BigDecimal bd = new BigDecimal(0.0199999999999);  System.out.println("res:"+bd.setScale(2, BigDecimal.ROUND_HALF_UP).doubleValue());

 

 

DecimalFormat df = new DecimalFormat("#.00");            System.out.println(df.format(Double.parseDouble(str)));            System.out.println("=================");           System.out.println(String.format("%.2f", Double.parseDouble(str)));           System.out.println("=================");           NumberFormat nf = NumberFormat.getNumberInstance();            nf.setMaximumFractionDigits(2);            System.out.println(nf.format(Double.parseDouble(str)));