get string value from HashMap depending on key name

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误落风尘
误落风尘 2020-11-28 21:39

I have a HashMap with various keys and values, how can I get one value out?

I have a key in the map called my_code, it should contain a str

10条回答
  •  北荒
    北荒 (楼主)
    2020-11-28 22:08

    Just use Map#get(key) ?

    Object value = map.get(myCode);
    

    Here's a tutorial about maps, you may find it useful: http://java.sun.com/docs/books/tutorial/collections/interfaces/map.html.

    Edit: you edited your question with the following:

    I'm expecting to see a String, such as "ABC" or "DEF" as that is what I put in there initially, but if I do a System.out.println() I get something like java.lang.string#F0454

    Sorry, I'm not too familiar with maps as you can probably guess ;)

    You're seeing the outcome of Object#toString(). But the java.lang.String should already have one implemented, unless you created a custom implementation with a lowercase s in the name: java.lang.string. If it is actually a custom object, then you need to override Object#toString() to get a "human readable string" whenever you do a System.out.println() or toString() on the desired object. For example:

    @Override
    public String toString() {
        return "This is Object X with a property value " + value;
    }
    

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