java標准百分比

　　

import java.text.NumberFormat;

public class 百分比 {
   public static void main(String[] args) {
      int completed=30;
      int total=541;
      double percentage=((double) completed/(double) total)*100;
      NumberFormat numberFormat=NumberFormat.getPercentInstance();
      numberFormat.setMinimumFractionDigits(2);
      String result=numberFormat.format(((double)completed)/((double)total));
      System.out.println(result);
   }
}