[Solved] Simplest way to validate string (Java) [closed]

Question

This is quite easy to o actually. Requirement #1 and #3 are the easiest. To test for whether a string contains two words and are separated by exactly one space, just use the split method. For requirement #2, test if the strings have a length that is larger than 2.

Let’s say your string to test is called str\

String str = "Jon Skeet";

You can create boolean variables to store the results of each test. It’s easier to understand.

String[] splitString = str.split(" ");
boolean test1 = splitString.length == 2;
boolean test2 = true;
for (String s : splitString) {
    if s.length() < 2 {
        test2 = false;
    }
}

As you can see, I actually combined the word count test and the “separated by one space” test into one. Because they can be tested simultaneously using one method.

Now you have test1 and test2. You just need to see if they are all true:

if (test1 && test2) {
    System.out.println("THE STRING IS VALID!");
}

You can even extract this as a method:

public static boolean isStringValid(String str) {
    String[] splitString = str.split(" ");
    boolean test1 = splitString.length == 2;
    boolean test2 = true;
    for (String s : splitString) {
        if s.length() < 2 {
            test2 = false;
        }
    }

    if (test1 && test2) {
        return true;
    }
    return false;
}

or you can do the test all in one go, although this is quite hard for people to understand what you are doing.

boolean test = splitString.length > 2 && splitString[0].length() >= 2 && splitString[0].length() >= 2;

EDIT:

If you want to see if it only contains letters, call Character.isLetter.

   boolean test2 = true;
   boolean test3 = true;
   for (String s : splitString) {
        for (int i = 0 ; i < s.length() ; i++) {
            if (!Character.isLetter(s.charAt(i))) {
                test3 = false;
            }
        }
        if (s.length() < 2 && ) {
            test2 = false;
            break;
        }
    }

Accepted Answer