How to convert / cast long to String?

Question

I just created sample BB app, which can allow to choose the date.

DateField curDateFld = new DateField("Choose Date: ",
  System.currentTimeMillis(), DateField.DATE | DateField.FIELD_LEFT);

After choosing the date, I need to convert that long value to String, so that I can easily store the date value somewhere in database. I am new to Java and Blackberry development.

long date = curDateFld.getDate();

How should I convert this long value to String? Also I want to convert back to long from String. I think for that I can use long l = Long.parseLong("myStr");?

score 409 · Answer 1 · edited May 16 '14 at 14:16

409

See the reference documentation for the String class: String s = String.valueOf(date);

If your Long might be null and you don't want to get a 4-letter "null" string, you might use Objects.toString, like: String s = Objects.toString(date, null);

EDIT:

You reverse it using Long l = Long.valueOf(s); but in this direction you need to catch NumberFormatException

edited May 16 '14 at 14:16

Arnout Engelen

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answered Dec 06 '09 at 10:00

Gregory Pakosz

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Note that `Long.valueOf(String)` returns a `Long`. If you want a `long`, use `Long.parseLong(String)`. – Daniel Hepper Oct 26 '11 at 05:33
1

What's the differente between this way, or just concat like this: ("" + longAttr) ? – Marcelo Assis Feb 08 '12 at 13:05
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@MarceloAssis.. concat is about 2x slower. If performance matters in you application. – Hari Menon Feb 25 '12 at 14:14
Nice, but note that ``java.util.Objects`` is only available since Java 7. – Guillaume Husta Jul 23 '14 at 09:12
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Before Java 7, you could also use Commons Lang's ``ObjectUtils.toString(Object,String)`` which is equivalent. -> https://commons.apache.org/proper/commons-lang/javadocs/api-2.6/org/apache/commons/lang/ObjectUtils.html#toString(java.lang.Object, java.lang.String) – Guillaume Husta Jul 23 '14 at 09:59

score 231 · Answer 2 · answered Apr 11 '12 at 18:09

231

String strLong = Long.toString(longNumber);

Simple and works fine :-)

answered Apr 11 '12 at 18:09

Fisu

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For general type conversion outside the `Date` context this is the recommended practise to convert `Long` to `String`. – KomodoDave Sep 06 '12 at 10:35
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Works fine with primitive type (long), but may throw NPE with Object type (Long), even with autoboxing. – Guillaume Husta Jul 23 '14 at 09:20

Pedro Lobito · Answer 3 · 2023-05-03T20:46:16.223

108

`Long.toString()`

This should work:

long myLong = 1234567890123L;
String myString = Long.toString(myLong);

edited May 03 '23 at 20:46

answered Sep 20 '14 at 14:52

Pedro Lobito

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Is there any difference to `String.valueOf(myLong)`? – membersound Sep 29 '17 at 08:11
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@membersound they're the same. Basically String.valueOf(long) calls Long.toString() – Nero Mar 09 '18 at 20:36
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@Nero I wouldn't call the same because String.valueOf() will return "null" in case of null, while Long.toString() will cause NullPointerException – Dhiresh Jain Apr 27 '19 at 15:05

score 20 · Answer 4 · edited Sep 19 '11 at 18:12

20

very simple, just concatenate the long to a string.

long date = curDateFld.getDate(); 
String str = ""+date;

edited Sep 19 '11 at 18:12

Flexo

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answered Sep 19 '11 at 15:29

MR.M

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score 10 · Answer 5 · edited Jul 18 '16 at 09:54

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1.

long date = curDateFld.getDate();
//convert long to string
String str = String.valueOf(date);

//convert string to long
date = Long.valueOf(str);

2.

 //convert long to string just concat long with empty string
 String str = ""+date;
//convert string to long

date = Long.valueOf(str);

edited Jul 18 '16 at 09:54

user207421

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answered Apr 12 '12 at 04:30

iKushal

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score 3 · Answer 6 · edited Jul 18 '16 at 09:48

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String logStringVal= date+"";

Can convert the long into string object, cool shortcut for converting into string...but use of String.valueOf(date); is advisable

edited Jul 18 '16 at 09:48

Aditya Vyas-Lakhan

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answered Nov 18 '13 at 10:41

MBR

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I thought `String.valueOf` was the preferred approach but I noticed that just calls `Long.toString` so maybe that's the simpler way. – gMale Nov 17 '14 at 18:39

score 3 · Answer 7 · answered Sep 07 '20 at 08:35

3

Just do this:

String strLong = Long.toString(longNumber);

answered Sep 07 '20 at 08:35

Anushil Kumar

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score 2 · Answer 8 · answered Jan 09 '17 at 16:13

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String longString = new String(""+long);

or

String longString = new Long(datelong).toString();

answered Jan 09 '17 at 16:13

Nathan Meyer

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It's good practice on Stack Overflow to add an explanation as to why your solution should work. For more information read [How To Answer](http://stackoverflow.com/help/how-to-answer). – Fabian Schultz Jan 09 '17 at 17:25
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This does not provide an answer to the question. To critique or request clarification from an author, leave a comment below their post. - [From Review](/review/low-quality-posts/14830916) – Krupal Shah Jan 09 '17 at 18:13
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@KrupalShah A code-only answer might not be a good one, but it's still an answer. I would recommend you this post about the LQPRQ: [You're doing it wrong: A plea for sanity in the Low Quality Posts queue](http://meta.stackoverflow.com/questions/287563/youre-doing-it-wrong-a-plea-for-sanity-in-the-low-quality-posts-queue) – FelixSFD Jan 09 '17 at 18:33

How to convert / cast long to String?

8 Answers8

`Long.toString()`

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