I have tried as below :
for (Object[] trials: trialSpecs) {
Object[] result= (Object[]) trials;
multiValueMap.put((Integer) result[0], new ArrayList<Integer>());
multiValueMap.get(result[0]).add((Integer)result[1]);
}
But every time the new value is replaced with the old value. I know this is because of new ArrayList<Integer>
I used in the code.
But I am not able to replace this block.
Only put
a new ArrayList()
if one is not already present:
for (Object[] trials: trialSpecs) {
Object[] result= (Object[]) trials;
//Check to see if the key is already in the map:
if(!multiValueMap.containsKey((Integer) result[0]){
multiValueMap.put((Integer) result[0], new ArrayList());
}
multiValueMap.get(result[0]).add((Integer)result[1]);
}
java libraries like Guava and Apache propose the Multimap that does exactly that:
With guava :
Multimap<String, String> mhm = ArrayListMultimap.create();
mhm.put(key, "A");
mhm.put(key, "B");
mhm.put(key, "C");
Collection<String> coll = mhm.get(key);
With apache :
MultiMap mhm = new MultiHashMap();
mhm.put(key, "A");
mhm.put(key, "B");
mhm.put(key, "C");
Collection coll = (Collection) mhm.get(key);
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.