java第四次作业

通过数组优化运算

import java.io.FileInputStream; 
import java.io.FileOutputStream;
import java.io.IOException;
public class CopyFile {
    public static void main(String[] args) {
        // TODO Auto-generated method stub
         CopyMp3 cy = new CopyMp3();
         cy.copy();
    }
     
}
class CopyMp3{
    public CopyMp3(){}
    void  copy(){
        long starttime = System.currentTimeMillis();
        try {
            FileInputStream fis = new FileInputStream("src/a.mp3");
            FileOutputStream fos = new FileOutputStream("src/temp.mp3");
            byte[] b = new byte[2048];
            int read = fis.read(b);
            while(read!=-1){
                fos.write(b);
                read = fis.read(b);
            }
            fis.close();
            fos.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        long endtime = System.currentTimeMillis();
        System.out.println("用时:"+(endtime-starttime)+"ms");
     
    }
}

运行结果：

优化前：

 

优化后：