Je dois convertir un Java HashMap
en une instance de TreeMap
(y compris le contenu de la carte)
HashMap src = ...; TreeMap dest = src.entrySet().stream() .filter( ... ) .collect(Collectors.toMap( ???, ???, ???, TreeMap::new));
Que devrais-je mettre à la place de ???
rendre ce code compilable?
De Collectors.toMap (…) javadoc :
* @param keyMapper a mapping function to produce keys * @param valueMapper a mapping function to produce values * @param mergeFunction a merge function, used to resolve collisions between * values associated with the same key, as supplied * to {@link Map#merge(Object, Object, BiFunction)} * @param mapSupplier a function which returns a new, empty {@code Map} into * which the results will be inserted
Par exemple:
HashMap src = ...; TreeMap dest = src.entrySet().stream() .filter( ... ) .collect(Collectors.toMap(Map.Entry::getKey , Map.Entry::getValue, (a,b) -> a, TreeMap::new));