import java.text.NumberFormat;

public class test {
    
    public static void main(String[] args) {
         double d =12345.00000000225168d;
         String s=formatDouble(d);
         System.out.println(s);
    }
     private static String formatDouble(double d) {
            NumberFormat nf = NumberFormat.getInstance();
            //设置保留多少位小数
            nf.setMaximumFractionDigits(20);
             // 取消科学计数法
            nf.setGroupingUsed(false);
            //返回结果
            return nf.format(d);
        }
}