public class Mapper {

public static void main(String[] args) {
  Map<String, String> map = new HashMap<String, String>();
  map.put("1", "v1");
  map.put("2", "v2");
  map.put("3", "v3");
  
  //第一种：遍历key，再通过key获取对应的value
  System.out.println("通过Map.keySet遍历key和value：");
  for (String key : map.keySet()) {
   System.out.println("key= "+ key + " and value= "http://www.mamicode.com/+ map.get(key));
  }
  

  //第二种：使用Entry,尤其是容量大时
  System.out.println("通过Map.entrySet遍历key和value");
  for (Map.Entry<String, String> entry : map.entrySet()) {
   System.out.println("key= " + entry.getKey() + " and value= "http://www.mamicode.com/+ entry.getValue());
  }


  //第三种:迭代器
  System.out.println("通过Map.entrySet使用iterator遍历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= "http://www.mamicode.com/+ entry.getValue());
  }

  //第四种： 单单遍历value
  System.out.println("通过Map.values()遍历所有的value，但不能遍历key");
  for (String v : map.values()) {
   System.out.println("value= "http://www.mamicode.com/+ v);
  }
 }

}