遍历Map方式

package m.q;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;

/**
 * @author Administrator
 * 
 */
public class MapTest {

	public static void main(String[] args) {

		Map<String, String> map = new HashMap<>();
		map.put("1", "a");
		map.put("2", "b");
		map.put("3", "c");
		a(map);
		b(map);
		c(map);
		d(map);
	}

	/**
	 * @param map
	 *            第一种:二次取值 Map.keySet() 返回此映射中包含的键的 Set 视图。
	 */
	public static void a(Map<String, String> map) {
		for (String key : map.keySet()) {
			System.out.println("a: key:" + key + " value:" + map.get(key));
		}
	}

	/**
	 * @param map
	 *            entrySet() 返回此映射中包含的映射关系的 Set 视图
	 */
	public static void b(Map<String, String> map) {
		Iterator<Entry<String, String>> iterator = map.entrySet().iterator();
		while (iterator.hasNext()) {
			Entry<String, String> entry = iterator.next();
			System.out.println("b: key:" + entry.getKey() + " value:"
					+ entry.getValue());
		}

	}

	/**
	 * @param map
	 *            Map.entrySet()遍历key和value
	 */
	public static void c(Map<String, String> map) {
		for (Entry<String, String> entry : map.entrySet()) {
			System.out.println("c: key:" + entry.getKey() + " value:"
					+ entry.getValue());
		}
	}

	/**
	 * @param map
	 *            Map.value()遍历value(不能遍历key)
	 */
	public static void d(Map<String, String> map) {
		for (String v : map.values()) {
			System.out.println("d: key:" + "" + " value:" + v);
		}
	}

}