数字、时间等单位换算工具类收集

1. 将字节数转换成KB或者MB

public static String bytes2kb(long bytes) {        BigDecimal filesize = new BigDecimal(bytes);        BigDecimal megabyte = new BigDecimal(1024 * 1024);        float returnValue = filesize.divide(megabyte, 2, BigDecimal.ROUND_UP)                .floatValue();        if (returnValue > 1)            return (returnValue + "MB");        BigDecimal kilobyte = new BigDecimal(1024);        returnValue = filesize.divide(kilobyte, 2, BigDecimal.ROUND_UP)                .floatValue();        return (returnValue + "KB");    }