在Java中对ArrayList wrt日期进行排序

Question

I am trying to sort ArrayList wrt termDate ArrayList contains firstName,lastName,email,startDate,termDate

Dates can be either empty or null. I have to compare accordingly and put all the null/empty date values at the end.

Collections.sort(usersList, new Comparator<User>() {
                public int compare(User o1, User o2) {
                    if(o1.getTermDate() == null && o2.getTermDate() == null)
                        return 0; //They are both null, both equal
                    if(o1.getTermDate() == null && o2.getTermDate() != null)
                        return -1; // The first is null and the second is not, return the first as lower than the second
                    if(o1.getTermDate() != null && o2.getTermDate() == null)
                        return 1; //The first is not null and the second is, return the first as higher than the second
                    else
                        return o1.getTermDate().compare(o2.getTermDate()); //Return the actual comparison
                }
            });

It is not compiling compare method.

Please guide.

Answer 1

You should change return o1.getTermDate().compare(o2.getTermDate()); to return o1.getTermDate().compareTo(o2.getTermDate()); Because the class java.util.Date; has not method called compare .