因為buffered多了一個緩沖區，讀和寫都是先把硬盤或者內存中的數據放到內存中一塊緩存區域，到一定大小讀寫到硬盤或者內存

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package io;

import java.io.*;

public class FileIOTest {

??? /**
???? * @param args
???? * @throws FileNotFoundException
???? */
??? public static void main(String[] args) throws Exception {

??????? //有buff的File***Stream
??????? System.out.println("有buff的File***Stream耗時：");
??????? new TimeTest() {
??????????? void run()throws Exception{
??????????????? FileInputStream fis = new FileInputStream("F:\\Test\\file.zip");

??????????????? FileOutputStream fos = new FileOutputStream("F:\\Test\\file1.zip");

??????????????? byte[] buf = new byte[1024];

??????????????? int length = 0;

??????????????? while ((length = fis.read(buf)) > 0) {
??????????????????? fos.write(buf, 0, length);
??????????????? }

??????????????? fis.close();
??????????????? fos.close();

??????????? }
??????? }.getTime();
???????
??????? //有buff的Buffered***Stream
??????? System.out.println("有buff的Buffered***Stream耗時：");
??????? new TimeTest() {
??????????? void run()throws Exception{

??????????????? BufferedInputStream bis = new BufferedInputStream(new FileInputStream("F:\\Test\\file.zip"));

??????????????? BufferedOutputStream bos = new BufferedOutputStream(
??????????????????????? new FileOutputStream("F:\\Test\\file2.zip"));
???????????????
??????????????? byte[] buf = new byte[1024];

??????????????? int length = 0;
???????????????
??????????????? while ((length = bis.read(buf)) > 0) {
??????????????????? bos.write(buf, 0, length);
??????????????? }

??????????????? bis.close();
??????????????? bos.close();
???????????????
??????????? }
??????? }.getTime();
???????
??????? //無buff的File***Stream
??????? System.out.println("無buff的File***Stream耗時：");
??????? new TimeTest() {
??????????? void run()throws Exception{
??????????????? FileInputStream fis = new FileInputStream("F:\\Test\\file.zip");

??????????????? FileOutputStream fos = new FileOutputStream("F:\\Test\\file3.zip");

??????????????? int data = 0;

??????????????? while ((data = fis.read()) !=-1) {
??????????????????? fos.write(data);
??????????????? }

??????????????? fis.close();
??????????????? fos.close();
??????????? }
??????? }.getTime();
???????
??????? //無buff的Buffered***Stream
??????? System.out.println("無buff的Buffered***Stream耗時：");
??????? new TimeTest() {
??????????? void run()throws Exception{
??????????????? BufferedInputStream bis = new BufferedInputStream(new FileInputStream("F:\\Test\\file.zip"));

??????????????? BufferedOutputStream bos = new BufferedOutputStream(
??????????????????????? new FileOutputStream("F:\\Test\\file4.zip"));
???????????????
??????????????? int data = 0;
???????????????
??????????????? int i =bis.available();
???????????????
??????????????? while ((data = bis.read()) !=-1) {
??????????????????? bos.write((byte)data);
??????????????? }

??????????????? bis.close();
??????????????? bos.close();
??????????? }
??????? }.getTime();
??? }

}

//抽象的不太好的模板設計模式
abstract class TimeTest {

??? void getTime() {
??????? long start = System.currentTimeMillis();
??????? try {
??????????? run();
??????? } catch (Exception e) {
??????????? // TODO Auto-generated catch block
??????????? e.printStackTrace();
??????? }
??????? System.out.println(System.currentTimeMillis() - start);
??? }

??? abstract void run() throws Exception;
}

?

?

測試數據248kb

?

測試結果：

?

有buff的File***Stream耗時：
8
有buff的Buffered***Stream耗時：
2
無buff的File***Stream耗時：
1369
無buff的Buffered***Stream耗時：
14

轉載于:https://www.cnblogs.com/flying607/p/3460389.html

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