Java--TreeSet

TreeSet
特點：

• 存儲數據屬於同一類型
• 存儲時按照自然排序
• 存儲自定義對象，1.自定義類要實現Comparable接口，重寫Comparable類2.制定一個比較器

//自帶排序
package chapter09;

import java.util.Set;
import java.util.TreeSet;

public class TreeSetDemo {
	public static void main(String[] args)
	{
		TreeSetDemo t=new TreeSetDemo();
		t.TreeSetTest();
	}
	public void TreeSetTest()
	{
		Set set=new TreeSet();
		set.add("yy");
		set.add("dd");
		set.add("hh");
		for(Object obj:set)
		{
			System.out.println(obj);
		}
	}
}

//實現接口
package chapter09;

import java.util.Set;
import java.util.TreeSet;

public class PersonDemo1 implements Comparable{     //實現接口
	private String name;
	private Integer age;
	//添加get|set方法快捷鍵    ALT+SHIFT+S+R
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
	//添加有參構造函數 快捷鍵  ALT+SHIFT+S+O
	public PersonDemo1(String name, int age) {
		super();
		this.name = name;
		this.age = age;
	}
	//添加構造函數 快捷鍵  ALT+SHIFT+S+C
	public PersonDemo1() {
		super();
		// TODO Auto-generated constructor stub
	}
	//重寫CompareTo方法
	@Override
	public int compareTo(Object o) {
		// TODO Auto-generated method stub
		PersonDemo1 p=(PersonDemo1)o;
		int i= this.age.compareTo(p.age);
		if(i==0)
		{
			return this.name.compareTo(p.name);
		}
		return i;
	}
}
public class TreeSetDemo {
	public static void main(String[] args)
	{
		TreeSetDemo t=new TreeSetDemo();
		t.TreeSetTest();
	}
	public void TreeSetTest()
	{
		Set set=new TreeSet();
		set.add(new PersonDemo1("zs",20));
		set.add(new PersonDemo1("ls",20));
		set.add(new PersonDemo1("ww",28));
		for(Object obj:set)
		{
			PersonDemo1 p=(PersonDemo1)obj;
			System.out.println(p.getName());
		}
	}
}

//制定比較器
package chapter09;

import java.util.Comparator;
import java.util.Set;
import java.util.TreeSet;
public class PersonDemo1 {
	private String name;
	private Integer age;
	//添加get|set方法快捷鍵    ALT+SHIFT+S+R
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public Integer getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
	//添加有參構造函數 快捷鍵  ALT+SHIFT+S+O
	public PersonDemo1(String name, int age) {
		super();
		this.name = name;
		this.age = age;
	}
	//添加構造函數 快捷鍵  ALT+SHIFT+S+C
	public PersonDemo1() {
		super();
		// TODO Auto-generated constructor stub
	}
	
}

public class TreeSetDemo {
	public static void main(String[] args)
	{
		TreeSetDemo t=new TreeSetDemo();
		t.TreeSetTest();
	}
	public void TreeSetTest()
	{
		//制定一個比較器
		Mycomparator mc=new Mycomparator();
		Set set=new TreeSet(mc);       //傳入比較規則
		set.add(new PersonDemo1("zs",20));
		set.add(new PersonDemo1("ls",20));
		set.add(new PersonDemo1("ww",20));
		for(Object obj:set)
		{
			PersonDemo1 p=(PersonDemo1)obj;
			System.out.println(p.getName());
		}
	}
}
class Mycomparator implements Comparator{

	@Override
	public int compare(Object o1, Object o2) {
		// TODO Auto-generated method stub
		PersonDemo1 p1=(PersonDemo1)o1;
		PersonDemo1 p2=(PersonDemo1)o2;
		int i=p1.getAge().compareTo(p2.getAge());
		if(i==0)
		{
			return p1.getName().compareTo(p2.getName());
		}
		return i;
	}
	
}