TreeSet中的两种排序方式

package exercise1;

public class Person implements Comparable{
    private int id;
    private String name;
    public Person(int id, String name) {
        super();
        this.id = id;
        this.name = name;
    }
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String toString() {
        return "Person [id=" + id + ", name=" + name + "]";
    }
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + id;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        return result;
    }
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Person other = (Person) obj;
        if (id != other.id)
            return false;
        if (name == null) {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;
        return true;
    }
    public int compareTo(Object o) {
        if(o instanceof Person){
            Person p=(Person)o;
            return this.name.compareTo(p.name);
        }
        return 0;
    }
    
}











package exercise1;
//TreeSet下的自然排序和定制排序
import java.util.Comparator;
import java.util.Iterator;
import java.util.Set;
import java.util.TreeSet;
import java.util.function.Function;
import java.util.function.ToDoubleFunction;
import java.util.function.ToIntFunction;
import java.util.function.ToLongFunction;

import org.junit.Test;
//定制排序
public class DisOrder {
    @Test
    public void unNature(){
        Comparator com=new Comparator() {

            public int compare(Object o1, Object o2) {
                if(o1 instanceof Person && o2 instanceof Person){
                    Person p1=(Person)o1;
                    Person p2=(Person)o2;
                    return p1.getName().compareTo(p2.getName());

                }
                return 0;
            }

            
        };
        
        Set set=new TreeSet(com);
        set.add(new Person(111,"MM"));
        set.add(new Person(222,"DD"));
        set.add(new Person(333,"GG"));
            
        for(Object obj:set){
            System.out.println(obj);
        }
    }
    //自然排序
    @Test
    public void nature() {
        Set set=new TreeSet();
        set.add("aa");
        set.add("bb");
        set.add("ff");
        set.add("zz");
        for(Object obj:set){
            System.out.println(obj);
        }
            
        
        
    }
}