Map<Integer,String> map = new HashMap<Integer,String>();for (int i = 0; i < 10000; i++ ){    map.put(i, "thanks");}/*第一种遍历*/Iterator<Map.Entry<Integer,String>> iter = map.entrySet().iterator();while (iter.hasNext()) {    Map.Entry<Integer,String> entry = (Map.Entry<Integer,String>) iter.next();    int key = entry.getKey();    String val = entry.getValue();        System.out.println(key + "=" + val + " ");}/*第二种遍历*/for (Map.Entry<Integer, String> entry : map.entrySet()) {    int key = entry.getKey();    String val = entry.getValue();    System.out.println(key + "=" + val + " ");}/*第三种遍历*/ Iterator<Integer> itr = map.keySet().iterator();while (itr.hasNext()) {     int key = itr.next();     String val = map.get(key);     System.out.println(key + "=" + val + " ");}/*第四种遍历*/for (Integer keyset : map.keySet()) {    int key = keyset.intValue();    String val = map.get(key);    System.out.println(key + "=" + val + " ");}