IO文件复制

 

使用两种方式复制1.2G文件差异不大，缓冲区设置影响也不大。

ioCopyFile		newIoCopyFile
缓冲区	时间	缓冲区	时间
1024	49774	1024	36653
2048	42632	2048	35792
4096	41671	4096	32142
8192	34022	8192	38983
16384	36983	16384	36000

   

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;

public class CopyFileTest {
    public static void main(String[] args) throws IOException {
        new CopyFileTest().ioCopyFile("X:\\archive.zip", "X:\\archive2.zip");
        new CopyFileTest().newIoCopyFile("X:\\archive.zip", "X:\\archive2.zip");
    }

    public void newIoCopyFile(String sourcePath, String destPath) throws IOException {
        FileInputStream fi = new FileInputStream(sourcePath);
        FileOutputStream fo = new FileOutputStream(destPath);

        FileChannel inChannel = fi.getChannel();
        FileChannel outChannel = fo.getChannel();

        ByteBuffer buffer = ByteBuffer.allocate(16384);
        while (true) {
            buffer.clear();
            int r = inChannel.read(buffer);
            if (r == -1) {
                break;
            }
            buffer.flip();
            outChannel.write(buffer);
        }
    }

    public void ioCopyFile(String sourcePath, String destPath) throws IOException {
        FileInputStream fi = new FileInputStream(sourcePath);
        FileOutputStream fo = new FileOutputStream(destPath);
        byte b[] = new byte[16384];
        while (fi.read(b) != -1) {
            fo.write(b);
        }
        fi.close();
        fo.close();

    }
}