JAVA学习笔记——高效缓冲区和数组方式拷贝文件效率实验
1 package IODemo; 2 3 import java.io.BufferedInputStream; 4 import java.io.BufferedOutputStream; 5 import java.io.FileInputStream; 6 import java.io.FileNotFoundException; 7 import java.io.FileOutputStream; 8 import java.io.IOException; 9 import java.io.InputStream; 10 import java.io.OutputStream; 11 12 public class CopyPic { 13 14 public static void main(String[] args) { 15 long start = System.currentTimeMillis(); 16 copyForBuffered(); 17 long end = System.currentTimeMillis(); 18 System.out.println((end-start)+"毫秒----缓冲区");//取出系统时间，相减后得出拷贝所用的时间 19 long start2 = System.currentTimeMillis(); 20 copyForChar(); 21 long end2 = System.currentTimeMillis(); 22 System.out.println((end2-start2)+"毫秒---数组"); 23 } 24 static void copyForChar(){ 25 // TODO Auto-generated method stub 26 InputStream read = null; 27 OutputStream write = null; 28 try { 29 read = new FileInputStream("C:/Users/Administrator/Desktop/IO/temp/伊瓜因进球1516进球记录.mp4"); 30 write = new FileOutputStream("C:/Users/Administrator/Desktop/IO/temp/伊瓜因copy2.mp4"); 31 byte[] saveBytes = new byte[1024]; 32 int numOfSave = 0; 33 while((numOfSave=read.read(saveBytes))!=-1){ 34 write.write(saveBytes, 0, numOfSave); 35 write.flush(); 36 } 37 } catch (FileNotFoundException e) { 38 // TODO Auto-generated catch block 39 e.printStackTrace(); 40 }catch(Exception e){ 41 e.printStackTrace(); 42 }finally{ 43 try{ 44 if(read!=null){ 45 read.close(); 46 } 47 if(write!=null){ 48 write.close(); 49 } 50 }catch(Exception e){ 51 e.printStackTrace(); 52 } 53 54 55 } 56 } 57 static void copyForBuffered() { 58 InputStream read=null; 59 OutputStream write =null; 60 BufferedInputStream Bread =null; 61 BufferedOutputStream Bwrite=null; 62 try { 63 read = new FileInputStream("C:/Users/Administrator/Desktop/IO/temp/伊瓜因进球1516进球记录.mp4"); 64 write = new FileOutputStream("C:/Users/Administrator/Desktop/IO/temp/伊瓜因BCOPY.mp4"); 65 Bread = new BufferedInputStream(read); 66 Bwrite = new BufferedOutputStream(write); 67 int saveNum = 0; 68 byte[] saveByte = new byte[1024]; 69 while((saveNum=Bread.read(saveByte))!=-1){ 70 Bwrite.write(saveByte,0,saveNum); 71 Bwrite.flush(); 72 } 73 74 } catch (FileNotFoundException e) { 75 // TODO Auto-generated catch block 76 e.printStackTrace(); 77 }catch(IOException e){ 78 e.printStackTrace(); 79 }finally{ 80 try{ 81 if(Bwrite!=null){ 82 Bwrite.close(); 83 } 84 if(Bread!=null){ 85 Bread.close(); 86 } 87 }catch(Exception e){ 88 e.printStackTrace(); 89 } 90 91 } 92 } 93 } 94
由此可以看出，拷贝高效缓冲区效率提升不少！
