java保留两位小数

1. double f = 111231.5585;
2. public void m1() {
3. BigDecimal bg = new BigDecimal(f);
4. double f1 = bg.setScale(2, BigDecimal.ROUND_HALF_UP).doubleValue();
5. System.out.println(f1);
6. }
7. /**
8. * DecimalFormat转换最简便
9. */
10. public void m2() {
11. DecimalFormat df = new DecimalFormat("#.00");
12. System.out.println(df.format(f));
13. }
14. /**
15. * String.format打印最简便
16. */
17. public void m3() {
18. System.out.println(String.format("%.2f", f));
19. }
20. public void m4() {
21. NumberFormat nf = NumberFormat.getNumberInstance();
22. nf.setMaximumFractionDigits(2);
23. System.out.println(nf.format(f));
24. }