How to get a specific part of a string in java

Question

I'm developing an Android app that gets the date from the internet. What I have is a complete date format like this one : 2020-06-13T16:21:15.239920+02:00. I want to get the day of the month (which is 13 in this case).

You can use String functions to get date based upon character positions or you can use data/time formatter available in java to get the date — Nitin Bisht, Jun 13 '20 at 14:57
@NitinBisht but how to get it based upon character positions (I'm beginner) — Mohamed Hassan, Jun 13 '20 at 15:00
If you only want it for this format you can use YOUR_STRING.substring(8,10); — Wowo Ot, Jun 13 '20 at 15:01
@Everyone Please don’t use string functions. Use date-time functions like the top-voted answers say. — Ole V.V., Jun 13 '20 at 17:08
If you’ve got two strings `2020-06-13T23:59:01.239920-12:00` and `2020-06-13T00:00:15.239920+14:00`, do you want 13 in both cases? There are almost 50 hours, more than 2 days, between the two points in time. — Ole V.V., Jun 13 '20 at 17:24

score 2 · Answer 1 · edited Jun 13 '20 at 20:59

2

Your date/time string complies with DateTimeFormatter.ISO_OFFSET_DATE_TIME. You can use java.time API to get the day of the month as shown below:

import java.time.OffsetDateTime;

public class Main {
    public static void main(String[] args) {
        String dateTimeStr = "2020-06-13T16:21:15.239920+02:00";
        OffsetDateTime odt = OffsetDateTime.parse(dateTimeStr);
        int day = odt.getDayOfMonth();
        System.out.println(day);
    }
}

Output:

If you can not use Java SE 8 Date and Time, check ThreeTenABP and also How to use ThreeTenABP in Android Project.

edited Jun 13 '20 at 20:59

Basil Bourque

303,325
100
852
1,154

answered Jun 13 '20 at 15:03

Arvind Kumar Avinash

71,965
6
74
110

1

OffsetDateTime.parse interprets the string in DateTimeFormatter.ISO_OFFSET_DATE_TIME by default. So, you can simplify for the OP's case by dropping specifying the format and the ZoneOffset and get the same result. – jmrah Jun 13 '20 at 15:11
@jrahhali - Thanks for the suggestion. I've updated my answer to incorporate it. – Arvind Kumar Avinash Jun 13 '20 at 15:57

score 2 · Accepted Answer · answered Jun 13 '20 at 15:05

If you are using at least API level 26, then you can use ZonedDateTime class as your string uses the default format that is understood by that class.

ZonedDateTime zdt = ZonedDateTime.parse("2020-06-13T16:21:15.239920+02:00");
int d = zdt.getDayOfMonth();

Alternatively, if the format is constant, simply use method substring()

String dd = "2020-06-13T16:21:15.239920+02:00".substring(8, 10);

If the format is not constant, I would suggest either regular expression or combining ZonedDateTime with DateTimeFormatter

`ZonedDateTime` isn’t necessary. `OffsetDateTime` will do since the string contains an offset, +02:00, not a time zone like Asia/Jerusalem. Otherwise a good answer. — Ole V.V., Jun 13 '20 at 17:06

score 0 · Answer 3 · edited Jun 13 '20 at 21:11

0

String str = "2020-06-13T16:21:15.239920+02:00";
String substr = "";

// prints the substring after index 7(8 includes) till index 9(10 excludes)
substr = str.substring(8, 10);

edited Jun 13 '20 at 21:11

Littm

4,923
4
30
38

answered Jun 13 '20 at 15:00

Md Aman

340
3
10

1

While this code may answer the question, providing additional context regarding why and/or how this code answers the question improves its long-term value. – β.εηοιτ.βε Jun 13 '20 at 18:45

score 0 · Answer 4 · answered Jun 13 '20 at 15:03

Its always a bad idea to split a string and extract data becuase the string will change to some other value once the date , month or any part of the date string changes and the string indexing will change

So use DateTimeFormatter

import java.time.MonthDay;
import java.time.format.DateTimeFormatter;
import java.time.temporal.TemporalAccessor;

public class SDF {

    public static void main(String[] args) {
        final TemporalAccessor parse = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss.SSSSSSxxx")
                .parse("2020-06-13T16:21:15.239920+02:00");

        int dayOfMonth = MonthDay.from(parse).getDayOfMonth();
        System.out.println(dayOfMonth);
    }
}

score 0 · Answer 5 · answered Jun 13 '20 at 15:06

0

There should be a method getDayOfMonth() available on this variable

private int parseDate(ZonedDateTime date) {
    int day = date.getDayOfMonth();
    return day;
}

answered Jun 13 '20 at 15:06

Robert Głowacki

292
5
22

The given input `2020-06-13T16:21:15.239920+02:00` is appropriate for `OffsetDateTime` class rather than `ZonedDateTime`. See the [Answer by Avinash](https://stackoverflow.com/a/62361576/642706). – Basil Bourque Jun 13 '20 at 20:57

score 0 · Answer 6 · answered Jun 13 '20 at 15:10

0

You can use String split. Just take this whole format of date and put it into String and then create a new String Array String[] array= str.split("[-T]"); and then you can get result from array[2].

String str = "2020-06-13T16:21:15.239920+02:00";
String[] array= str.split("[-T]");

System.out.println("OUTPUT: " + array[2]);

Output: 13

answered Jun 13 '20 at 15:10

Šimon Slabý

533
1
4
18

While the code in this Answer may work we have a purpose-built class for this: [`java.time.OffsetDateTime`](https://duckduckgo.com/?q=offsetdatetime+java+11&t=osx&ia=web). See the [Answer by Avinash](https://stackoverflow.com/a/62361576/642706). – Basil Bourque Jun 13 '20 at 20:55

How to get a specific part of a string in java

6 Answers6