Divide & Combine File -- SequenceInputStream

java.lang.Object
  java.io.InputStream
      java.io.SequenceInputStream

Example of divide a file:

      filepath: the file to be separated.
      size:the size of each separated file.
      count: the number of separated file.

FileInputStream fileInputStream = new FileInputStream(new File(filepath)); 
BufferedInputStream bufInputStream = new BufferedInputStream(fileInputStream); 
byte[] data = new byte[1]; 
int count = 0;  
//Count the number of separated files.
if(fileInputStream.available() % size == 0) 
      count = fileInputStream.available() / size; 
else 
      count = fileInputStream.available() / size + 1; 
for(int i = 0; i < count; i++) { 
      int num = 0; 
      File file = new File(filepath + "_" + (i + 1));
      BufferedOutputStream bufOutputStream = new BufferedOutputStream( 
                       new FileOutputStream(file)); 
      //Write the read-out data into a separated file
      while(bufInputStream.read(data) != -1) { 
             bufOutputStream.write(data);
             //count the bytes of the separated file.
             num++; 
             if(num == size) { 
                  bufOutputStream.flush(); 
                  bufOutputStream.close(); 
                  break; 
             } 
     } 
 
     if(num < size) { 
            bufOutputStream.flush(); 
            bufOutputStream.close(); 
     } 
} 
Example of combine separated files:
      filename: the path of  the separated files locate   
      number  : the number of the separated files.
List<InputStream> list = new ArrayList<InputStream>();
//collect the separated files
for(int i = 0; i < number; i++) {
       File file = new File(filename + "_" + (i+1));
       list.add(i, new FileInputStream(file));
}
final Iterator<InputStream> iterator = list.iterator();
Enumeration<InputStream> enumation = new Enumeration<InputStream>() {
                public boolean hasMoreElements() {
                    return iterator.hasNext();
                }

                public InputStream nextElement() {
                    return iterator.next();
                }
            };
BufferedInputStream bufInputStream = new BufferedInputStream( 
                    new SequenceInputStream(enumation), 
                    8192); 
BufferedOutputStream bufOutputStream = new BufferedOutputStream( 
                       new FileOutputStream(filename), 8192); 
byte[] data = new byte[1]; 

while(bufInputStream.read(data) != -1) 
        bufOutputStream.write(data); 
bufInputStream.close(); 
bufOutputStream.flush(); 
bufOutputStream.close();