String compare question.

Hi all,
I have this code here, and don't understand the result came out. Can someone explain this out come ? Thanks.
String s1 = "Hi";
String s2 = "Hi";
if (s1 ==s2) System.out.println("s1=s2");
String s3 = new String ("Hi");
String s4 = new String ("Hi");
if (s3 ==s4) System.out.println("s3=s4");
Result: It only prints "s1=s2". Why is that ?
Thanks.
Pwing

Hi all,
I have this code here, and don't understand the result
came out. Can someone explain this out come ?
Thanks.
String s1 = "Hi";s1 is created and put in to the string constant pool. When ever a String literal is encountered, the JVM will first check the string constant pool to see if it already contains a String object with the exactly same data(character sequence). If a match is found, a reference to the existing string is returned, and no new object is created.
String s2 = "Hi";string constant pool is checked and a string literal with the character sequence "Hi" already exists.
So, s1 and s2 are both references to the same object.
if (s1 ==s2) System.out.println("s1=s2");when comparing objects the == operation only tests to see if both references point to the same object. This is true since both s1 and s2 point to the same object in the string constant pool.
String s3 = new String ("Hi");
String s4 = new String ("Hi");A string created with the new operartor is not a string literal. The new operator always generates a unique object and returns a reference to that object.
if (s3 ==s4) System.out.println("s3=s4");
if you wish to compare the contents of a object use the .equals method.
Result: It only prints "s1=s2". Why is that ?
Thanks.
Pwing

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[svn] 1751: Bug: BLZ-174 - MessageClient.testMessage() is incorrectly doing a string compare for the subtopic header of an inbound message against the subtopic value (which may contain wildcards) that the Consumer is using.

Revision: 1751
Author: [email protected]
Date: 2008-05-15 14:21:43 -0700 (Thu, 15 May 2008)
Log Message:
Bug: BLZ-174 - MessageClient.testMessage() is incorrectly doing a string compare for the subtopic header of an inbound message against the subtopic value (which may contain wildcards) that the Consumer is using.
QA: No - customer verified the fix.
Doc: No
Ticket Links:
http://bugs.adobe.com/jira/browse/BLZ-174
Modified Paths:
blazeds/branches/3.0.x/modules/core/src/java/flex/messaging/MessageClient.java
blazeds/branches/3.0.x/modules/core/src/java/flex/messaging/services/MessageService.java

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I need to put together some static methods for parsing and comparing strings in different formats. I've written the skeleton methods with some nice comments below:
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Many long hours of messing around with string operations await me otherwise!
Thanks

I need to put together some static methods for
parsing and comparing strings in different formats.
I've written the skeleton methods with some nice
e comments below:Why isn't java.text.DateFormat good enough for you? I'll bet they do it better.
I'd use Locale for currencies.
This is a case where stuff that's already available to you should be preferred. Why write your own when someone else has already done it better? You don't have to maintain it, either. JMO, of course.
>
public class ParsingTools {
* This method should be able to convert a string
ring that contains
* a date in an arbitrary format, to a
to a java.util.date.
* E.G. '10.12.1998 4:15 AM', 'Jan 6th 1984',
84', '1/01/00'
* '24th Feb 1975 0530hrs'. The boolean 'usa'
usa' parameter indicates
* whether its usa style dates: mm/dd/yyyy,
yyy, instead of dd/mm/yyyy.
* @param inputDate
* @param usa
* @return
public static Date parseStringDate(String
ing inputDate, boolean usa){
Date outputDate = null;
return outputDate;
* This method should be able to convert strings
ings like:
* "$10,000.45" to the double 10000.45, or even:
* "'x=$$254,433,344.003'" to 254433344.00. All
All kinds of
* extraneous characters could be received, this
this method extracts
* and returns the number part.
* @param inputString
* @return
public static double parseMoneyString(String
ing inputString){
double outputDouble = 0.0;
return outputDouble;
* This method takes two strings, the first of
t of which is compared
* to the second to see if they are a close enough
ough match.
* E.G. " exerci$ed_" compared with "EXERCISED"
SED" should return
* true, but "elephant" compared with "EXERCISED"
SED" should return
* false.
* @param inputString
* @param compareString
* @return
public static boolean matchToString(String
ing inputString,
String
String
String compareString){
boolean matches = false;
return matches;
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is easy, just search through the string until you
find some numbers, and strip out any commas.
If anyone has any ideas on a clever way of doing the
date parsing, and the string compare one, or knows of
existing methods to do these, I'd love to hear about
it.
Many long hours of messing around with string
operations await me otherwise!
Thanks

Using wildcards for String compare

Hello,
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Thanx,
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You may use the String method startsWith to find strings beginning with File. eg. filename.startsWith("File")
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String Compare

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-mfp.
Solved!
Go to Solution.

Your question is extremely basic. PLEASE read the LabVIEW Help and do the tutorials. It's not a waste of time.
To learn more about LabVIEW it is recommended that you go through the tutorial(s) and look over the material in the NI Developer Zone's Learning Center which provides links to other materials and other tutorials. You can also take the online courses for free.
Attachments:
Example_VI_BD.png ‏2 KB

Why string compare is false?

Hello,
I've been confused for a while, could you mind helping?
This small code compare two strings, not know why but always false.
==
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==
why the two strings are not equal?
Hope you can help, thanks in advance.
Rgds, Dove

masijade. wrote:
Well, most of his questions lately, have been about MySQL, and "0000-00-00" is the way that MySQL (per default) represents invalid dates, and "YYYY-MM-DD" is the toString() pattern for a java.sql.Date instance. ;-)Sorry for keeping your guys waiting, but I've spent sometimes for reading more material as I can. Now the problem fixed.
The solution is liked this.
1) MySQL document said '0000-00-00' is a valid value for date in DB, but a wrong value for JDBC.
Detail:
http://dev.mysql.com/doc/refman/5.0/en/connector-j-installing-upgrading.html#connector-j-installing-upgrading-3-0-to-3-1
2) It is recognized as a problem, so it has been fixed. Instead of using old JDBC Connector/J, new version with re-configuration of zeroDateTimeBehavior can solve.
I configure it to convertToNull, so in Java I see all value 0000-00-00 from DB as null, works fine.
Many thanks the ideas from all of you.
Rgds, Dove

String a== string b question

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String compare problem

I try to compare 2 strings with compareTo/equalTo, but it's not working, those 2 funcs always return ture.
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When comparing strings, what is the different between using stringx.equals(stringy) and stringx == stringy?
And what is the different between threads that are created by implement Thread or extends Runnable.
They both work fine in my application

When comparing strings, what is the different between
using stringx.equals(stringy) and stringx ==
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And what is the different between threads that are
created by implement Thread or extends Runnable.
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Message was edited by:
tanmoy_rajguru
Message was edited by:
tanmoy_rajguru

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