Java Date Conversion

Question

In the following code input:

Enter Date: 3/2/2011

Output:

Entered Date is February 3, 2011
Entered Month is 02

Problem is , when i input this date 3/14/2012, the date format function automatically changes month to 12+2(February). If I put 13/15/2011, it will change month to 3(12+3).

It should give an error on 14 that "invalid month"

package lesson4;

import java.util.*;

import java.text.*;
public class ConvertDate {
static String Month;
static String fulldate;
static int month;
static  int[] montharray={1,2,3,4,5,6,7,8,9,10,11,12};
public static void main(String[] args){


Scanner sc = new Scanner(System.in); 
System.out.print("Enter Date: "); 
String ind = sc.nextLine(); 
//Date now = new Date();
DateFormat df = new SimpleDateFormat("dd/MM/yyyy");
SimpleDateFormat f = new SimpleDateFormat("dd");
SimpleDateFormat m = new SimpleDateFormat("MM");

Date d = null;
    Date e=null;
Date g=null;


try {
d=df.parse(ind);
e=df.parse(ind);
g=df.parse(ind);
DateFormat df3 = DateFormat.getDateInstance(DateFormat.LONG);


 fulldate = df3.format(d);
 Month=m.format(g);
month =Integer.parseInt(Month);

String date  =f.format(e);
 } catch (ParseException e1) {
// TODO Auto-generated catch block



e1.printStackTrace();
}





System.out.println("The entered date is: " + fulldate);
System.out.println("The entered month is: " + Month);

}
}

@Nizil. No it won't be. DateFormat is the correct way to do this. — Rohit Jain
– Rohit Jain, Commented Aug 2, 2013 at 7:28
@RohitJain I agree, DateFormat is so much better than string parsing, but forgot the setLenien(bool) and didn't see another solution before you post your answer ;) — NiziL
– NiziL, Commented Aug 2, 2013 at 7:30

Rohit Jain · Accepted Answer · 2013-08-02 07:31:15Z

4

For each of your DateFormat instance, you need to invoke setLenient with false argument:

DateFormat df = new SimpleDateFormat("dd/MM/yyyy");
df.setLenient(false);
DateFormat f = new SimpleDateFormat("dd");
f.setLenient(false);
DateFormat m = new SimpleDateFormat("MM");
m.setLenient(false);

From DateFormat#setLenient(boolean) documentation:

With lenient parsing, the parser may use heuristics to interpret inputs that do not precisely match this object's format. With strict parsing, inputs must match this object's format.

edited Aug 2, 2013 at 7:31

answered Aug 2, 2013 at 7:25

Rohit Jain

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14 Comments

James Blent Over a year ago

great Rohit..but can i want to check the month from array..i am restricted to use arrays if i enter 14 in month then it should display invalid month,....Your code is only catching exception

Rohit Jain Over a year ago

@JamesBlent. You can catch the exception, and display your own message. You can search for some good Exception Handling tutorial.

James Blent Over a year ago

Yes i have cached exception that "Invalid Date"..but how can i give error using array..i have declared array in the code...please help

Rohit Jain Over a year ago

@JamesBlent. What do you mean by give error using array? Can you be more specific?

James Blent Over a year ago

yes ...i want that if i enter date 14/14/2011..It should give an error that invalid month...I want that i check input value of month(14) convert it to int and compare it to my declared array..

|

Zaheer Ahmed · Accepted Answer · 2013-08-02 07:21:49Z

2

Reference these formats Java Date Format Docs:

Formats for datetime

DateFormat df = new SimpleDateFormat("dd/MM/yyyy");

you are expecting Month at second place while input is placing it on first.

try:

DateFormat df = new SimpleDateFormat("MM/dd/yyyy");

answered Aug 2, 2013 at 7:21

Zaheer Ahmed

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Comments

Basil Bourque · Accepted Answer · 2025-01-27 04:46:30Z

1

tl;dr

Formatting pattern must match your actual inputs.

java.time.LocalDate.parse ( "3/14/2012" , DateTimeFormatter.ofPattern ( "M/d/uuuu" )  )

java.time

In modern Java (8+), use only the java.time classes for date-time work. Never use Calendar nor SimpleDateFormat.

Your formatting pattern failed to match your input. Get your month number and day-of-month codes in the right place.

Another problem in your code: Use single d & M if not padding with leading zero for single-digit values. If padding, use double dd & MM.

DateTimeFormatter f = DateTimeFormatter.ofPattern ( "M/d/uuuu" ) ;
LocalDate ld = LocalDate.parse ( "3/14/2012" , f ) ;

To detect invalid inputs, trap for DateTimeParseException.

answered Jan 27 at 4:46

Basil Bourque

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Comments

Christian Kullmann · Accepted Answer · 2013-08-02 07:25:51Z

0

Have you tried using "setLenient(false)" on your DateFormat to force the DateFormat to be strict about the parsed input? I haven't tried it yet, but stumbled across this feature recently.

answered Aug 2, 2013 at 7:25

Christian Kullmann

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