判断Map集合中是否存在某一个key

转载地址：https://www.cnblogs.com/yang-xiansen/p/10563284.html

方法一：
Map<String,String> hashmp = ne HashMap();
hashmp.put("aa", "111");
hashmap.containsKey("xxx");


方法二：keySet()
HashMap hashmp = ne HashMap();
hashmp.put("aa", "111");
Set set = hashmp.keySet();
Iterator iter = set.iterator();
while (iter.hasNext()) {
String key = (String) iter.next();
// printkey
}
// traverse
for (String key : list.get(pos).keySet() ) {
myKey = key;
}


方法三：entrySet()
HashMap map;
Iterator i = map.entrySet().iterator();
while (i.hasNext()) {
Object obj = i.next();
String key = obj.toString();
}
// or
while (i.hasNext()) {
Entry entry = (java.util.Map.Entry)it.next();
entry.getkey();
entry.getValue();
}

方法一：Map<String,String> hashmp = ne HashMap();hashmp.put("aa", "111");hashmap.containsKey("xxx");

方法二：keySet()HashMap hashmp = ne HashMap();hashmp.put("aa", "111");Set set = hashmp.keySet();Iterator iter = set.iterator();while (iter.hasNext()) {String key = (String) iter.next();// printkey}// traversefor (String key : list.get(pos).keySet() ) {myKey = key;}

方法三：entrySet()HashMap map;Iterator i = map.entrySet().iterator();while (i.hasNext()) {Object obj = i.next();String key = obj.toString();}// orwhile (i.hasNext()) {Entry entry = (java.util.Map.Entry)it.next();entry.getkey();entry.getValue();}