public void close(){
		try{
			
			if(prst != null){
				prst.close();
				prst = null;
			}
			
			
			if(connectioncon != null){
				connectioncon.close();
				connectioncon = null;
			}
			
			if(rese != null){
				rese.close();
				rese = null;
			}
			
		}
		catch(Exception ex){
			System.err.println("close error :"+ex.getMessage());
		}
	}