Java speeds up reading and copying large files
- 2021-07-24 10:59:05
- OfStack
File channel (FileChannel) to achieve file replication, for your reference, the specific contents are as follows
Regardless of multithreaded optimization, the fastest method for single-threaded file copy is (the larger the file, the more advantageous this method is, which is generally 30 +% faster than common methods):
Directly on the code:
package test;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.channels.FileChannel;
public class Test {
public static void main(String[] args) {
File source = new File("E:\\tools\\fmw_12.1.3.0.0_wls.jar");
File target = new File("E:\\tools\\fmw_12.1.3.0.0_wls-copy.jar");
long start, end;
start = System.currentTimeMillis();
fileChannelCopy(source, target);
end = System.currentTimeMillis();
System.out.println(" File channel time: " + (end - start) + " Milliseconds ");
start = System.currentTimeMillis();
copy(source, target);
end = System.currentTimeMillis();
System.out.println(" Ordinary buffer time: " + (end - start) + " Milliseconds ");
}
/**
* Copy files using file channels
* @param source Source file
* @param target Object file
*/
public static void fileChannelCopy(File source, File target) {
FileInputStream in = null;
FileOutputStream out = null;
FileChannel inChannel = null;
FileChannel outChannel = null;
try {
in = new FileInputStream(source);
out = new FileOutputStream(target);
inChannel = in.getChannel();// Get the corresponding file channel
outChannel = out.getChannel();// Get the corresponding file channel
inChannel.transferTo(0, inChannel.size(), outChannel);// Connect the two channels and derive from the inChannel Channel read and then write to outChannel Channel
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
in.close();
inChannel.close();
out.close();
outChannel.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
/**
* Normal buffer replication
* @param source Source file
* @param target Object file
*/
public static void copy (File source, File target) {
InputStream in = null;
BufferedOutputStream out = null;
try {
in = new BufferedInputStream(new FileInputStream(source));
out = new BufferedOutputStream(new FileOutputStream(target));
byte[] buf = new byte[4096];
int i;
while ((i = in.read(buf)) != -1) {
out.write(buf, 0, i);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
if (null != in) {
in.close();
}
if (null != out) {
out.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}