Question

我有这个方法，它返回一个由其中一个＆＃34;字段＆＃34;更改的Date（）。（每年，每年）。

public static Date getDateChanged(Date date, int field, int value) {
    Calendar cal = Calendar.getInstance();
    cal.setTime(date);
    cal.set(field, value);
    return cal.getTime();
}

但是，当我们尝试设置的字段与相关日期不兼容时，cal.set（）无法给出异常。所以，在这种情况下：

Date date = new Date();
date = getDateChanged(date, Calendar.DAY_OF_MONTH, 29); 
date = getDateChanged(date, Calendar.MONTH, 1); // feb

日期最后是2015年3月1日，因为Calendar.set（）检测到2月不能设置为第29天，因此自动将日期设置为下一个可能的日期（我认为这是常规的工作方式）。

然而，就我而言，这并不是那么糟糕，

我想检测到我尝试构建的日期是不可能的，然后开始递减当天，所以在这种情况下，我想要实现的是28/02/15， 我该怎么做？

示例：

29/02/15 ===＆gt; 28/02/15

Answer 1

您可以使用cal.getActualMaximum(Calendar.DAY_OF_MONTH)查找日历实例的给定月份的最长天数。

这样，您可以自己处理上面提到的案例。

另见答案：Number of days in particular month of particular year?

Answer 2

您可以使用：

public void setLenient(boolean lenient)

指定日期/时间解释是否宽松。通过宽松的解释，例如＆＃34; 1996年2月942和＃34;将被视为相当于2月1日后的第941天，通过严格（非宽大）的解释，这样的日期将导致抛出异常。默认值为lenient。

Parameters:
    lenient - true if the lenient mode is to be turned on; false if it is to be turned off.
See Also:
    isLenient(), DateFormat.setLenient(boolean)

这样，当你传递错误时会出现异常：）

Answer 3

您可以使用getActualMaximum检查最大值：

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Answer 4

可能这个解决方案会帮助你

public static Date getDateChanged(Date date, int field, int value) {
    Calendar cal = Calendar.getInstance();
    cal.setTime(date);
    cal.set(field, value);
    if (field == Calendar.MONTH && cal.get(Calendar.MONTH) != value) {
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        int month = (cal.get(Calendar.MONTH) - 1) < 0 ? 0 : (cal.get(Calendar.MONTH) - 1);
        calendar.set(Calendar.DATE, calendar.getActualMinimum(Calendar.DATE));
        calendar.set(Calendar.MONTH, month);
        calendar.set(Calendar.DATE, calendar.getActualMaximum(Calendar.DATE));
        return calendar.getTime();
    }
    return cal.getTime();
}

检测Calendar.set（）上的无效日期

4 个答案: