MapAppTest.java

package javamap;

import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.TreeMap;

public class MapAppTest {
	/**
	 * @Create on Nov 9, 2009 by lrm
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		MapAppTest.noOrder();
		MapAppTest.hasOrder();
		MapAppTest.likedHashMap();
	}

	public static void noOrder() {

		System.out.println("------无序（随机输出------");
		Map map = new HashMap();
		map.put("1", "Level 1");
		map.put("2", "Level 2");
		map.put("3", "Level 3");
		map.put("4", "Level 4");
		map.put("F", "Level F");
		map.put("Q", "Level Q");
		Iterator it = map.entrySet().iterator();
		while (it.hasNext()) {
			Map.Entry e = (Map.Entry) it.next();
			System.out.println("Key: " + e.getKey() + ";   Value: "
					+ e.getValue());
		}
	}

	// 有序(默认排序，不能指定)
	public static void hasOrder() {
		System.out.println("------有序（但是按默认顺充，不能指定）------");
		Map map = new TreeMap();
		map.put("F", "Level F");
		map.put("7", "Level 1");
		map.put("8", "Level 2");
		map.put("4", "Level 3");
		map.put("4", "Level 4");
		map.put("Q", "Level Q");
		map.put("E", "Level E");
		Iterator it = map.entrySet().iterator();
		while (it.hasNext()) {
			Map.Entry e = (Map.Entry) it.next();
			System.out.println("Key: " + e.getKey() + ";   Value: "
					+ e.getValue());
		}
	}

	public static void likedHashMap() {
		System.out.println("------有序（根据输入的顺序输出）------");
		LinkedHashMap map = new LinkedHashMap(7, 1f, true) {
			protected boolean removeEldestEntry(Map.Entry eldest) {
				return this.size() > 5;
			}
		};
		map.put("F", "Level F");
		map.put("7", "Level 1");
		map.put("8", "Level 2");
		map.put("4", "Level 3");
		map.put("4", "Level 4");
		map.put("Q", "Level Q");
		map.put("E", "Level E");
		map.get("E");
		map.get("F");
		Iterator it = map.entrySet().iterator();
		while (it.hasNext()) {
			Map.Entry e = (Map.Entry) it.next();
			System.out.println("Key: " + e.getKey() + ";   Value: "
					+ e.getValue());
		}
	}
}