【Java学习笔记】<集合框架>TreeSet，Comparable，Comparator

public class Person implements Comparable{
    private String name;
    private int age;
    
    public Person(){
        super();
    }
    public Person(String name, int age)
    {
        super();
        this.name = name;
        this.age = age;
    }
    
    
    @Override
    public int hashCode() {
        
        return name.hashCode()+age*27;
    }
    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (!(obj instanceof Person))
            throw new ClassCastException("类型错误");
        
        Person p = (Person) obj;
        
        return this.name.equals(p.name) && this.age ==  p.age;
    }
    @Override
    public String toString() {
        
        return name+":"+age;
    }
    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;
    }
    @Override
    public int compareTo(Object o) {    //先按年龄排，再按姓名排
        
        Person p = (Person)o;
        
        int temp = this.age - p.age;
        
        return temp==0? this.name.compareTo(p.name):temp;
        
        
    }
    
    
}

import java.util.Comparator;

import cn.itcast.p1.bean.Person;

public class ComparatorByName implements Comparator {    //先按姓名排，再按年龄排

    @Override
    public int compare(Object o1, Object o2) {
        Person p1 = (Person)o1;
        Person p2 = (Person)o2;
        
        int temp = p1.getName().compareTo(p2.getName());

        return temp==0?p1.getAge()-p2.getAge() : temp;
    }

}

import java.util.Iterator;
import java.util.TreeSet;

import cn.itcast.p1.bean.Person;
import cn.itcast.p5.comparator.ComparatorByName;

public class TreeSetDemo {

    public static void main(String[] args) {
//        demo1();
        TreeSet ts = new TreeSet(new ComparatorByName()); //添加  new ComparatorByName（），会出现结果一，去除的话 ，出现结果2
                                                             //Comparator 优先于  Comparable

        
        ts.add(new Person("zhangsan",28));
        ts.add(new Person("lisi",21));
        ts.add(new Person("zhouqi",29));
        ts.add(new Person("zhaoliu",25));
        ts.add(new Person("wangwu",24));
        ts.add(new Person("lisi",21));
        ts.add(new Person("zhouqi",29));
        
        Iterator it = ts.iterator();
        
        while (it.hasNext())
        {
            Person p = (Person)it.next();
            
            System.out.println(p);
        }

    }

    public static void demo1() {
        TreeSet ts = new TreeSet();
        
        ts.add("abc");
        ts.add("zaa");
        ts.add("aa");
        ts.add("nba");
        ts.add("cba");
        
        Iterator it = ts.iterator();
        
        while (it.hasNext())
        {
            System.out.println(it.next());
        }
    }

}