JAVA学习.JAVA集合类型Map.HashMap&TreeMap，

JAVA学习.JAVA集合类型Map.HashMap&TreeMap，

以下是一张比较简单的介绍图，在具体代码分析之前先大概的了解以下要介绍的内容。

作为key值保存的类对象：

/**
 * 
 */
package MapDemo;

/**
 * @author fshxxxyydys
 *
 */
public class Dog implements Comparable<Dog>{
	
	private String color;
	private Integer age;
	
	
	public Dog() {
		super();
	}
	public Dog(String color, Integer age) {
		super();
		
		// 子类构造方法调用父类构造方法只能放在第一行
		
		this.color = color;
		this.age = age;
	}
	//如果有需要可以根据需要填写不同参数的构造函数
	public String getColor() {
		return color;
	}
	public void setColor(String color) {
		this.color = color;
	}
	public Integer getAge() {
		return age;
	}
	public void setAge(Integer age) {
		this.age = age;
	}
	
	@Override
	public boolean equals(Object obj) {
		
		if(obj == null) return false;
		
		if(obj == this) return true;
		
		if(!(obj instanceof Dog)) return false;
		
		Dog d =(Dog)obj;
		if(this.age.equals(d.age)&&this.color.equals(d.color))
			return true;
		return false;
	}
	@Override
	public int hashCode() {
		
		return  this.color.hashCode() + this.age.hashCode();
	}
	@Override
	public int compareTo(Dog o) {
		//传进来的对象本身就是指定对象类型无需进行判断
		
		
		if(this.age.compareTo(o.age) != 0){
			return this.age.compareTo(o.age);
			
		}
		//先按照年龄来排序
		if(this.color.compareTo(o.color) != 0){
			return this.color.compareTo(o.color);
			
		}
		//再按照颜色来排序
		
		return 0;
		//如果颜色和年龄都相同返回0的就按照相同处理
	}
	@Override
	public String toString() {
		
		return "Color:" + this.color + " Age:" + this.age + ".";
	}
	
}

TreeMap：

/**
 * 
 */
package MapDemo;

import java.util.Set;
import java.util.TreeMap;

/**
 * @author fshxxxyydys
 *
 */
public class TreeMapDemo {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		
		//TreeMap是以TreeSet来进行key管理的Map接口的实现
		//与TreeSet类似，如要使得TreeMap对其key值进行无
		//重复的筛选以及自然顺序排序，则被当做key值得对象
		//必须实现Comparable接口并实现CompareTo方法.
		TreeMap<Dog,String> dogMap = new TreeMap<Dog,String>();
		dogMap.put(new Dog("bule",11),"A");
		dogMap.put(new Dog("bule",12),"B");
		dogMap.put(new Dog("bule",10),"C");
		dogMap.put(new Dog("red",1),"D");
		dogMap.put(new Dog("red",21),"E");
		dogMap.put(new Dog("red",4),"F");
		dogMap.put(new Dog("green",8),"G");
		dogMap.put(new Dog("green",12),"H");
		dogMap.put(new Dog("green",4),"I");
		
		Set<Dog> dogKey = dogMap.keySet();
		//获取dogMap中key的Set值。
		
        for(Dog d:dogKey)
        	System.out.println(d);

	}

}

======================================================================

Result：

Color:red Age:1.
Color:green Age:4.
Color:red Age:4.
Color:green Age:8.
Color:bule Age:10.
Color:bule Age:11.
Color:bule Age:12.
Color:green Age:12.
Color:red Age:21.

======================================================================

HashMap：

/**
 * 
 */
package MapDemo;

import java.util.HashMap;
import java.util.Set;

/**
 * @author fshxxxyydys
 *
 */
public class HashMapDemo {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		
		HashMap<Dog,String> dogMap = new HashMap<Dog,String>();
		
		dogMap.put(new Dog("bule",11),"A");
		dogMap.put(new Dog("bule",12),"B");
		dogMap.put(new Dog("bule",10),"C");
		dogMap.put(new Dog("red",1),"D");
		dogMap.put(new Dog("red",21),"E");
		dogMap.put(new Dog("red",4),"F");
		dogMap.put(new Dog("green",8),"G");
		dogMap.put(new Dog("green",12),"H");
		dogMap.put(new Dog("green",4),"I");
		
	
        for(Dog d:dogMap.keySet())
        	System.out.println(d);
	}

}

======================================================================

Result：

Color:red Age:1.
Color:green Age:4.
Color:red Age:4.
Color:red Age:21.
Color:bule Age:12.
Color:bule Age:11.
Color:bule Age:10.
Color:green Age:12.
Color:green Age:8.

======================================================================

原创出处：http://blog.csdn.net/u012830807