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); } } }
原文：http://www.cnblogs.com/zyzcj/p/5309536.html