How to use Java-treeset-Getting Started

In the Java language, the set interface has 3 common implementations HashSet : TreeSet,LinkedHashSet。 TreeSet is a collection of internal elements that can be sorted, using a red-black tree to store internal elements, sorted based on the values of the elements, which is slower than hashset.

TreeSet requires the inner element to implement the comparable interface, because it is sorted according to the CompareTo of the element. Here is a demo:

 Packagecolloections;Importjava.util.LinkedList;ImportJava.util.TreeSet; Public classTreesetdemo { Public Static voidMain (string[] args) {//TODO auto-generated Method StubTreeSet<Person> TreeSet =NewTreeset<person>(); Treeset.add (NewPerson ("Albert", 8)); Treeset.add (NewPerson ("Bob", 5)); Treeset.add (NewPerson ("Bob", 13));  for(person Person:treeset) {System.out.printf (person.tostring ()); }    }}classPersonImplementsComparable<person>{     PublicString name;  Public intAge ;  PublicPerson (String N,inta) {Name=N; Age=A; }         PublicString toString () {returnString.Format ("Name is%s, age is%d%n", name, age); } @Override Public intcompareTo (Person o) {//TODO auto-generated Method Stub        intNamecomp = This. Name.compareto (O.name); return(Namecomp! = 0? Namecomp: ( This. Age-o.age)); }    }

The program output is:

Name is Albert, age is 8
Name is Bob, which is 5
Name is Bob, which is 13

How to use Java-treeset-Getting Started