String comparison to constant error

Question

Possible Duplicate:
How do I compare strings in Java?

I have this code its working fine in retreiving the value from the url, but its not recognizing that the string is "True" is the toString() what I need or something else?

try {
    URL url = new URL("http://www.koolflashgames.com/test.php?id=1");
    URLConnection yc = url.openConnection();
    BufferedReader in = new BufferedReader(new InputStreamReader(yc
            .getInputStream()));
    inputLine = in.readLine();
    inputLine = inputLine.toString();
    if(inputLine == "True") {
        logger.info(inputLine);
        player.sendMessage("Thanks");
    }else{
        logger.info(inputLine);
        player.sendMessage("HAHAHA");
    }
    in.close();
} catch (Exception e) {
    e.printStackTrace();
}

Use `equals` to compare strings, not `==` (reference equality). — Paul Bellora, Nov 04 '12 at 04:08
we must make a different stackexchange site for string-compare-problems in java. All of their answers end up nearly being "use .equals" — Aniket Inge, Nov 04 '12 at 04:09
@Aniket: That's what the "close as duplicate question" is for, isn't it? — hmakholm left over Monica, Nov 04 '12 at 04:11
@HenningMakholm yet none of these questions get marked as duplicates — Aniket Inge, Nov 04 '12 at 04:15
Since you are having only one line of text you won't need the toString() method — Sri Harsha Chilakapati, Nov 04 '12 at 04:17

Clark · Accepted Answer · 2012-11-04T04:10:07.457

4

You cannot use == to compare the content of Strings, as they are objects. You have to create a method to compare objects. In the case of strings, you can use stringName.equals(otherString).

edited Nov 04 '12 at 04:10

answered Nov 04 '12 at 04:08

Clark

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Well you *can* use `==` on objects, but it means something else. – Paul Bellora Nov 04 '12 at 04:09
Yeah, I should probably edit that in. – Clark Nov 04 '12 at 04:09
Thank you this fixed my problem. Sorry if my question seemed so obvious, I've just started to work with java. – arennaker Nov 04 '12 at 04:12
You're welcome. We all start somewhere :) – Clark Nov 04 '12 at 04:14

thedayofcondor · Answer 2 · 2012-11-04T04:14:51.153

3

You must use equals to compare strings. Replace:

if(inputLine == "True") {

with:

if(inputLine.equals("True")) {

The operator == tells you if two references refer to the same object, not if the values are the same.

edited Nov 04 '12 at 04:14

answered Nov 04 '12 at 04:08

thedayofcondor

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score 3 · Answer 3 · answered Nov 04 '12 at 04:11

3

I beg to differ. Use .equalsIgnoreCase() method to compare the string ignoring the case. This will match all cases, such as "True", "TRue", "tRue".. etc approximately 16 matches.

answered Nov 04 '12 at 04:11

Aniket Inge

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What if he does not want that functionality? But still, a helpful suggestion +1. – eboix Nov 04 '12 at 04:12
it will still match his string @eboix :-P – Aniket Inge Nov 04 '12 at 04:13
I like to use `.equalsWithTypos()` so it matches stuff like "treu" and "ture". – Paul Bellora Nov 04 '12 at 04:17
@PaulBellora I use `equalsWithSpeech` that matches phonetically similar sounding words. – Aniket Inge Nov 04 '12 at 04:19

score 2 · Answer 4 · edited May 23 '17 at 12:04

2

In order to compare String objects, use the equals() method.

The == operator checks whether the two Strings have the same reference.

See How do I compare strings in Java? for more info.

edited May 23 '17 at 12:04

Community

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answered Nov 04 '12 at 04:08

eboix

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String comparison to constant error

4 Answers4