java DecimalFormat

public class Test{

public static void main(String[] args) throws Exception{

/*DecimalFormat参数，如果是0则会显示0，如果是#怎不显示0*/
DecimalFormat df = new DecimalFormat("0.00");
System.out.println(df.format(1231213));
//输出：1231213.00

DecimalFormat df_2 = new DecimalFormat("#.##");
System.out.println(df_2.format(1231213));
//输出：1231213

}

}

java.text.DecimalFormat API

Symbol Location Localized? Meaning

0 Number Yes Digit

# Number Yes Digit, zero shows as absent