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javamysql
Biscuit128
Biscuit128

Reputation: 5398

Java - select from array of values

I was wondering if it is possible to do a select * where value is in Java String[] or do I need to build a string of values from the string array first?

I am trying to find the best way of doing this technically without singular selects or building a string of values from the array.

Thanks for your time.

String[] lookupValues = new String[]{"1", "2", "3", "4"};
Select * from database where value in (lookupvalues)

Upvotes: 0

Views: 3634

Answers (3)

user987339
user987339

Reputation: 10707

I know that this is not a direct answer to your question considering only arrays. I suggest you to use Guava since it offers a implementation of filter on Java Collections. Using proven libraries will give you flexibility if you use different kind of filters.

You can easily convert your array into proper collection 

String[] lookupValues = new String[]{"1", "2", "3", "4"};
List<String> list = new ArrayList<String>(Arrays.asList(lookupValues));

And filter it with Guava filters:

Collection<String> filtered = Collections2.filter(list,
    Predicates.containsPattern("3"));
print(filtered);

will find

3

If you want filtered collection as a list, you can use this something like this from Guava:

List<String> filteredList = Lists.newArrayList(Collections2.filter(
    list, Predicates.containsPattern("3")));

Upvotes: 0

Amit Sharma
Amit Sharma

Reputation: 6154

try Arrays.toString(lookupvalues) or write a utility function.

    public String toString(String[] values, boolean addQuotes) {

        StringBuilder buff = new StringBuilder();
        for(String value : values) {
            if(addQuotes) {
                buff.append(String.format("\"%s\"", value)).append(",");
            } else {
                buff.append(value).append(",");
            }
        }
        buff.deleteCharAt(buff.length()-1); // delete the last comma
        return buff.toString();
    }

Upvotes: 1

user1339772
user1339772

Reputation: 803

Are you looking to search for a string in array? If yes, you might want to look at Collections.binarySearch() or Arrays.binarySearch() - but please not that the collections or arrays need to be sorted before doing binary search

Upvotes: 0

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