遍历HashMap取出所有的Key和Value

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public class HashMapSet { public static void main(String [] ags){  Map m = new HashMap();  m.put("w", "111");  m.put("h", "222");  m.put("g", "333");  m.put("d", "444");  m.put("s", "555");    System.out.println("--------------------遍历key和value----------------------");  //entrySet()方法用于在获得关键字的同时也获得值该方法返回一个Map.Entry实例后的对象集  //该方法和keySet()方法相比 keySet每次只获得关键字 获得关键字以后 再返回获得值 比较麻烦  //同时Map.Entry方法 也提供了两个方法 getKey();getValue()  for(Iterator iter = m.entrySet().iterator();iter.hasNext();){    Map.Entry element = (Map.Entry)iter.next();    Object strKey = element.getKey();    Object strValue = element.getValue();        System.out.println(strKey+"/"+strValue);  }     System.out.println();  System.out.println("--------------------遍历整个HashMap----------------------");  //Collection 类是Map和Set接口的父类  Collection objs = m.entrySet();  for (Iterator iterator=objs.iterator(); iterator.hasNext();){   Object obj = iterator.next();   System.out.println(obj);  }     System.out.println();  System.out.println("--------------------遍历HashMap的key----------------------");  Collection keys = m.keySet();  for (Iterator iterator=keys.iterator(); iterator.hasNext();){   Object key = iterator.next();   System.out.println(key);  }     System.out.println();  System.out.println("--------------------遍历HashMap的value----------------------");  Collection values = m.values();  for (Iterator iterator=values.iterator(); iterator.hasNext();){   Object value = iterator.next();   System.out.println(value);  } }}
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