在 Java 中比較日期的多種方式有哪些?
使用 LocalDate 類
java.time.LocalDate 類表示本地日期,即不含時區的日期,你可以使用此物件,而不是 Date。此類提供多種方法,如 isBefore()、isAfter() 和 isEqual(),以比較兩個日期 -
示例
import java.time.LocalDate;
public class Sample {
public static void main(String args[]) {
LocalDate date1 = LocalDate.of(2007, 11, 25);
LocalDate date2 = LocalDate.of(1999, 9, 12);
Boolean bool1 = date1.isAfter(date2);
Boolean bool2 = date1.isBefore(date2);
Boolean bool3 = date1.isEqual(date2);
if(bool1){
System.out.println(date1+" is after "+date2);
}else if(bool2){
System.out.println(date1+" is before "+date2);
}else if(bool3){
System.out.println(date1+" is equla to "+date2);
}
}
}輸出
2007-11-25 is after 1999-09-12
使用 Date 類
java.util.Date 類表示特定時間。此類提供多種方法,如 before()、after() 和 equals(),以比較兩個日期 -
示例
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.time.LocalDate;
import java.util.Date;
public class Sample {
public static void main(String args[]) throws ParseException {
SimpleDateFormat formatter = new SimpleDateFormat("yyyy-dd-MM");
//Parsing the given String to Date object
Date date1 = formatter.parse("2007-11-25");
Date date2 = formatter.parse("1999-9-12");
Boolean bool1 = date1.after(date2);
Boolean bool2 = date1.before(date2);
Boolean bool3 = date1.equals(date2);
if(bool1){
System.out.println(date1+" is after "+date2);
}else if(bool2){
System.out.println(date1+" is before "+date2);
}else if(bool3){
System.out.println(date1+" is equals to "+date2);
}
}
}輸出
Sun Jan 11 00:00:00 IST 2009 is after Thu Dec 09 00:00:00 IST 1999
使用 Calendar 類
與 Date 類類似,Calendar 類提供多種方法,如 before()、after() 和 equals(),以比較兩個日期 -
示例
import java.util.Calendar;
public class Sample {
public static void main(String args[]) {
Calendar obj1 = Calendar.getInstance();
obj1.set(2007, 11, 25);
Calendar obj2 = Calendar.getInstance();
obj2.set(1999, 9, 15);
Boolean bool1 = obj1.after(obj2);
Boolean bool2 = obj1.before(obj2);
Boolean bool3 = obj1.equals(obj2);
if(bool1){
System.out.println(obj1+" is after "+obj2);
}else if(bool2){
System.out.println(obj1+" is before "+obj2);
}else if(bool3){
System.out.println(obj1+" is equla to "+obj2);
}
}
}輸出
java.util.GregorianCalendar[time=?,areFieldsSet=false,areAllFieldsSet=true,lenient=true,zone=sun.util.calendar.ZoneInfo[id="Asia/Calcutta",offset=19800000,dstSavings=0,useDaylight=false,transitions=7,lastRule=null],firstDayOfWeek=1,minimalDaysInFirstWeek=1,ERA=1,YEAR=2007,MONTH=11,WEEK_OF_YEAR=45,WEEK_OF_MONTH=1,DAY_OF_MONTH=25,DAY_OF_YEAR=312,DAY_OF_WEEK=7,DAY_OF_WEEK_IN_MONTH=1,AM_PM=1,HOUR=9,HOUR_OF_DAY=21,MINUTE=33,SECOND=47,MILLISECOND=366,ZONE_OFFSET=19800000,DST_OFFSET=0] is after java.util.GregorianCalendar[time=?,areFieldsSet=false,areAllFieldsSet=true,lenient=true,zone=sun.util.calendar.ZoneInfo[id="Asia/Calcutta",offset=19800000,dstSavings=0,useDaylight=false,transitions=7,lastRule=null],firstDayOfWeek=1,minimalDaysInFirstWeek=1,ERA=1,YEAR=1999,MONTH=9,WEEK_OF_YEAR=45,WEEK_OF_MONTH=1,DAY_OF_MONTH=15,DAY_OF_YEAR=312,DAY_OF_WEEK=7,DAY_OF_WEEK_IN_MONTH=1,AM_PM=1,HOUR=9,HOUR_OF_DAY=21,MINUTE=33,SECOND=47,MILLISECOND=392,ZONE_OFFSET=19800000,DST_OFFSET=0]
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