遍历Map集合的几种方式

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

/**
 * <p>遍历Map集合</p>
 * @author:774346810@qq.com
 * @date:2017-5-30
 */
public class Test {
    public static void main(String[] args) {
        Map<String, String> map = new HashMap<String, String>();
        map.put("username", "yujiwei");
        map.put("password", "12345");
        map.put("address", "hangzhou");
        map.put("love", "编程");
        //1.获取所有的key
        for(String key : map.keySet()){//返回的是map的key值
            String value = map.get(key);//通过key取value
            System.out.println("key = " + key + ",value = " + value);
        }
        
        System.out.println("----------------------------------");
        
        //2.通过map.entrySet的iterator来遍历Map集合
        Iterator<Entry<String, String>> it = map.entrySet().iterator();
        while(it.hasNext()){
            Entry<String, String> entry = it.next();
            System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue());
        }
        
        System.out.println("----------------------------------");
        
        //3.通过Map.Entry来遍历Map集合
        for(Map.Entry<String, String> entry : map.entrySet()){
            System.out.println("key= " + entry.getKey() + " and value= "+ entry.getValue());
        }
    }
}