java实现两个文件的拼接

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;


public class Append 
{
  static int count=0;
  static int countb=0;

  public static void main(String args[]) throws IOException
  {
     FileInputStream filea = new FileInputStream("d:\\JavaXor\\a");
     FileInputStream fileb = new FileInputStream("d:\\JavaXor\\b");
     File outfile=new File("d:\\JavaXor\\outfile");
     int filesizea=filea.available();//计算文件的大小
     int filesizeb=fileb.available();
     FileOutputStream fos=new FileOutputStream(outfile);

     int hasReada = 0;
     int hasReadb=0;

     byte[] bufa=new byte[1024];
     byte[] bufc=new byte[1024];
     byte[] buf_yua=new byte[filesizea%1024];
     byte[] buf_yub=new byte[filesizeb%1024];

     while( (hasReada=filea.read(bufa) )>0 )
      {
      if(count<filesizea-filesizea%1024)
      {  
        for(int i=0;i<bufa.length && count<filesizea-filesizea%1024;i++)
         {

          bufc[i]=(byte)(bufa[i] & 0xFF);
          count++;

         }
        fos.write(bufc);
      }
      else if(count>=filesizea-filesizea%1024 && count<filesizea)
      {

        for(int j=0; count>=filesizea-filesizea%1024 && count<filesizea ;j++)
        {
          buf_yua[j]=(byte)(bufa[j] & 0xFF);
          count++;

        }
        fos.write(buf_yua);
      }

      }

     while( (hasReadb=fileb.read(bufa) )>0 )
      {
      if(countb<filesizeb-filesizeb%1024)
      {  
        for(int i=0;i<bufa.length && countb<filesizeb-filesizeb%1024;i++)
         {

          bufc[i]=(byte)(bufa[i] & 0xFF);
          countb++;

         }
        fos.write(bufc);
      }
      else if(countb>=filesizeb-filesizeb%1024 && countb<filesizeb)
      {

        for(int j=0; countb>=filesizeb-filesizeb%1024 && countb<filesizeb ;j++)
        {
          buf_yub[j]=(byte)(bufa[j] & 0xFF);
          countb++;

        }
        fos.write(buf_yub);
      }



      } 

  }


}