Question

Java如何高效合并多个文件

Answer 1

import static java.lang.System.out;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.util.Arrays;

public class test {
public static final int BUFSIZE = 1024 * 8;
public static void mergeFiles(String outFile, String[] files) {
FileChannel outChannel = null;
out.println("Merge " + Arrays.toString(files) + " into " + outFile);
try {
outChannel = new FileOutputStream(outFile).getChannel();
for(String f : files){
FileChannel fc = new FileInputStream(f).getChannel();
ByteBuffer bb = ByteBuffer.allocate(BUFSIZE);
while(fc.read(bb) != -1){
bb.flip();
outChannel.write(bb);
bb.clear();
}
fc.close();
}
out.println("Merged!! ");
} catch (IOException ioe) {
ioe.printStackTrace();
} finally {
try {if (outChannel != null) {outChannel.close();}} catch (IOException ignore) {}
}
}
public static void main(String[] args) {
mergeFiles("D:/output.txt", new String[]{"D:/in_1.txt", "D:/in_2.txt", "D:/in_3.txt"});
}
}