保留两位小数

public static void main(String[] args) {  
       String str="86.64466666";  
       BigDecimal bd = new BigDecimal(Double.parseDouble(str));  
       System.out.println(bd.setScale(2, BigDecimal.ROUND_HALF_UP).doubleValue());  
       System.out.println("=================");  
         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)));   
   }