Java Nio初探及普通io性能比较


package com.justsy.nio;

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

/**
 * @author zhangh
 * @createTime 2012-11-26 下午4:44:49
 */
public class NIOTest {
	public static void main(String[] args) throws Exception {
		NIOTest nioTest = new NIOTest();
		// 124MB for Test
		nioTest.nioCopy(); // 893ms
		nioTest.commonCopy() ; //1438ms
	}

	public void commonCopy() throws Exception {
		long current = System.currentTimeMillis();
		String file = "workspace.zip";
		File f = new File("D:\\" + file);
		int tmp = 0;
		FileInputStream in = new FileInputStream(f);
		FileOutputStream fos = new FileOutputStream(new File("D:\\New-" + file));

		byte[] buffer = new byte[512];

		while ((tmp = in.read(buffer)) != -1) {
			fos.write(buffer, 0, tmp);
		}

		fos.close();
		in.close();
		System.out.println("use millis : "
				+ (System.currentTimeMillis() - current));
	}

	public void nioCopy() throws Exception {
		long current = System.currentTimeMillis();
		String file = "workspace.zip";
		File f = new File("D:\\" + file);
		FileInputStream inputStream = new FileInputStream(f);
		FileChannel inChannel = inputStream.getChannel();
		FileOutputStream outputStream = new FileOutputStream(new File(
				"D:\\New-" + file));
		FileChannel outChannel = outputStream.getChannel();
		ByteBuffer b = ByteBuffer.allocate(1024);
		while (inChannel.read(b) != -1) {
			b.flip();
			outChannel.write(b);
			b.clear();
		}
		System.out.println("write success!!");
		outputStream.close();
		inputStream.close();
		System.out.println("use millis : "
				+ (System.currentTimeMillis() - current));
	}
}



http://www.cnblogs.com/focusj/archive/2011/11/03/2231583.html

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