Chris Mcgarel wrote:
> Can someone expalin to a novice why I must use:
> if (Request.Form("myFormElement").equals("myString"))
> rather than a straight comparison operator:
> if (Request.Form("myFormElement")=="myString")
> ?
>
> The latter does not work for me even though both left and right sides of the
> statement are Strings.
>
It never will work, either, if your intent is to see if the string contents are
identical. Strings are objects, not native data types. When you use the "=="
operator on objects in Java, you are comparing the object references for equality,
not the object contents. That's why you need to use the equals() function to
accomplish what you want.
Given:
String a = "abc";
String b = "abc";
if (a == b) {
System.out.println("Got a == b");
} else {
System.out.println("Got a != b");
}
if (a.equals(b)) {
System.out.println("Got a equals b");
} else {
System.out.println("Got a notequals b");
}
will print
Got a != b
Got a equals b
The same principle applies to other object types besides Strings -- the equals()
method is used to compare the contents of two objects for equality, while the ==
operator compares the two pointers to those objects.
Craig McClanahan
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