treeset comparator

Using TreeSet and Comparator, write Treesettestinner classes that require elements in the TreeSet "HashSet", "ArrayList", "TreeMap", "HashMap", "TreeSet", " LinkedList "is arranged in ascending and descending order and is implemented separately using anonymous inner classes and static inner classes.Method One:Static In

1. TreeSet guarantee Element uniqueness and comparator ordering principle and code implementation (comparator sort)(1)Student. Java:1 Packagecn.itcast_07;2 3 Public classStudent {4 PrivateString name;5 Private intAge ;6 7 PublicStudent () {8 Super();9 }Ten One PublicStudent (String name,intAge ) { A Super(); - Thi

. compareto (S. Name);} return-1 ;}} Custom Comparator Package Tan; import Java. util. comparator; import Java. util. iterator; import Java. util. treeset; public class treesetdemo {public static void main (string [] ARGs) {// You can input the custom comparator treeset T

TreeSet Conditions Same type Design to sort Comparable is natural (you can modify the case of a class) Comparator is custom (in the case of a class cannot be modified) higher priority Instructions for use: Generally used is the natural sort, but when the class can not be modified to have to use the comparator method, the following demo using two ways. Code Overal

Label: style blog HTTP color ar SP data on 2014 Threeset can sort objects in the set. When a treeset wants to add an object to the set, it will be inserted into the ordered object sequence. Threeset comes with a sorting method that specifies the sorting rules for general data. If you want to specify your own sorting method, You have to rewrite the comparator method for a long time. The following is an

): temp; 57 58 59} 60 61 62} 1 import java. util. comparator; 2 3 import cn. itcast. p1.bean. person; 4 5 public class ComparatorByName implements Comparator {// first by name, then by age 6 7 @ Override 8 public int compare (Object o1, Object o2) {9 Person p1 = (Person) o1; 10 Person p2 = (Person) o2; 11 12 int temp = p1.getName (). compareTo (p2.getName (); 13 14 return temp = 0? P1.getAge ()-p2.getAge

1-Letter Comparator Implementation method code in reverse order Import Java.util.Comparator; Import Java.util.Iterator; Import Java.util.TreeSet; public class TreeSetTest3 {public static void Main (string[] args) { TreeSet set = new TreeSet (new Mycomparator ()) ; Set.add ("C"); Set.add ("A"); Set.add ("B"); Set.add ("E"); Set.add ("F"); Set.a

TreeSet guarantees no duplicate data, also guarantees long (n) Time complexity for Add (), remove (), contains ().ImportJava.util.Comparator;ImportJava.util.TreeSet; Public classMYSETWITHCOMPR { Public Static voidMain (String b[]) {TreeSetNewTreesetNewMYCOMPC ()); Ts.add (NewMyComp ("RED", 1)); System.out.println ("Added"); Ts.add (NewMyComp ("ORANGE", 1)); System.out.println ("Added"); Ts.add (NewMyComp ("BLUE", 1)); System.out.println ("Added"); Ts.

()); Student S1=NewStudent ("1001", "Chen", 67); Student S2=NewStudent ("1001", "Zhang", 17); Student S4=NewStudent ("1003", "Zeng", 47); Student S5=NewStudent ("1004", "Wang", 87); Student S6=NewStudent ("1005", "Chao", 67); Student S3=NewStudent ("1002", "Zhou", 62); Set.add (S1); Set.add (S2); Set.add (S3); Set.add (S4); Set.add (S5); Set.add (S6); for(Java.util.iteratorset.iterator (); It.hasnext ();) {Student s=It.next (); System.out.println (S.getsno ()+

setSize (int size) {this.size = size;} private String color; Private String shape; private int size; Public Game (String materia,string color,string shape,int size) {this.materia=materia; this.color=color; this.shape= Shape This.size=size; @Override public String toString () {return materia+ ">" +color+ ">" +shape+ ">" +size;} /** * Referee class is also called comparator. Enumeration for better control of comparison content * @author Len

: return 0 of compareTo.Features of the TreeSet set: Two sorting methods: Method 1: Make the elements in the set have a comparison, so that the objects added to the TreeSet set must implement the comparable interface to override the compareTo (Object obj) method. This method also becomes the natural or default sorting of elements. (However, if the sorting elements are not written by myself and others do not

above, the TreeSet set will be compared using the compareTo method. In our program, Student with the same name and age will not be added to the set. Next we will consider another scenario. For example, the code above in the company has been written by someone else, and we need another sort method, such as sorting by name. What should we do? We cannot modify the code written by others. At this time, we need to implement the compare method through the

sorting, such as descending, you can use the comparator interface. The interface contains an int compare (t O1, T O2) method, which is used to compare the sizes of O1 and O2.If you need to implement custom sorting, you need to create a TreeSet collection object and provide an comparator object associated with the TreeSet