Set樹集的排序

Set樹集的排序

定義兩個Item對象，使用Item對象去實現Comparable接口，具體代碼如下：

package com.lj.test;

public  class Item implements Comparable<Item>
{	private String description;
	private int partNumber;
   /*public  Item()
   {
	   
   }*/
   public Item(String aDescription,int aPartNumber)
   {
	   description= aDescription;
	   partNumber=aPartNumber;
   }
	public String getDescription()
	{
		return description;
	}
   public String toString()
   {
	   return"[description="+description+",partNumber="+partNumber+"]";
   }
   public boolean equals(Object otherObject)
   {
	   if(this==otherObject) 
		return true;
	    if(otherObject==null)
		   return false;
	   if(getClass()!=otherObject.getClass())
		   return false;
	   
	   Item other=(Item)otherObject;
	   return description.equals(other.description)&&partNumber==other.partNumber;
	   
	   
   }
   public int hashcode()
   {
	   return 13*description.hashCode()+17*partNumber;
   }
   
   @Override
   public int compareTo(Item other)
   {
	   return partNumber - other.partNumber;
   }
  
}

上面是實現這個接口的工具類，下面是主方法：

package com.lj.test;

import java.util.Comparator;
import java.util.SortedSet;
import java.util.TreeSet;
import com.lj.test.Item;
public class TreeSetTest {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		SortedSet<Item> parts=new TreeSet<Item>();
		
		parts.add( new Item("liujian",1234) );
		parts.add(new Item("tiger",4562));
		parts.add(new Item("Modem",9912));
		System.out.println(parts);
		
		SortedSet<Item> sortByDescription=new TreeSet<Item>(new Comparator<Item>()
				{
					public int compare(Item a,Item b)
					{
						String descrA = a.getDescription();
						String descrB = b.getDescription();
						return descrA.compareTo(descrB);
					}
		}); 
		
		sortByDescription.addAll(parts);
		System.out.println(sortByDescription);
	}

}