Java 8并行流并发分组

您可以使用的

of

Collector

Map<String, Set<Person>> groupBy = persons.parallelStream()    .collect(Collector.of(        ConcurrentHashMap::new,        ( map, person ) -> { map.computeIfAbsent(person.name, k -> new HashSet<>()).add(person); map.computeIfAbsent(person.uid, k -> new HashSet<>()).add(person); map.computeIfAbsent(person.phone, k -> new HashSet<>()).add(person);        },        ( a, b ) -> { b.forEach(( key, set ) -> a.computeIfAbsent(key, k -> new HashSet<>()).addAll(set)); return a;        }    ));

正如Holger在评论中所建议的那样，以下方法可能比上述方法更可取：

Map<String, Set<Person>> groupBy = persons.parallelStream()     .collect(HashMap::new, (m, p) -> {          m.computeIfAbsent(p.name, k -> new HashSet<>()).add(p);          m.computeIfAbsent(p.uid, k -> new HashSet<>()).add(p);          m.computeIfAbsent(p.phone, k -> new HashSet<>()).add(p);      }, (a, b) -> b.forEach((key, set) -> {         a.computeIfAbsent(key, k -> new HashSet<>()).addAll(set));     });

它使用的重载

collect