遍历Map

ackagecom.jackey.topic;

importjava.util.ArrayList;

importjava.util.HashMap;

importjava.util.Iterator;

importjava.util.List;

importjava.util.Map;

importjava.util.Set;

//循环遍历map的方法

publicclassCircleMap {

 publicstaticvoidmain(String[] args) {

  Map<String, Integer> tempMap = newHashMap<String, Integer>();

  tempMap.put("a", 1);

  tempMap.put("b", 2);

  tempMap.put("c", 3);

  // JDK1.4中

  // 遍历方法一 hashmap entrySet() 遍历

  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,应用新特性For-Each循环

  // 遍历方法二

  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("");

  // 遍历方法三 hashmap keySet() 遍历

  System.out.println("方法三");

  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

  }

  System.out.println("");

  // 遍历方法四 treemap keySet()遍历

  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如何遍历Map <String, ArrayList> map = new HashMap <String,

  // ArrayList>();

  System.out

    .println("java  遍历Map <String, ArrayList> map = newHashMap

<String, ArrayList>();");

  Map<String, ArrayList> map = newHashMap<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 + "遍历过程");

   }

  }

  System.out.println("2222");

  Map<String, List> mapList = newHashMap<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);

   }

  }

 }