java treeset 排序 浅谈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);
    }
      
    
    
  }
}