Map的5种遍历方法

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转载最新推荐文章于 2026-07-10 10:11:42 发布 233 阅读 AI 写同款· GEO 优化 ›

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//循环遍历map的方法  
public class MapF {  
 public static void main(String[] args) {  
  Map<String, Integer> tempMap = new HashMap<String, Integer>();  
  tempMap.put("a","12");  
  tempMap.put("b","34");  
  tempMap.put("c","56");  
  // JDK1.4中  
  // 遍历方法一 hashmap entrySet() 遍历  
  Iterator it = tempMap.entrySet().iterator();  
  while (it.hasNext()) {  
   Map.Entry entry = (Map.Entry) it.next();  
   Object key = entry.getKey();  
   Object value = entry.getValue();  
   System.out.println("key=" + key + " value=" + value);  
  }  
  System.out.println("");  
  // JDK1.5中,应用新特性For-Each循环  
  // 遍历方法二  
  for (Map.Entry<String, Integer> entry : tempMap.entrySet()) {  
   String key = entry.getKey().toString();  
   String value = entry.getValue().toString();  
   System.out.println("key=" + key + " value=" + value);  
  }  
  System.out.println("");  
  // 遍历方法三 hashmap keySet() 遍历  
  for (Iterator i = tempMap.keySet().iterator(); i.hasNext();) {  
   Object obj = i.next();  
   System.out.println(obj);// 循环输出key  
   System.out.println("key=" + obj + " value=" + tempMap.get(obj));  
  }  
  for (Iterator i = tempMap.values().iterator(); i.hasNext();) {  
   Object obj = i.next();  
   System.out.println(obj);// 循环输出value  
  }  
  // 遍历方法四 treemap keySet()遍历  
  for (Object o : tempMap.keySet()) {  
   System.out.println("key=" + o + " value=" + tempMap.get(o));  
  }  
  System.out.println("11111");  
  // java如何遍历Map <String, ArrayList> map = new HashMap <String,  
  // ArrayList>();  
  System.out.println("java  遍历Map <String, ArrayList> map = new HashMap<String, ArrayList>();");  
  Map<String, ArrayList> map = new HashMap<String, ArrayList>();  
  Set<String> keys = map.keySet();  
  Iterator<String> iterator = keys.iterator();  
  while (iterator.hasNext()) {  
   String key = iterator.next();  
   ArrayList arrayList = map.get(key);  
   for (Object o : arrayList) {  
    System.out.println(o);  
   }  
  }  
  Map<String, List> map = new HashMap<String, List>();  
  for (Map.Entry entry : map.entrySet()) {  
   String key = entry.getKey().toString();  
   List<String> list= (List) entry.getValue();  
   for (String value : list) {  
    System.out.println(key + "====" + value);  
   }  
  }  
 }  
}

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