Sorting List<> in Java

Question

I have a List<Person>. Person's attributes are String name, String secondName, int phoneNum.

How can I sort this List by the String property secondName?

I've tried moving into another List<String> the data from the previous list moving secondName to the first position, then applying Collection.sort and creating other List<Person> with the data of the List sorted but its too complicated.

[Sorting an ArrayList of objects using a custom sorting order](//stackoverflow.com/q/1814095) — 001, Jan 09 '20 at 18:23
Does this answer your question? [Sorting an ArrayList of objects using a custom sorting order](https://stackoverflow.com/questions/1814095/sorting-an-arraylist-of-objects-using-a-custom-sorting-order) — Muralidharan.rade, Jan 09 '20 at 18:28

pwdz · Answer 1 · 2020-01-09T19:15:02.263

3

Java 8 introduced a sort method in the List interface which can use a comparator.

If you have a getter for secondName you can do this:

 myList.sort(Comparator.comparing(Person::getSecondName));

If you don't have a getter use this one:

myList.sort(Comparator.comparing((person)->(person.secondName)));

for more ways and answers: link

edited Jan 09 '20 at 19:15

answered Jan 09 '20 at 18:42

pwdz

49
5

The OP didn't mention any getters. – WJS Jan 09 '20 at 18:59
@WJS true. thanks for saying – pwdz Jan 09 '20 at 19:13

score 1 · Answer 2 · answered Jan 09 '20 at 18:44

Lets assume here is your Pojo Class Person.

class Person{
String name;
String secondName;
//Getter and setters
}

Then sort the list by java collection API itself.

java.util.Collections.sort(personList, new Comparator<Person>() {
        @Override
        public int compare(Person o1, Person o2) {
            return o1.getSecondName().compareToIgnoreCase(o2.getSecondName());
        }
        });

Sorting List<> in Java

2 Answers2