使用tokenizer时验证空字符串

Question

I have a String like this: String sample = "a|b||d|e";
and I'm trying to split the string with tokenizer

StringTokenizer tokenizer = new StringTokenizer(sample, "|");
String a = tokenizer.nextToken();
String b = tokenizer.nextToken();
String c = tokenizer.nextToken();
String d = tokenizer.nextToken();

When I use the above code, the String variable c is assigned to the value d .
StringTokenizer doesn't initialize a null value to String c .

How can we validate and assign default value like - if it is null ?

Answer 1

As others have said, you can use String#split() on pipe, which would return an entry for the empty match. In the code snippet below, I use streams to map the empty entry into dash per your desired output.

String sample = "a|b||d|e";
String[] parts = sample.split("\\|");
List<String> list = Arrays.asList(parts).stream()
    .map(o -> {
        if (o.equals("")) {
            return "-";
        } else {
            return o;
        }
    }).collect(Collectors.toList());

for (String part : list) {
   System.out.println(part);
}

Output:

a
b
-
d
e

Demo here:

Rextester