import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.IntBuffer;
import java.nio.channels.FileChannel;


public class compareMappedAndStream {

	private static int numOfInts = 4000000;
	private static int numOfUbuffInts = 2000000;

	private abstract static class Tester {
		private String name;

		public Tester(String name) {
			this.name = name;
		}

		public void runTest() {
			System.out.print(name + ": ");
			try {
				long start = System.nanoTime();//
				test();
				double duration = System.nanoTime() - start;
				System.out.format("%.2f\n", duration / 1.0e9);
			} catch (IOException e) {
				throw new RuntimeException(e);
			}
		}

		public abstract void test() throws IOException;
	}

	/**
	 * 测试各种流的效率
	 */
	private static Tester[] tests = {
	/**
	 * 测试Stream写的效率
	 */
	new Tester("Stream Write") {
		@Override
		public void test() throws IOException {
			DataOutputStream dos = new DataOutputStream(
					new BufferedOutputStream(new FileOutputStream(new File(
							"temp.tmp"))));
			for (int i = 0; i < numOfInts; i++) {
				dos.writeInt(i);
			}
			dos.close();
		}
	},
	/**
	 * 测试内存映射写的效率
	 */
	new Tester("Mapped Write") {
		@Override
		public void test() throws IOException {
			FileChannel fc = new RandomAccessFile("temp.tmp", "rw")
					.getChannel();
			IntBuffer ib = fc.map(FileChannel.MapMode.READ_WRITE, 0, fc.size())
					.asIntBuffer();
			for (int i = 0; i < numOfInts; i++) {
				ib.put(i);
			}
			fc.close();
		}
	},
	/**
	 * 测试Steam读的效率
	 */
	new Tester("Stream Read") {
		@Override
		public void test() throws IOException {
			DataInputStream dis = new DataInputStream(new BufferedInputStream(
					new FileInputStream("temp.tmp")));
			for (int i = 0; i < numOfInts; i++) {
				dis.readInt();
			}
			dis.close();
		}
	}, 
	/**
	 * 测试Mapped读的效率
	 */
	new Tester("Mapped Read") {
		@Override
		public void test() throws IOException {
			FileChannel fc = new FileInputStream(new File("temp.tmp")).getChannel();
			IntBuffer ib = fc.map(FileChannel.MapMode.READ_ONLY,0,fc.size()).asIntBuffer();
			while(ib.hasRemaining()){
				ib.get();
			}
			fc.close();
		}

	},
	new Tester("Stream Read/Write"){

		@Override
		public void test() throws IOException {
			RandomAccessFile raf = new RandomAccessFile(new File("temp.tmp"), "rw");
			raf.writeInt(1);
			for(int i = 0 ; i < numOfUbuffInts ; i ++){
				raf.seek(raf.length() - 4);
				raf.writeInt(raf.readInt());
			}
			raf.close();
		}},
	new Tester("Mapped Read/Write"){
		@Override
		public void test() throws IOException {
			FileChannel fc = new RandomAccessFile("temp.tmp", "rw").getChannel();
			IntBuffer ib = fc.map(FileChannel.MapMode.READ_WRITE,0,fc.size()).asIntBuffer();
			ib.put(0);
			for(int i = 1 ; i < numOfUbuffInts ; i ++){
				ib.put(ib.get(i -1));
			}
			fc.close();
		}
			
		}

	};
	/**
	 * 测试
	 * @param args
	 */
	public static void main(String[] args) {
		for(Tester tester : tests){
			tester.runTest();
		}
	}
}
运行结果：
Stream Write: 0.46
Mapped Write: 0.04
Stream Read: 0.46
Mapped Read: 0.04
Stream Read/Write: 43.14
Mapped Read/Write: 0.04