Java遍历Map键、值和获取Map大小的方法示例

importjava.util.HashMap;

importjava.util.Iterator;

importjava.util.Set;

publicclassHashMapTest2

{

 publicstaticvoidmain(String[] args)

 {

 HashMap map =newHashMap();

 map.put("a","aaaa");

 map.put("b","bbbb");

 map.put("c","cccc");

 map.put("d","dddd");

 Set set = map.keySet();

 for(Iterator iter = set.iterator(); iter.hasNext();)

 {

  String key = (String)iter.next();

  String value = (String)map.get(key);

  System.out.println(key+"===="+value);

 }

 }

}

importjava.util.HashMap;

importjava.util.Iterator;

importjava.util.Map;

importjava.util.Set;

publicclassHashMapTest4

{

 publicstaticvoidmain(String[] args)

 {

 HashMap map =newHashMap();

 map.put("a","aa");

 map.put("b","bb");

 map.put("c","cc");

 map.put("d","dd");

 Set set = map.entrySet();

 for(Iterator iter = set.iterator(); iter.hasNext();)

 {

  Map.Entry entry = (Map.Entry)iter.next();

  String key = (String)entry.getKey();

  String value = (String)entry.getValue();

  System.out.println(key +" :"+ value);

 }

 }

}

publicstaticvoidmain(String[] args) {

  Map map =newHashMap();

  map.put("apple","新鲜的苹果");  //向列表中添加数据

  map.put("computer","配置优良的计算机"); //向列表中添加数据

  map.put("book","堆积成山的图书");  //向列表中添加数据

  System.out.println("Map集合大小为："+map.size());

}