生成随机出生日期

random java

2022-08-31 14:03:57

我正在尝试使用Java程序为数据库中的人生成随机的出生日期。我该怎么做？

答案 1

import java.util.GregorianCalendar;

public class RandomDateOfBirth {

    public static void main(String[] args) {

        GregorianCalendar gc = new GregorianCalendar();

        int year = randBetween(1900, 2010);

        gc.set(gc.YEAR, year);

        int dayOfYear = randBetween(1, gc.getActualMaximum(gc.DAY_OF_YEAR));

        gc.set(gc.DAY_OF_YEAR, dayOfYear);

        System.out.println(gc.get(gc.YEAR) + "-" + (gc.get(gc.MONTH) + 1) + "-" + gc.get(gc.DAY_OF_MONTH));

    }

    public static int randBetween(int start, int end) {
        return start + (int)Math.round(Math.random() * (end - start));
    }
}

答案 2

java.util.Date具有一个自 The Epoch 以来接受毫秒的构造函数，并且具有一个可以为您提供随机毫秒数的方法。您需要根据所需的 DOB 范围为随机值设置一个范围，但这些应该这样做。java.util.Random

非常粗略地：

Random  rnd;
Date    dt;
long    ms;

// Get a new random instance, seeded from the clock
rnd = new Random();

// Get an Epoch value roughly between 1940 and 2010
// -946771200000L = January 1, 1940
// Add up to 70 years to it (using modulus on the next long)
ms = -946771200000L + (Math.abs(rnd.nextLong()) % (70L * 365 * 24 * 60 * 60 * 1000));

// Construct a date
dt = new Date(ms);