java List去掉重复元素的几种方式(小结)

List<String> words= Arrays.asList("a","b","b","c","c","d");
HashSet<String> set=new LinkedHashSet<>(words);
for(String word:set){
   System.out.println(word);
}

//去掉List集合中重复的元素
List<String> words= Arrays.asList("a","b","b","c","c","d");
//方案一：
for(String word:words){
  set.add(word);
}
for(String word:set){
  System.out.println(word);
}

List<String> words= Arrays.asList("a","b","b","c","c","d");
words.stream().distinct().collect(Collectors.toList()).forEach(System.out::println);

List<String> list= new ArrayList<>();
    for (String s:words) {
      if (!list.contains(s)) {
        list.add(s);
      }
    }

public class Student {
  String id;
  String name;
  int age;

  public Student(String id, String name, int age) {
    this.id = id;
    this.name = name;
    this.age = age;
  }

  @Override
  public boolean equals(Object o) {
    if (this == o) return true;
    if (o == null || getClass() != o.getClass()) return false;

    Student student = (Student) o;

    return Objects.equals(id, student.id);
  }

  @Override
  public int hashCode() {
    return id != null ? id.hashCode() : 0;
  }

  @Override
  public String toString() {
    return "Student{" +
        "id='" + id + '\'' +
        ", name='" + name + '\'' +
        ", age=" + age +
        '}';
  }
}