Containskey Method -- determines whether the specified key name is included

The containskey method is used to determine whether the map set object contains the specified key name.

Syntax Boolean containskey (Object key)

Return Value: If the map set contains the specified key name, true is returned; otherwise, false is returned.

Parameter: key is the key name object of the map set to be queried.

In this example, the hashmap class is used to create a map set object, add several elements to the set, and call the containskey method to check whether the specified key name is included.

Public static void main (string [] ARGs ){

Map map = new hashmap ();

Map. Put ("apple", "fresh apple"); // Add data to the list

Map. Put ("computer", "computer with excellent configuration"); // Add data to the list

Map. Put ("book", "books stacked into mountains"); // Add data to the list

String key = "book ";

Boolean contains = map. containskey (key );

If (contains ){

System. Out. println ("include key name in map set" + key );

} Else {

System. Out. println ("the key name is not included in the map set" + key );

}

}

Containskey Method -- determines whether the specified key name is included