如何将图片，声音，影像等文件读入字节数组中

/**

  * 以字节为单位读取文件，常用于读二进制文件，如图片、声音、影像等文件。

  */

 publicstaticbyte[] readFileByBytes(String fileName) {

  InputStream in = null;

  ByteArrayOutputStream out = newByteArrayOutputStream();

  try{

   in = newFileInputStream(fileName);

   byte[] buf = newbyte[1024];

   intlength = 0;

   while((length = in.read(buf)) != -1) {

    out.write(buf,0, length);

   }

  }catch(Exception e1) {

   e1.printStackTrace();

  }finally{

   if(in != null) {

    try{

     in.close();

    }catch(IOException e1) {

    }

   }

  }

  returnout.toByteArray();

 }










1.  /** 
2.      * NIO way 
3.      * @param filename 
4.      * @return 
5.      * @throws IOException 
6.      */  
7.     public static byte[] toByteArray2(String filename)throws IOException{  
8.           
9.         File f = new File(filename);  
10.         if(!f.exists()){  
11.             throw new FileNotFoundException(filename);  
12.         }  
13.           
14.         FileChannel channel = null;  
15.         FileInputStream fs = null;  
16.         try{  
17.             fs = new FileInputStream(f);  
18.             channel = fs.getChannel();  
19.             ByteBuffer byteBuffer = ByteBuffer.allocate((int)channel.size());  
20.             while((channel.read(byteBuffer)) > 0){  
21.                 // do nothing  
22. //              System.out.println("reading");  
23.             }  
24.             return byteBuffer.array();  
25.         }catch (IOException e) {  
26.             e.printStackTrace();  
27.             throw e;  
28.         }finally{  
29.             try{  
30.                 channel.close();  
31.             }catch (IOException e) {  
32.                 e.printStackTrace();  
33.             }  
34.             try{  
35.                 fs.close();  
36.             }catch (IOException e) {  
37.                 e.printStackTrace();  
38.             }  
39.         }  
40.     }  
41.       
42.       
43.     /** 
44.      * Mapped File  way 
45.      * MappedByteBuffer 可以在处理大文件时，提升性能 
46.      * @param filename 
47.      * @return 
48.      * @throws IOException 
49.      */  
50.     public static byte[] toByteArray3(String filename)throws IOException{  
51.           
52.         FileChannel fc = null;  
53.         try{  
54.             fc = new RandomAccessFile(filename,"r").getChannel();  
55.             MappedByteBuffer byteBuffer = fc.map(MapMode.READ_ONLY, 0, fc.size()).load();  
56.             System.out.println(byteBuffer.isLoaded());  
57.             byte[] result = new byte[(int)fc.size()];  
58.             if (byteBuffer.remaining() > 0) {  
59. //              System.out.println("remain");  
60.                 byteBuffer.get(result, 0, byteBuffer.remaining());  
61.             }  
62.             return result;  
63.         }catch (IOException e) {  
64.             e.printStackTrace();  
65.             throw e;  
66.         }finally{  
67.             try{  
68.                 fc.close();  
69.             }catch (IOException e) {  
70.                 e.printStackTrace();  
71.             }  
72.         }  
73.     }  
74. }