How to check if a date is greater than another in Java? [duplicate]

Question

I am working on a Java application which generates a report for a duration entered by a user in the command line. The user needs to enter the dates in the following format: dd-MM-yyyy

> java report startDate endDate

Example:

java report 01-01-2013 31-03-2013

In the code I save the dates in two strings. I have to make sure that the start date entered by the user should be a date earlier than the end-date. Is there an built-in function which can help me achieve this by passing these two strings to it?

Answer 1

You can use Date.before() or Date.after() or Date.equals() for date comparison.

Taken from here:

import java.text.ParseException; import java.text.SimpleDateFormat; import java.util.Date;  public class DateDiff {      public static void main( String[] args )     {         compareDates("2017-01-13 00:00:00", "2017-01-14 00:00:00");// output will be Date1 is before Date2         compareDates("2017-01-13 00:00:00", "2017-01-12 00:00:00");//output will be Date1 is after Date2         compareDates("2017-01-13 00:00:00", "2017-01-13 10:20:30");//output will be Date1 is before Date2 because date2 is ahead of date 1 by 10:20:30 hours         compareDates("2017-01-13 00:00:00", "2017-01-13 00:00:00");//output will be Date1 is equal Date2 because both date and time are equal     }      public static void compareDates(String d1,String d2)     {         try{             // If you already have date objects then skip 1              //1             // Create 2 dates starts             SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");             Date date1 = sdf.parse(d1);             Date date2 = sdf.parse(d2);              System.out.println("Date1"+sdf.format(date1));             System.out.println("Date2"+sdf.format(date2));System.out.println();              // Create 2 dates ends             //1              // Date object is having 3 methods namely after,before and equals for comparing             // after() will return true if and only if date1 is after date 2             if(date1.after(date2)){                 System.out.println("Date1 is after Date2");             }             // before() will return true if and only if date1 is before date2             if(date1.before(date2)){                 System.out.println("Date1 is before Date2");             }              //equals() returns true if both the dates are equal             if(date1.equals(date2)){                 System.out.println("Date1 is equal Date2");             }              System.out.println();         }         catch(ParseException ex){             ex.printStackTrace();         }     }      public static void compareDates(Date date1,Date date2)     {         // if you already have date objects then skip 1         //1          //1          //date object is having 3 methods namely after,before and equals for comparing         //after() will return true if and only if date1 is after date 2         if(date1.after(date2)){             System.out.println("Date1 is after Date2");         }          //before() will return true if and only if date1 is before date2         if(date1.before(date2)){             System.out.println("Date1 is before Date2");         }          //equals() returns true if both the dates are equal         if(date1.equals(date2)){             System.out.println("Date1 is equal Date2");         }          System.out.println();     } } 

Answer 2

Parse the string into date, then compare using compareTo, before or after

Date d = new Date(); d.compareTo(anotherDate) 

i.e

Date date1 = new SimpleDateFormat("MM/dd/yyyy").parse(date1string) Date date2 = new SimpleDateFormat("MM/dd/yyyy").parse(date2string)  date1.compareTo(date2); 

Copying the comment provided below by @MuhammadSaqib to complete this answer.

Returns the value 0 if the argument Date is equal to this Date; a value less than 0 if this Date is before the Date argument, and a value greater than 0 if this Date is after the Date argument. and NullPointerException - if anotherDate is null.

javadoc for compareTo http://docs.oracle.com/javase/6/docs/api/java/util/Date.html#compareTo(java.util.Date)