将值分配给地图（哈希图或多图）

Question

I have a map :

HashMap<String, ArrayList<Integer>> hashmap = new HashMap<String, ArrayList<Integer>>();

After retrieving data from a remote database server, I am creating a hashmap:(output in eclipse)

{newcomer=[23, 78, 118, 155, 240, 244], zoom=[213], profession=[8, 10, 12, 13, 15]}

Now, my concern is, it is taking too much of time to connect to server and download data. Size of data is beyond limit of my patience. Is there any way, I can store value directly in a Hashmap variable (like we do with normal variables, int i =5);

In general, how can I do this (like I do in Python) :

hashmap = {newcomer=[23, 78, 118, 155, 240, 244], zoom=[213], profession=[8, 10, 12, 13, 15]}

I have switched to Guava recently, Can I do this Multimap as well? Value I want to assign is now a string, so assigning might be much more complicated than I am thinking.

Edit 1 : I need this for development purpose only. Once application is live, will reconnect to database server.

Edit 2 : I have nearly 50k pairs at this moment, hence adding individually is not an option. May, for development, I can trim list to 100 items, but that too involve labor to put each one.

Edit 3 : I understand we can figure out someway or other to setup database more perfectly for fast execution. I only need to figure out that is it possible to assign? Else, I am going for local setup.

Answer 1

Inline initialization of Map s is not possible in Java. In your case this doesn't matter however -- with the amout of data you have populating the Map via code either means hours (or days) of highly repetetive and extremely error-prone manual typing or writing a code generator:

I have nearly 50k pairs at this moment, hence adding individually is not an option.

And if you write a code generator anyway, it doesn't matter if it generates an inline initializer or loads of Map#put() statements.

However, code generation / initialization in code certainly is a bad choice in this case anyway. Better solutions would be (sorted by decreasing usefulness):

• Take care of your slow database setup or unoptimized query (see comment from CBass to the original question).
• Take care to only load that data once, making the delay less relevant to the big picture.
• Read it from the DB server once, then serialize it to a file (see ObjectOutputStream ) and deserialize it from there afterwards.
• You could set up a local (fast) database server and read from that instead of the remote one.

I wouldn't even think of initializing a data structure of this size in code unless all the above things have been shown to not work. Which is extremely unlikely.