Java中怎样遍历Map的所有的元素
JDK1.4中
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??? <FONT color=#0000ff>Map map = new HashMap();
??????? Iterator it = map.entrySet().iterator();
??????? while (it.hasNext()) {
??????????? Map.Entry entry = (Map.Entry) it.next();
??????????? Object key = entry.getKey();
??????????? Object value = entry.getValue();
??? }</FONT>
??? Map map = new HashMap();
??????? Iterator it = map.entrySet().iterator();
??????? while (it.hasNext()) {
??????????? Map.Entry entry = (Map.Entry) it.next();
??????????? Object key = entry.getKey();
??????????? Object value = entry.getValue();
??? }JDK1.5中,应用新特性For-Each循环
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??? Map m = new HashMap();
??? for(Object o : map.keySet()){
??????? map.get(o);
??? }
??? Map m = new HashMap();
??? for(Object o : map.keySet()){
??????? map.get(o);
??? }返回的 set 中的每个元素都是一个 Map.Entry 类型。
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??? <FONT color=#0000ff>private Hashtable<String, String> emails = new Hashtable<String, String>();</FONT>
??? private Hashtable<String, String> emails = new Hashtable<String, String>();? 另外 我们可以先把hashMap 转为集合Collection，再迭代输出，不过得到的对象
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???? <FONT color=#0000ff>//方法一: 用entrySet()
?????? Iterator it = emails.entrySet().iterator();
?????? while(it.hasNext()){
??????? Map.Entry m=(Map.Entry)it.next();
??????? logger.info("email-" + m.getKey() + ":" + m.getValue());
?????? }
?????? // 方法二：jdk1.5支持，用entrySet()和For-Each循环()
?????? for (Map.Entry<String, String> m : emails.entrySet()) {
??????? logger.info("email-" + m.getKey() + ":" + m.getValue());
?????? }
?????? // 方法三：用keySet()
?????? Iterator it = emails.keySet().iterator();
?????? while (it.hasNext()){
??????? String key;
??????? key=(String)it.next();
??????? logger.info("email-" + key + ":" + emails.get(key));
?????? }
??? // 方法五：jdk1.5支持，用keySEt()和For-Each循环
??? for(Object m: emails.keySet()){
??????? logger.info("email-" + m+ ":" + emails.get(m));
?????? }
??? </FONT>
???? //方法一: 用entrySet()
?????? Iterator it = emails.entrySet().iterator();
?????? while(it.hasNext()){
??????? Map.Entry m=(Map.Entry)it.next();
??????? logger.info("email-" + m.getKey() + ":" + m.getValue());
?????? }
?????? // 方法二：jdk1.5支持，用entrySet()和For-Each循环()
?????? for (Map.Entry<String, String> m : emails.entrySet()) {
??????? logger.info("email-" + m.getKey() + ":" + m.getValue());
?????? }
?????? // 方法三：用keySet()
?????? Iterator it = emails.keySet().iterator();
?????? while (it.hasNext()){
??????? String key;
??????? key=(String)it.next();
??????? logger.info("email-" + key + ":" + emails.get(key));
?????? }
??? // 方法五：jdk1.5支持，用keySEt()和For-Each循环
??? for(Object m: emails.keySet()){
??????? logger.info("email-" + m+ ":" + emails.get(m));
?????? }
?
???? Map??? aa??? =??? new??? HashMap();????? aa.put("tmp1",??? new??? Object());????? //追加????? 替换用同样的函数.????? aa.remove("temp1");??????????????????????? //删除????? for??? (Iterator??? i??? =??? aa.values().iterator();??? i.hasNext();??? )??? {????????????? Object??? temp??? =??? i.next();????? }????????? //遍历
??? 来个完整的，包含TreeSet的元素内部排序的
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??? public static void main(String[] args) {
?????? ArrayList<String> list = new ArrayList<String>();
?????? HashMap<Object,Object> hash = new HashMap<Object,Object>();
?????? TreeMap<Object,Object> treeMap = new TreeMap<Object,Object>();
?????? list.add("a");
?????? list.add("b");
?????? list.add("c");
?????? hash.put(3, 3);
?????? hash.put(4, 4);
?????? hash.put(5, 5);
?????? hash.put(6, 6);
?????? hash.put(1, 1);
?????? hash.put(2, 2);
?????? treeMap.put(1, 1);
?????? treeMap.put(2, 2);
?????? treeMap.put(3, 3);
?????? treeMap.put(4, 4);
?????? treeMap.put(5, 5);
?????? treeMap.put(6, 6);
?????? //list遍历
?????? for(String m: list){
??????? System.out.println(m);
?????? }
?????? // hashmap entrySet() 遍历
?????? for(Map.Entry<Object,Object> m: hash.entrySet()){
??????? System.out.println(m.getKey()+"---"+m.getValue());
?????? }
?????? //hashmap keySet() 遍历
?????? for(Object m: hash.keySet()){
??????? System.out.println(m+"---"+hash.get(m));
?????? }
?????? // treemap keySet()遍历
?????? for(Object m: treeMap.keySet()){
??????? System.out.println(m+"---"+treeMap.get(m));
?????? }
??? }
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