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在java/jsp里怎样判断一个yyyymmdd格式的字符串是合法的日期型字符串,并求两日期字符串之间的天数?
来源: 互联网 发布时间:2015-06-17
本文导语: 用户输入了yyyymmdd格式的字符串,怎样判断它是合法的日期,如20020500就非法; 给出合法的两个日期型yyyymmdd字符串,怎样求出之间的天数?如 20020501 -- 20020502是两天 ?? | 使用SimpleDateForma...
用户输入了yyyymmdd格式的字符串,怎样判断它是合法的日期,如20020500就非法;
给出合法的两个日期型yyyymmdd字符串,怎样求出之间的天数?如 20020501 -- 20020502是两天 ??
给出合法的两个日期型yyyymmdd字符串,怎样求出之间的天数?如 20020501 -- 20020502是两天 ??
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使用SimpleDateFormat,规定好格式,parser出错即为非法
/**
* Calculates the number of days between two calendar days in a manner
* which is independent of the Calendar type used.
*
* @param d1 The first date.
* @param d2 The second date.
*
* @return The number of days between the two dates. Zero is
* returned if the dates are the same, one if the dates are
* adjacent, etc. The order of the dates
* does not matter, the value returned is always >= 0.
* If Calendar types of d1 and d2
* are different, the result may not be accurate.
*/
static int getDaysBetween (java.util.Calendar d1, java.util.Calendar d2) {
if (d1.after(d2)) { // swap dates so that d1 is start and d2 is end
java.util.Calendar swap = d1;
d1 = d2;
d2 = swap;
}
int days = d2.get(java.util.Calendar.DAY_OF_YEAR) -
d1.get(java.util.Calendar.DAY_OF_YEAR);
int y2 = d2.get(java.util.Calendar.YEAR);
if (d1.get(java.util.Calendar.YEAR) != y2) {
d1 = (java.util.Calendar) d1.clone();
do {
days += d1.getActualMaximum(java.util.Calendar.DAY_OF_YEAR);
d1.add(java.util.Calendar.YEAR, 1);
} while (d1.get(java.util.Calendar.YEAR) != y2);
}
return days;
} // getDaysBetween()
/**
* Calculates the number of days between two calendar days in a manner
* which is independent of the Calendar type used.
*
* @param d1 The first date.
* @param d2 The second date.
*
* @return The number of days between the two dates. Zero is
* returned if the dates are the same, one if the dates are
* adjacent, etc. The order of the dates
* does not matter, the value returned is always >= 0.
* If Calendar types of d1 and d2
* are different, the result may not be accurate.
*/
static int getDaysBetween (java.util.Calendar d1, java.util.Calendar d2) {
if (d1.after(d2)) { // swap dates so that d1 is start and d2 is end
java.util.Calendar swap = d1;
d1 = d2;
d2 = swap;
}
int days = d2.get(java.util.Calendar.DAY_OF_YEAR) -
d1.get(java.util.Calendar.DAY_OF_YEAR);
int y2 = d2.get(java.util.Calendar.YEAR);
if (d1.get(java.util.Calendar.YEAR) != y2) {
d1 = (java.util.Calendar) d1.clone();
do {
days += d1.getActualMaximum(java.util.Calendar.DAY_OF_YEAR);
d1.add(java.util.Calendar.YEAR, 1);
} while (d1.get(java.util.Calendar.YEAR) != y2);
}
return days;
} // getDaysBetween()
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public static boolean ValidDateStr(String rStr, String rDateFormat) {
SimpleDateFormat formatter = new SimpleDateFormat (rDateFormat);
formatter.setLenient(false);
try {
formatter.format(formatter.parse(rStr));
} catch (Exception e) {
return false;
}
return true;
}
SimpleDateFormat formatter = new SimpleDateFormat (rDateFormat);
formatter.setLenient(false);
try {
formatter.format(formatter.parse(rStr));
} catch (Exception e) {
return false;
}
return true;
}