how to get cell value from the hbase table via the key word?

[ventlam]

   hey,guy!
    I would like to get the cell value via the key word like"viki" . I used 
ValueFilter to implement it ,but i got nothing. Is there any other ideas?
  My code as follow:
try
                {
                           HTable htable = new 
HTable(hconf,Bytes.toBytes(tablename));
                         
                           ValueFilter vfilter = new 
ValueFilter(CompareOp.EQUAL,new BinaryComparator(Bytes.toBytes(value)));
                         
                           Scan s =new Scan();
                           s.setFilter(vfilter);
                           ResultScanner rscanner = htable.getScanner(s);
                        
                           for(Result rs : rscanner)
                           {
                                   byte [] by = 
rs.getValue(Bytes.toBytes(tablename));
                                        
                                        String vt= Bytes.toString(by);
                                         System.out.println("The value is "+ 
vt);
                           }
                           
                }
                catch(IOException e)
                {
                        e.printStackTrace();
                }