用Java填充Hashmap

Question

Ok I am having quite a bit of an issue. I want to populate my hash map with a set of String keywords. So basically, The user enters a keyword and if it matches the keyword in the hash map a parseFile method is called. Else if the user input is a synonym of the keyword, I search the hash map for the original keyword. But my issue is populating the hash map. Can anyone guide me in the right direction?

 public static void main(String[] args) throws FileNotFoundException {

    /* your synonym map of keywords and you have to populate 
    it before the user can give values.*/ 
    HashMap<String, String[]> synonymMap = new HashMap<String, String[]>();
    populateSynonymMap(); //populate the map


    /*Get user response*/ 
    System.out.println("What would you like to know?");
    System.out.print("> ");
    Scanner scanner = new Scanner(System.in);
    String input = scanner.nextLine().toLowerCase();

    /*first check if the input already is the original one*/
    if (synonymMap.containsKey(input)) {
        parseFile(input);
    } else {
        /*if not then search the synonymMap to get the original keyword*/
        for (Map.Entry<String,String[]> entry : synonymMap.entrySet()) {

            String[] value = entry.getValue();                
            if (Arrays.asList(value).contains(input)) {
                parseFile(entry.getKey());
                break;
            }
        }
    }

}

Answer 1

May be you can try the following code. This does what you like to accomplish. But I think you need to think of redesigning the way you are looking up keyword synonym.

And if you are facing issues only populating the hashmap it may be because you are defining map inside main method and then not populating it really anywhere else.

So for the second option, you can change assignment in main method like ..

    synonymMap = populateSynonymMap(); // populate the map

And the sample method to populate the map.

private static HashMap<String, String[]> populateSynonymMap() {
    HashMap<String, String[]> synonymMap = new HashMap<String, String[]>();

    String s[] = new String[] { "x1", "x2", "x3" };
    String t[] = new String[] { "y1", "y2", "y3" };
    String u[] = new String[] { "z1", "z2", "z3" };

    synonymMap.put("x", s);
    synonymMap.put("y", t);
    synonymMap.put("z", u);

    return synonymMap;

}

Answer 2

You must define a method accepting a Map to populate

public void populateSynonymMap(Map<String, String[]> synonymsMap)

or declare your Map as attribute in the class to be visible in the method.

Then inside method you must have a word and synonyms array:

String word = "synonym";
String[] synonyms = "equivalent,methonim".split(",");

Then put both in the map:

synonimsMap.put(word, synonyms);

Do it as many times as you need (if a lot, define 2 arrays, one String[] for words and another String[][] for synonims and iterate over them to populate the map in an easier way...

String[] words = // populate word array
String[][] synonims = // populate synonims 2d array

for (int c = 0; c < words.length; c++) {
    synonimsMap.put(words[c], synonyms[c]);
}

Hope this guides you enough...

Answer 3

Rather than declaring you HashMap as

HashMap<String, String[]> synonymMap = new HashMap<String, String[]>();

Why don't you declare is as

HashMap<String, List<String>> synonymMap = new HashMap<String, ArrayList<String>>();

& then arrayListObj.add(entry.getValue());

then it will obviate the need for this Arrays.asList(value)

Initialize the method like

public void populateSynonymMap(String key, List<String> value){
    synonymMap.put(key, value);
    }

Input values in the List

List<String> listOne=new ArrayList<String>();
listOne.add("Input String"); //Keep on adding the Strings in this way
//then call the populateSynonymMap method
//Say your key is A
populateSynonymMap("A", listOne);