In Java, SimpleDateFormat is a concrete class that formats and parses dates in a locale-dependent manner. It allows formatting (date -> text), parsing (text -> date) and normalization, so judging whether a date is legal is also based on this.
import java.text.SimpleDateFormat; class Main { public static void main(String[] args) { String str1="2000-1-1"; String str2="2000-1-32"; System.out.println(check(str1)); System.out.println(check(str2)); } static boolean check (String str) { SimpleDateFormat sd=new SimpleDateFormat("yyyy-MM-dd");//括號內(nèi)為日期格式,y代表年份,M代表年份中的月份(為避免與小時中的分鐘數(shù)m沖突,此處用M),d代表月份中的天數(shù) try { sd.setLenient(false);//此處指定日期/時間解析是否不嚴格,在true是不嚴格,false時為嚴格 sd.parse(str);//從給定字符串的開始解析文本,以生成一個日期 } catch (Exception e) { return false; } return true; } }
In java, you can first use SimpleDateFormat to specify the date format, and then use the setLenien(false) method to strictly parse the date, and determine whether the date is legal by checking whether an exception is thrown.
setLenien:
SimpleDateFormat.setLenient(true): The default value is true, the date is not strictly parsed and will be automatically calculated.
SimpleDateFormat.setLenient(false): strictly parses the date. If the date is unqualified, an exception will be thrown and will not be automatically calculated.
For more java knowledge, please pay attention to the java basic tutorial column.
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