Map接口-HashMap常用方法

package sxt.gaoqi.container;

import java.util.HashMap;
import java.util.Map;

public class TestMap
{
	public static void main(String[] args)
	{
		Map<Integer, String> map = new HashMap<>();
		
		map.put(1, "one");
		map.put(2, "two");
		map.put(3, "three");
		
		System.out.println(map.get(2));
		
		System.out.println(map.size());
		System.out.println(map.isEmpty());
		System.out.println(map.containsKey(2));
		System.out.println(map.containsValue("two"));
		
		Map<Integer, String> map2 = new HashMap<>();
		map2.put(4, "四");
		map2.put(5, "五");
		
		map.putAll(map2);
		
		System.out.println(map);
		
		//map中鍵不能重複！如果重複（是否重複是根據equals來判斷的），則新的覆蓋舊的
		map.put(5, "66");
		System.out.println(map);
	}
}