JDK1.4中
- <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
- 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。
- <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
- <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
[java] view plaincopyprint?
- 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));
- }
- }
以上内容转自网络:http://blog.youkuaiyun.com/szwangdf/article/details/2544143