CODEWITHSUNDEEP
javasortingarraylist
João Silvério
João Silvério

Reputation: 21

How to sort an ArrayList of users by userNumber

I am doing an Access Control System and I have an ArrayList of User objects that contains a user number and other things. Here is a printed example of the list:

1;258;Pedro Pereira
2;3579;Pedro Miguens;A DEMO para LIC está pronta
9;391;João Silvério;Bem Vindo Criador
6;1234;joao
4;391;Miguel Fernandes;Telefonar ao João Manuel

How do I sort the ArrayList so that the userList is ordered without having to write the full code?

Upvotes: 0

Views: 239

Answers (2)

Mehdi
Mehdi

Reputation: 1096

You need to implement Comparable interface for your user class and implement its compareTo method. You have option to choose which field or combination of fields you want to be as your key for sorting.

Next whenever you want to sort your list, you can use Collection.sort(userList).

Upvotes: 0

riddle_me_this
riddle_me_this

Reputation: 9155

In Java 8, it could be something like:

Collections.sort(userList, (user1, user2) -> user1.getId() - user2.getId());

assuming you have an ArrayList of User beans called userList, each with a property called id.

Upvotes: 2

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