利用HashSet
創建了一個HashSet用于存儲唯一的字段值，并創建了一個新的列表uniqueList用于存儲去重后的對象。遍歷原始列表時，如果字段值未在HashSet中出現過，則將其添加到HashSet和uniqueList中。
List<Person> originalList = new ArrayList<>();originalList.add(new Person(1, "Alice"));originalList.add(new Person(2, "Bob"));originalList.add(new Person(3, "Alice"));originalList.add(new Person(4, "Charlie"));originalList.add(new Person(5, "Alice"));HashSet<String> uniqueSet = new HashSet<>();List<Person> uniqueList = new ArrayList<>();for (Person person : originalList) {if (uniqueSet.add(person.getName())) {uniqueList.add(person);}}System.out.println(uniqueList);
利用Stream
List<Person> originalList = new ArrayList<>();originalList.add(new Person(1, "Alice"));originalList.add(new Person(2, "Bob"));originalList.add(new Person(3, "Alice"));originalList.add(new Person(4, "Charlie"));originalList.add(new Person(5, "Alice"));List<Person> uniqueList = originalList.stream().collect(Collectors.toMap(Person::getName, person -> person, (p1, p2) -> p1)).values().stream().collect(Collectors.toList());System.out.println(uniqueList);
List<Person> originalList = new ArrayList<>();originalList.add(new Person(1, "Alice"));originalList.add(new Person(2, "Bob"));originalList.add(new Person(3, "Alice"));originalList.add(new Person(4, "Charlie"));originalList.add(new Person(5, "Alice"));List<Person> list = new ArrayList<>(originalList);list = list.stream().collect(Collectors.collectingAndThen(Collectors.toCollection(() -> new TreeSet<>(Comparator.comparing(Person::getName))), ArrayList::new));System.out.println(uniqueList);
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