split string and store it into HashMap java 8

Question

I want to split below string and store it into HashMap.

String responseString = "name~peter-add~mumbai-md~v-refNo~"; 

first I split the string using delimeter hyphen (-) and storing it into ArrayList as below:

 public static List<String> getTokenizeString(String delimitedString, char separator) {
    final Splitter splitter = Splitter.on(separator).trimResults();
    final Iterable<String> tokens = splitter.split(delimitedString);
    final List<String> tokenList = new ArrayList<String>();
    for(String token: tokens){
        tokenList.add(token);
    }
    return tokenList;
}
List<String> list = MyClass.getTokenizeString(responseString, "-");

and then using the below code to convert it to HashMap using stream.

HashMap<String, String> = list.stream()
                          .collect(Collectors.toMap(k ->k.split("~")[0], v -> v.split("~")[1]));

The stream collector doesnt work as there is no value against refNo.

It works correctly if I have even number of elements in ArrayList.

Is there any way to handle this? Also suggest how I can use stream to do these two tasks (I dont want to use getTokenizeString() method) using stream java 8.

Answer 1

Unless Splitter is doing any magic, the getTokenizeString method is obsolete here. You can perform the entire processing as a single operation:

Map<String,String> map = Pattern.compile("\\s*-\\s*")
    .splitAsStream(responseString.trim())
    .map(s -> s.split("~", 2))
    .collect(Collectors.toMap(a -> a[0], a -> a.length>1? a[1]: ""));

By using the regular expression \s*-\s* as separator, you are considering white-space as part of the separator, hence implicitly trimming the entries. There’s only one initial trim operation before processing the entries, to ensure that there is no white-space before the first or after the last entry.

Then, simply split the entries in a map step before collecting into a Map.