一个基于JAVA的多torrent下载程序

				package org.bouncycastle.asn1;
				
				import java.io.IOException;
				
				/**
				 * A BER NULL object.
				 */
				public class BERNull
				    extends DERNull
				{
				    public BERNull()
				    {
				    }
				
				    void encode(
				        DEROutputStream  out)
				        throws IOException
				    {
				        if (out instanceof ASN1OutputStream || out instanceof BEROutputStream)
				        {
				            out.write(NULL);
				            out.write(0);
				            out.write(0);
				        }
				        else
				        {
				            super.encode(out);
				        }
				    }
				}