Java – How to compare strings in Java?
==
tests for reference equality (whether they are the same object).
.equals()
tests for value equality (whether they are logically “equal”).
Consequently, if you want to test whether two strings have the same value you will probably want to use Objects.equals()
.
// These two have the same value new String("test").equals("test") // --> true // ... but they are not the same object new String("test") == "test" // --> false // ... neither are these new String("test") == new String("test") // --> false // ... but these are because literals are interned by // the compiler and thus refer to the same object "test" == "test" // --> true // ... string literals are concatenated by the compiler // and the results are interned. "test" == "te" + "st" // --> true // ... but you should really just call Objects.equals() Objects.equals("test", new String("test")) // --> true Objects.equals(null, "test") // --> false Objects.equals(null, null) // --> true
Other Methods To Consider
String.equalsIgnoreCase() value equality that ignores case.
String.contentEquals() compares the content of the String
with the content of any CharSequence
(available since Java 1.5). Saves you from having to turn your StringBuffer, etc into a String before doing the equality comparison, but leaves the null checking to you.
Leave a Reply