java中遍歷一個Map

轉自：http://blog.csdn.net/jiafugui/article/details/5182113

//循環遍歷map的方法  
public class CircleMap {  
 public static void main(String[] args) {  
  Map<String, Integer> tempMap = new HashMap<String, Integer>();  
  tempMap.put("a", 1);  
  tempMap.put("b", 2);  
  tempMap.put("c", 3);  
  // JDK1.4中  
  // 遍歷方法一 hashmap entrySet() 遍歷  
  System.out.println("方法一");  
  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,應用新特性For-Each循環  
  // 遍歷方法二  
  System.out.println("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("");  
  
  // 遍歷方法三 hashmap keySet() 遍歷  
  System.out.println("方法三");  
  for (Iterator i = tempMap.keySet().iterator(); i.hasNext();) {  
   Object obj = i.next();  
   System.out.println(obj);// 循環輸出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);// 循環輸出value  
  }  
  System.out.println("");  
  
  // 遍歷方法四 treemap keySet()遍歷  
  System.out.println("方法四");  
  for (Object o : tempMap.keySet()) {  
   System.out.println("key=" + o + " value=" + tempMap.get(o));  
  }  
  System.out.println("11111");  
  
  // java如何遍歷Map <String, ArrayList> map = new HashMap <String,  
  // ArrayList>();  
  System.out  
    .println("java  遍歷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 + "遍歷過程");  
   }  
  }  
  System.out.println("2222");  
  Map<String, List> mapList = new HashMap<String, List>();  
  for (Map.Entry entry : mapList.entrySet()) {  
   String key = entry.getKey().toString();  
   List<String> values = (List) entry.getValue();  
   for (String value : values) {  
    System.out.println(key + " --> " + value);  
   }  
  }  
 }  
}