import java.math.BigDecimal; import java.text.DecimalFormat; import java.text.NumberFormat; public class testNumber { public static double num = 3.1015926; public static double zero = 0.00000; //方法一:打印最简便,永远是末尾有两位小数 public static void function1(){ System.out.println(String.format("%.2f", num)); System.out.println(String.format("%.2f", zero)); } //方法二:转换后是String类型 public static void function2(){ DecimalFormat df = new DecimalFormat("0.00"); System.out.println(df.format(num)); System.out.println(df.format(zero)); } //方法三:转换后是double类型,但会省去最末位的0,只保留一位0 public static void function3(){ BigDecimal bg1 = new BigDecimal(num); double finalNum = bg1.setScale(2, BigDecimal.ROUND_HALF_UP).doubleValue(); System.out.println(finalNum); BigDecimal bg2 = new BigDecimal(zero); double finalZero = bg2.setScale(2, BigDecimal.ROUND_HALF_UP).doubleValue(); System.out.println(finalZero); } //方法四:末尾的0都会省去 3.1001->3.1,0.0000->0 public static void function4(){ NumberFormat nf = NumberFormat.getNumberInstance(); nf.setMaximumFractionDigits(2); System.out.println(nf.format(num)); System.out.println(nf.format(zero)); } public static void main(String args[]){ System.out.println("function1:"); function1(); System.out.println("function2:"); function2(); System.out.println("function3:"); function3(); System.out.println("function4:"); function4(); } }
结果展示:
时间: 2024-10-07 07:56:12