writing an initialized static hashtable elegantly [duplicate]

This question already has answers here: Initializing Hashtables in Java? (10 answers) 开发者_开发百科 Closed 5 years ago.

Is there a way to write a static final Hashtable in java in key value pairs just like you can initialize a string array conveniently as :

String [] foo = {"A","AB"};

Basically what I mean is not having to write the words "put" for key:value pairs but instead may be something like:

Hashtable<String, String> foo = {"JJ":"222","KK":"222"}

which IMO looks more elegant.

(I know the initialization would need to be in a static block. I am leaving that out for now)

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An anonymous inner class would give you double brace initialization, which is useful in some cases:

static final Map<String, String> map = new HashMap<String, String>() {{
    put("foo", "bar");
    put("x", "y");
}};

In any case, @michael667's answer is probably the best

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You can use guava's ImmutableMap:

map = ImmutableMap.of(key1, value1, key2, value2);

These convenience methods exist for one to five elements. If you need more, you can use an ImmutableMap.Builder:

static final ImmutableMap<String, Integer> WORD_TO_INT =
   new ImmutableMap.Builder<String, Integer>()
     .put("one", 1)
     .put("two", 2)
     .put("three", 3)
     .build();

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No, Java doesn't have map literals, but it does have array literals.

static final Map<String, String> map;

static {
    map = new HashMap<String, String>();
    String[][] pairs = {
        {"foo", "bar"},
        {"x", "y"}
    };
    for (String[] pair : pairs) {
        map.put(pair[0], pair[1]);
    }
}

Of course this doesn't really add anything to the straightforward copy and paste put solution, and it doesn't work well if your key and value types aren't the same.

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No, you're looking for something like C#'s collection initializers, which doesn't currently exist in Java.

You can use an anonymous class to save a little typing, but you still have to write put.