RandomAccessFile 里面应该没有定义缓冲区数组吧?  我在那个类里面没看到数组成员变量 如果有的话  如果一个文件足够大的话 全部存储在byte数组中会发生堆内存溢出啊   还有用该类时我不用数当缓冲区 复制一个大文件时慢的跟乌龟爬似的  还有我下面的代码为什么复制完文件以后 播放不了啊 ?  复制后的文件跟复制前的文件一样大的 啊

1. import java.io.File;
   
2. import java.io.FileNotFoundException;
   
3. import java.io.IOException;
   
4. import java.io.RandomAccessFile;
   
5. import java.util.Collections;
   
6. 
   
7. public class RandomAccessInputSreamDemo {
   
8. public static void main(String[] args) throws IOException {
   
9. String s=new String();
   
10. CopyFile cf1=new CopyFile(s);
    
11. CopyFile cf2=new CopyFile(s);
    
12. CopyFile cf3=new CopyFile(s);
    
13. CopyFile cf4=new CopyFile(s);
    
14. cf1.start();
    
15. cf2.start();
    
16. cf3.start();
    
17. cf4.start();
    
18. 
    
19. }
    
20. }
    
21. class CopyFile extends Thread{
    
22. private static int count =0;
    
23. private String lock;
    
24. public CopyFile(String lock){
    
25. this.lock=lock;
    
26. }
    
27. @Override
    
28. public void run(){
    
29. RandomAccessFile readRaf=null;
    
30. RandomAccessFile raf=null;
    
31. try {
    
32. readRaf=new RandomAccessFile("c:/张孝祥JAVA基础2_1.avi","r");
    
33. raf=new RandomAccessFile("d:/张孝祥JAVA基础2_1.avi","rw");
    
34. long fileLength=readRaf.length();
    
35. long tmpLen=fileLength/4;
    
36. long copyLength=0;
    
37. synchronized(lock){
    
38. copyLength=count==3?fileLength-1:(tmpLen+1)*count-1;
    
39. raf.seek(count*tmpLen);
    
40. readRaf.seek(count++*tmpLen);
    
41. }
    
42. int number=(int)(copyLength/(1024*1024*3));
    
43. int tmp=(int)(copyLength-number*(1024*1024*3));
    
44. byte buf[]=new byte[1024*1024*3];
    
45. while(readRaf.getFilePointer()<=copyLength){
    
46. if(number--==1){
    
47. buf=new byte[(1024*1024*3)+tmp];
    
48. }
    
49. int b=readRaf.read(buf);
    
50. raf.write(buf,0,b);
    
51. }
    
52. } catch (IOException e) {
    
53. e.printStackTrace();
    
54. }finally{
    
55. try {
    
56. readRaf.close();
    
57. raf.close();
    
58. } catch (IOException e) {
    
59. e.printStackTrace();
    
60. }
    
61. 
    
62. }
    
63. }
    
64. 
    
65. }

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