Java 比较两个日期的方法，java两个日期方法,Java的日期类型比较可

Java 比较两个日期的方法，java两个日期方法,Java的日期类型比较可

Java的日期类型比较可以使用如下三种方法：

使用Date类的CompareTo方法使用Date类的equals(), before() 和after()方法使用Calendar类的equals(),before()和after()方法

[Java]代码

import java.text.DateFormat;import java.text.ParseException;import java.text.SimpleDateFormat;import java.util.Calendar;import java.util.Date;public class HashtableDemo {    public static void main(String args[]) throws AssertionError, ParseException {        DateFormat df = new SimpleDateFormat("dd-MM-yyyy");        //comparing date using compareTo method in Java        System.out.println("Comparing two Date in Java using CompareTo method");        compareDatesByCompareTo(df, df.parse("01-01-2012"), df.parse("01-01-2012"));        compareDatesByCompareTo(df, df.parse("02-03-2012"), df.parse("04-05-2012"));        compareDatesByCompareTo(df, df.parse("02-03-2012"), df.parse("01-02-2012"));        //comparing dates in java using Date.before, Date.after and Date.equals        System.out.println("Comparing two Date in Java using Date's before, after and equals method");        compareDatesByDateMethods(df, df.parse("01-01-2012"), df.parse("01-01-2012"));        compareDatesByDateMethods(df, df.parse("02-03-2012"), df.parse("04-05-2012"));        compareDatesByDateMethods(df, df.parse("02-03-2012"), df.parse("01-02-2012"));        //comparing dates in java using Calendar.before(), Calendar.after and Calendar.equals()        System.out.println("Comparing two Date in Java using Calendar's before, after and equals method");        compareDatesByCalendarMethods(df, df.parse("01-01-2012"), df.parse("01-01-2012"));        compareDatesByCalendarMethods(df, df.parse("02-03-2012"), df.parse("04-05-2012"));        compareDatesByCalendarMethods(df, df.parse("02-03-2012"), df.parse("01-02-2012"));    }    public static void compareDatesByCompareTo(DateFormat df, Date oldDate, Date newDate) {        //how to check if date1 is equal to date2        if (oldDate.compareTo(newDate) == 0) {            System.out.println(df.format(oldDate) + " and " + df.format(newDate) + " are equal to each other");        }        //checking if date1 is less than date 2        if (oldDate.compareTo(newDate) < 0) {            System.out.println(df.format(oldDate) + " is less than " + df.format(newDate));        }        //how to check if date1 is greater than date2 in java        if (oldDate.compareTo(newDate) > 0) {            System.out.println(df.format(oldDate) + " is greater than " + df.format(newDate));        }    }    public static void compareDatesByDateMethods(DateFormat df, Date oldDate, Date newDate) {        //how to check if two dates are equals in java        if (oldDate.equals(newDate)) {            System.out.println(df.format(oldDate) + " and " + df.format(newDate) + " are equal to each other");        }        //checking if date1 comes before date2        if (oldDate.before(newDate)) {            System.out.println(df.format(oldDate) + " comes before " + df.format(newDate));        }        //checking if date1 comes after date2        if (oldDate.after(newDate)) {            System.out.println(df.format(oldDate) + " comes after " + df.format(newDate));        }    }    public static void compareDatesByCalendarMethods(DateFormat df, Date oldDate, Date newDate) {        //creating calendar instances for date comparision        Calendar oldCal = Calendar.getInstance();        Calendar newCal = Calendar.getInstance();        oldCal.setTime(oldDate);        newCal.setTime(newDate);        //how to check if two dates are equals in java using Calendar        if (oldCal.equals(newCal)) {            System.out.println(df.format(oldDate) + " and " + df.format(newDate) + " are equal to each other");        }        //how to check if one date comes before another using Calendar        if (oldCal.before(newCal)) {            System.out.println(df.format(oldDate) + " comes before " + df.format(newDate));        }        //how to check if one date comes after another using Calendar        if (oldCal.after(newCal)) {            System.out.println(df.format(oldDate) + " comes after " + df.format(newDate));        }    }}

运行结果

Comparing two Date in Java using CompareTo method01-01-2012 and 01-01-2012 are equal to each other02-03-2012 is less than 04-05-201202-03-2012 is greater than 01-02-2012Comparing two Date in Java using Date's before, after and equals method01-01-2012 and 01-01-2012 are equal to each other02-03-2012 comes before 04-05-201202-03-2012 comes after 01-02-2012Comparing two Date in Java using Calendar's before, after and equals method01-01-2012 and 01-01-2012 are equal to each other02-03-2012 comes before 04-05-201202-03-2012 comes after 01-02-2012