java Map集合练习

import java.util.Comparator;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;


public class MapDemo {

	public static void main(String[] args) {
		//HashMethod();
		TreeMethod();
	}
	
	/*
	 * TreeMap中的元素可以排列顺序，构造时用比较器或者实现Comparable接口
	 */
	private static void TreeMethod() {
		Map<Student1,String> map = new TreeMap<Student1,String>(new StuNamComp());
		map.put(new Student1("acc",10),"beijing");
		map.put(new Student1("aaa",12),"wuhan");
		map.put(new Student1("abc",14),"shanghai");
		Set<Student1> keySet = map.keySet();
		for(Iterator<Student1> it = keySet.iterator();it.hasNext();) {
			Student1 stu = it.next();
			System.out.println(stu + map.get(stu));
		}
		
		System.out.println("==============================");
		
		Set<Map.Entry<Student1, String>> entrySet = map.entrySet();
		for(Iterator<Map.Entry<Student1, String>> it = entrySet.iterator();it.hasNext();) {
			Map.Entry<Student1, String> me = it.next();
			System.out.println(me.getKey() + me.getValue());
		}
	}
	
	/*
	 * HashMap中的元素无序(存入和指定的位置不保证一致)，按照哈希表存储
	 */
	private static void HashMethod() {
		Map<Student1,String> map = new HashMap<Student1,String>();
		map.put(new Student1("zhangsan",10),"beijing");
		map.put(new Student1("lisi",12),"wuhan");
		map.put(new Student1("wangwu",14),"shanghai");
		
		Set<Student1> keySet = map.keySet();
		for(Iterator<Student1> it = keySet.iterator();it.hasNext();) {
			Student1 stu = it.next();
			System.out.println(stu + map.get(stu));
		}
		
		System.out.println("==============================");
		
		Set<Map.Entry<Student1, String>> entrySet = map.entrySet();
		for(Iterator<Map.Entry<Student1, String>> it = entrySet.iterator();it.hasNext();) {
			Map.Entry<Student1, String> me = it.next();
			System.out.println(me.getKey() + me.getValue());
		}
	}

}

class StuNamComp implements Comparator<Student1> {

	@Override
	public int compare(Student1 o1, Student1 o2) {
		int num = o1.name.compareTo(o2.name);
		if(num == 0)
			return new Integer(o1.age).compareTo(new Integer(o2.age));
		return num;
	}
	
}

class Student1 implements Comparable<Student1>{
	String name;
	int age;
	Student1(String name,int age) {
		this.name = name;
		this.age = age;
	}
	@Override
	public int hashCode() {
		return this.name.hashCode() * this.age * 20;
	}
	@Override
	public boolean equals(Object obj) {
		if(!(obj instanceof Student1)) {
			throw new ClassCastException("类型错误");
		}
		Student1 stu = (Student1) obj;
		return this.name.equals(stu.name) && this.age == stu.age;
	}
	@Override
	public String toString() {
		return this.name + ".." + age;
	}
	@Override
	public int compareTo(Student1 o) {
		int num = new Integer(this.age).compareTo(new Integer(o.age));
		if(num == 0) {
			return this.name.compareTo(o.name);
		}
		return num;
	}
	
}