java string matching problem

Question

I am facing a very basic problem. Some time small things can take your whole day :( but thank to stackoverflow memebers who always try to help :)

I am trying to match 2 strings if they match it should return TRUE

now I am using this

if (var1.indexOf(var2) >= 0) {
return true;
}

But if var1 has value "maintain" and var2 has value "inta" or "ain" etc. it still return true :(. Is there any way in java that can do full text matching not partial? For example

if("mango"=="mango"){
return true;
}

thanks ! ! !

hbw · Accepted Answer · 2010-02-23 01:18:47Z

5

Why not just use the built-in String equals() method?

return var1.equals(var2);

answered Feb 23, 2010 at 1:18

hbw

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Amir Afghani · Accepted Answer · 2010-02-23 01:18:57Z

4

if( "mango".equals("mango") ) { 
   return true;
}

Be careful not to use == for string comparisons in Java unless you really know what you're doing.

answered Feb 23, 2010 at 1:18

Amir Afghani

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2 Comments

Amir Afghani Over a year ago

== is comparing what the references point to, and .equals in the case of String is comparing the Strings lexicographically. In Java, you can create two new Strings that have the same content, and == will return false. In the contrived example you wrote, using == will most likely appear to work correctly, but if you created two String variables with the new operator and set the value to mango, it wouldn't work.

hbw Over a year ago

Here's a very rough analogy: var1 == var2 is like asking if two people are the same person, while var1.equals(var2) is like asking if two people have the same name.

Teja Kantamneni · Accepted Answer · 2010-02-23 01:22:43Z

3

use equals or equalsIgnoreCase on java.util.String for matching strings. You also need to check for null on the object you are comparing, I would generally prefer using commons StringUtils for these purposes. It has very good utils for common string operations.

answered Feb 23, 2010 at 1:22

Teja Kantamneni

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Comments

polygenelubricants · Accepted Answer · 2010-02-23 05:13:50Z

1

Here's an example to show why == is not what you want:

String s1 = new String("something");
String s2 = new String("something");
System.out.println(s1 == s2);
System.out.println(s1.equals(s2));

In effect, while s1 and s2 contains the same sequence of characters, they are not referring to the same location in memory. Thus, this prints false and true.

answered Feb 23, 2010 at 5:13

polygenelubricants

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