DecimalFormat df=(DecimalFormat) DecimalFormat.getInstance();
df.applyPattern("0.00");//保留小数后几位
System.out.println(df.format(12));
System.out.println(df.format(12.1));
System.out.println(df.format(12.2222222));
DecimalFormat df=(DecimalFormat) DecimalFormat.getInstance();
df.applyPattern("0.00");//保留小数后几位
System.out.println(df.format(12));
System.out.println(df.format(12.1));
System.out.println(df.format(12.2222222));