两段copy文件的代码

1.传统的基于IO的Copy方法

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

public class Snippet {
	public static void copyFile(File source, File dest) throws IOException {
		if (!dest.exists()) {
			dest.createNewFile();
		}
		InputStream in = null;
		OutputStream out = null;
		try {
			in = new FileInputStream(source);
			out = new FileOutputStream(dest);

			// Transfer bytes from in to out
			byte[] buf = new byte[1024];
			int len;
			while ((len = in.read(buf)) > 0) {
				out.write(buf, 0, len);
			}
		} finally {
			if (in != null) {
				in.close();
			}
			if (out != null) {
				out.close();
			}
		}
	}
}

2.基于NIO的高效的Copy方法

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

public class Snippet {

	public static void copyFile(File sourceFile, File destFile) throws IOException {
		if (!destFile.exists()) {
			destFile.createNewFile();
		}

		FileChannel source = null;
		FileChannel destination = null;
		try {
			source = new FileInputStream(sourceFile).getChannel();
			destination = new FileOutputStream(destFile).getChannel();
			destination.transferFrom(source, 0, source.size());
		} finally {
			if (source != null) {
				source.close();
			}
			if (destination != null) {
				destination.close();
			}
		}
	}
}