Java使用千分位并保留两位小数

double d = 123456.789;
DecimalFormat df = new DecimalFormat("#,##0.00");
System.out.println(df.format(d));

Math.formatFloat = function (f, digit) {
var m = Math.pow(10, digit);
return parseInt(f * m, 10) / m;
};

function formatThousand(num) {
num = num + "";
var re = /(-?\d+)(\d{3})/;
while (re.test(num)) {
num = num.replace(re, "$1,$2");
}
return num;
}