拷貝

• 元資料——>目的地

拷貝方式：

• 單個 位元組/字元 的拷貝
• 按照 位元組/字元 陣列拷貝

測試

• 單個位元組和位元組陣列讀取時間
• 非緩衝與帶緩衝的讀取時間

package com.bigdat.java.day25;
import java.io.*;
/*
    測試
        單個位元組和位元組陣列讀取時間
        非緩衝與帶緩衝的讀取時間
 */
public class CopyDemo2 {
    public static void main(String[] args) {
          // oneTest();  單個位元組讀取視屏的時間為2107904毫秒
         // shuZuTest(); 陣列讀取視屏的時間為2392毫秒
        //  OneBufferText();  緩衝單位元組讀取視屏的時間為：9503毫秒
        // shuzuBufferText(); 緩衝位元組陣列讀取視屏的時間為：547毫秒
    }
    //測試單個字元讀取一段視屏的時間
    public static void oneTest(){
        //建立讀取物件
        FileInputStream fileInputStream = null;
        //建立寫出物件
        FileOutputStream fileOutputStream = null;

        try {
            fileInputStream = new FileInputStream("D:\\我被改名了\\17day24 位元組流速度對比，編碼表 2.mp4");
            fileOutputStream = new FileOutputStream("D:\\我被改名了\\copy1.mp4");
            Long start = System.currentTimeMillis();
            //開始讀取
            int len = 0;
            while((len = fileInputStream.read()) != -1){
                fileOutputStream.write(len);
            }
            long end = System.currentTimeMillis();
            System.out.println("單個位元組讀取視屏的時間為"+(end-start)+"毫秒");

        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            try {
                fileOutputStream.close();
                fileInputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }


    }
    //測試位元組陣列copy視屏的時間
    public static void shuZuTest(){
        //建立讀取物件
        FileInputStream fileInputStream = null;
        //建立寫出物件
        FileOutputStream fileOutputStream = null;

        try {
            fileInputStream = new FileInputStream("D:\\我被改名了\\17day24 位元組流速度對比，編碼表 2.mp4");
            fileOutputStream = new FileOutputStream("D:\\我被改名了\\copy2.mp4");
            Long start = System.currentTimeMillis();
            //開始讀取
            int len = 0;
            byte[] bytes = new byte[1024];
            while((len = fileInputStream.read(bytes)) != -1){
                fileOutputStream.write(bytes, 0, len);
            }
            long end = System.currentTimeMillis();
            System.out.println("陣列讀取視屏的時間為"+(end-start)+"毫秒");

        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            try {
                fileOutputStream.close();
                fileInputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

    }
      //緩衝流單個位元組讀取視屏測試時間
    public static void OneBufferText(){
        //建立讀入位元組的物件
        BufferedInputStream bufferedInputStream = null;
        BufferedOutputStream bufferedOutputStream = null;

        try {
            bufferedInputStream = new BufferedInputStream(new FileInputStream("D:\\我被改名了\\17day24 位元組流速度對比，編碼表 2.mp4"));
            bufferedOutputStream = new BufferedOutputStream(new FileOutputStream("D:\\我被改名了\\copy3.mp4"));

            //開始時間
            long start = System.currentTimeMillis();
            //開始寫入到程式中
            int len = 0;
            while((len = bufferedInputStream.read()) != -1){
                bufferedOutputStream.write(len);
            }
            long end = System.currentTimeMillis();
            System.out.println("緩衝單位元組讀取視屏的時間為："+(end-start));


        } catch (IOException e) {
            e.printStackTrace();
        }
        finally {
            try {
                bufferedOutputStream.close();
                bufferedInputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }


    }
    public static void shuzuBufferText(){
        //建立讀入位元組的物件
        BufferedInputStream bufferedInputStream = null;
        BufferedOutputStream bufferedOutputStream = null;

        try {
            bufferedInputStream = new BufferedInputStream(new FileInputStream("D:\\我被改名了\\17day24 位元組流速度對比，編碼表 2.mp4"));
            bufferedOutputStream = new BufferedOutputStream(new FileOutputStream("D:\\我被改名了\\copy4.mp4"));

            //開始時間
            long start = System.currentTimeMillis();
            //開始寫入到程式中
            int len = 0;
            byte[] bytes = new byte[1024];
            while((len = bufferedInputStream.read(bytes)) != -1){
                bufferedOutputStream.write(bytes, 0, len);
            }
            long end = System.currentTimeMillis();
            System.out.println("緩衝位元組陣列讀取視屏的時間為："+(end-start)+"毫秒");


        } catch (IOException e) {
            e.printStackTrace();
        }
        finally {
            try {
                bufferedOutputStream.close();
                bufferedInputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }



    }
}
 

package com.bigdat.java.day25;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
/*
   將 D盤中的p.txt 檔案拷貝一份到 D 盤中的 q.txt 檔案
 */
public class CopyDemo1 {
    public static void main(String[] args) {
        FileInputStream fileInputStream = null;
        FileOutputStream fileOutputStream = null;
        try {
            //建立檔案輸入流
             fileInputStream = new FileInputStream("D:\\p.txt");
            //建立檔案的輸出流
             fileOutputStream = new FileOutputStream("D:\\w.txt");

             //開始讀取檔案
            //方法一：一個位元組一個位元組的讀
//            int len = 0;
//            while ((len = fileInputStream.read()) !=-1){
//                fileOutputStream.write(len);
//            }
            //方式二：利用位元組陣列讀取
            byte[] bytes = new byte[1024];
            int len = 0;
            while ((len = fileInputStream.read(bytes)) != -1){
                System.out.println(len);
                fileOutputStream.write(bytes, 0, len);
            }
            System.out.println("複製成功！");
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            try {
                fileOutputStream.close();
                fileInputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

    }
}