java保留两位小数4种方法

 1     import java.math.BigDecimal; 2     import java.text.DecimalFormat; 3     import java.text.NumberFormat; 4     public class format { 5         double f = 111231.5585; 6         public void m1() { 7             BigDecimal bg = new BigDecimal(f); 8             double f1 = bg.setScale(2, BigDecimal.ROUND_HALF_UP).doubleValue(); 9             System.out.println(f1);10         }11         /**12          * DecimalFormat转换最简便13          */14         public void m2() {15             DecimalFormat df = new DecimalFormat("#.00");16             System.out.println(df.format(f));17         }18         /**19          * String.format打印最简便20          */21         public void m3() {22             System.out.println(String.format("%.2f", f));23         }24         public void m4() {25             NumberFormat nf = NumberFormat.getNumberInstance();26             nf.setMaximumFractionDigits(2);27             System.out.println(nf.format(f));28         }29         public static void main(String[] args) {30             format f = new format();31             f.m1();32             f.m2();33             f.m3();34             f.m4();35         }36     }