public class MathUtil {
    
    public static void main(String[] args) {
        System.out.println(toPercent(1,3));
    }
    
    //a/b轉百分數字符串 (double)Math.round( a/(double)b*1000)/1000：保留3位小數四舍五入
    private static String toPercent(int a,int b) {
        return (double)Math.round( a/(double)b*1000)/10+"%";
    }
    
    
 
//Object轉整數（失敗返回null）
    private Integer toInt(Object o) {
        if (o!=null && !"".equals(o.toString())) {
            try {
                int parseInt = Integer.parseInt(o.toString());
                return parseInt;
            } catch (NumberFormatException e) {
                e.printStackTrace();
                
 
return null;
            }
        }
        return null;
    }
}

java 對象轉整數，兩個整數相除轉百分數