使用拷贝文件测试（BufferedInputStream，FileInputStream）

Posted 2021-01-06 tc310

package com.demo;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

public class CopyFileDemo {

    public static void main(String[] args) {
        
        long beginTime = System.currentTimeMillis();
        copyFileBuffer();
        long endTime = System.currentTimeMillis();
        System.out.println("Buffered拷贝所花的时间："+(endTime-beginTime)+"毫秒");
         
        long beginTime1 = System.currentTimeMillis();
        copyFile();
        long endTime1 = System.currentTimeMillis();
        System.out.println("FileIn/Out拷贝所花的时间："+(endTime1-beginTime1)+"毫秒");
    }
     
    public static void copyFileBuffer(){
//        File file=  new File("G:/MP4视频");
//        file.mkdir();
        try {
            BufferedInputStream bin = new BufferedInputStream(new FileInputStream("G:/install/ISO/XLJS_GHOST_XP_SP3_FT_2.0.iso"));
            BufferedOutputStream bout = new BufferedOutputStream(new FileOutputStream("H:/TEST/1.iso"));         
            byte[] bt = new byte[8192];
            int n=0;
            while ((n=bin.read(bt))!=-1) {
                bout.write(bt, 0, n);     
                
            }
            bout.flush();
            bin.close();
            bout.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    public static void copyFile(){
        try {
            FileInputStream fin = new FileInputStream("G:/install/ISO/XLJS_GHOST_XP_SP3_FT_2.0.iso");
            FileOutputStream  fout=new FileOutputStream("H:/TEST/2.iso");
             
            byte[]  by = new byte[8192];
            int len = 0;
            while ((len=fin.read(by))!=-1) {
                fout.write(by, 0, len);
                
            }
            fout.flush();
            fout.close();
            fin.close();
             
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
         
    }

}

测试结果：文件大小：700M，用Buffered拷贝有时候反而比不用缓存拷贝还慢

有时候还是使用缓存快点，但是不是特别明显