直接上代码：

public static void main(String[] args) {
        double db1 = 87406.70;
        double db2 = 778.93;
        double result = db1 + db2;
        System.out.println(result);
        BigDecimal b = new BigDecimal(result);
        result = b.setScale(2, BigDecimal.ROUND_HALF_UP).doubleValue();
        System.out.println(result);
    }