Java遍歷Map集合的幾種方式

遍歷Map集合的幾種方式

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

public class Mmmmmap {
	public static void main(String[] args){
		HashMap<String> map = new HashMap<String>();
		map.put("name", "xzy");
		map.put("age", "22");
		map.put("add", "nb");

		// 方法一、 通過key 獲取 value
		for (String key : map.keySet()) {
			System.out.println("key= "+ key + " and value= " + map.get(key));
			....
  		}

		// 方法二、通過迭代器iterator遍歷key 和 value
		Iterator<Map.Entry<String, String>> it = map.entrySet().iterator();
  		while (it.hasNext()) {
   			Map.Entry<String, String> entry = it.next();
   			System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue());
   			....
		}


		// 方法三、通過map專用的entrySet 去遍歷map
		for (Map.Entry<String, String> entry : map.entrySet()) {
   			System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue());
   			....
  		}


		// 方法四、只獲取values
		for (String v : map.values()) {
		    System.out.println("value= " + v);
		    ....
		}

	}	


}