The TreeSet of the first season of Java store custom objects and guarantee sorting and uniqueness

In a simple example, the internal process of TreeSet collection storage is described, and it is only guaranteed that the custom objects stored here are perfect.

Requirement: A:
* Natural Sorting, sorted by age from small to large
B
* member variable values are the same as the same element

Custom student classes are given out:

public class Student implements comparable<student> {private String name;private int age;public Student () {super (); }public Student (String name, int age) {super (); this.name = Name;this.age = age;} Public String GetName () {return name;} public void SetName (String name) {this.name = name;} public int getage () {return age;} public void Setage (int.) {this.age = age;} @Overridepublic int CompareTo (Student s) {//return 0;//returns 0 that is a repeating element except for the first root node. Equal not to respond, because for 0, think all do not respond//return 1;//How to get in how to come out. More than 0 right row, 1 is greater than 0 all right row//return-1;//How to get in, how to pour out. Less than 0 left row, 1 less than 0 all left row//seen from above. S is the first, for the root node//What is returned here, in fact, should be based on our sorting rules//According to the order of age, the main condition int num = this.age-s.age;//Secondary condition//age same time, also have to see whether the name is also the same//if the age and name are the same, is the same element int num2 = (num = = 0? this.name.compareTo (s.name): num);//Two-level comparison compare age return num2;}}

The test class was given out:

public class TreeSetDemo2 {public static void main (string[] args) {//Create collection Object treeset<student> ts = new Treeset<stu Dent> ();//create element Student S1 = new Student ("Linqingxia", 27); Student s2 = new Student ("Zhangguorong", 29); Student s3 = new Student ("Wanglihong", 23); Student S4 = new Student ("Linqingxia", 27); Student S5 = new Student ("Liushishi", 22); Student s6 = new Student ("Wuqilong", 40); Student s7 = new Student ("Fengqingy", 22);//add Element Ts.add (S1); Ts.add (S2); Ts.add (S3); Ts.add (S4); Ts.add (S5); Ts.add (S6); Ts.add (S7);//Traverse for (Student s:ts) {System.out.println (S.getname () + "---" + s.getage ());}}

Printing results:

Fengqingy---22
Liushishi---22
Wanglihong---23
Linqingxia---27
Zhangguorong---29
Wuqilong---40

Storing custom objects is actually more of a comparison rule, essentially unchanged.

Beginning of the first season of Java TreeSet Store custom objects and guarantee sorting and uniqueness