01.import java.math.BigDecimal;02.import java.text.DecimalFormat;03.import java.text.NumberFormat;04.05.public class format {06.    double f = 111231.5585;07.    public void m1() {08.        BigDecimal bg = new BigDecimal(f);09.        double f1 = bg.setScale(2, BigDecimal.ROUND_HALF_UP).doubleValue();10.        System.out.println(f1);11.    }12.    /**13.     * DecimalFormat转换最简便14.     */15.    public void m2() {16.        DecimalFormat df = new DecimalFormat("#.00");17.        System.out.println(df.format(f));18.    }19.    /**20.     * String.format打印最简便21.     */22.    public void m3() {23.        System.out.println(String.format("%.2f", f));24.    }25.    public void m4() {26.        NumberFormat nf = NumberFormat.getNumberInstance();27.        nf.setMaximumFractionDigits(2);28.        System.out.println(nf.format(f));29.    }30.    public static void main(String[] args) {31.        format f = new format();32.        f.m1();33.        f.m2();34.        f.m3();35.        f.m4();36.    }37.}

结果：

111231.56

111231.56

111231.56

111,231.56

转自：