pg数据库插入数据的时候，进行数据去重

List<User> dataList  = new  ArrayList<User>
  //数据去重（username  + age   + obsTime）
  // 根据这3个字段进行去重
 Set<User> set = new HashSet<>(dataList);
   List<User> newList = new ArrayList<>(set);

然后将这个list  插入到数据库

public   class  User{

private  String  username;

private Date obsTime;

private  String  password;

private  String  age ;

private  String  class;

  @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        User   user= (User) o;
        return username.equals(user.username) && obsTime.getTime() == user.obsTime.getTime() && age == user.age ();
    }

    @Override
    public int hashCode() {
        return Objects.hash(username, age, obsTime);
    }




}