read(data, 0, BUFFER)) != -1) {
dest.write(data, 0, currentByte);
}
dest.flush();
dest.close();
is.close();
}
} catch (IOException ioe) {
ioe.printStackTrace();
}
}
zipFile.close();
for (Iterator<String> iter = zipFiles.iterator(); iter.hasNext();) {
String zipName = (String)iter.next();
doUnzip(
zipName,
destinationDirectory +
File.separatorChar +
zipName.substring(0,zipName.lastIndexOf(".zip"))
);
}
} catch (IOException e) {
e.printStackTrace();
return false ;
}
return true;
}
Hope this will help you.. Happy Coding :)
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.