java isempty
字典类isEmpty()方法 (Dictionary Class isEmpty() method)isEmpty() method is available in java.util package.
isEmpty()方法在java.util包中可用。
isEmpty() method is used to check whether this dictionary has the key- pairs value or not.
isEmpty()方法用于检查此字典是否具有密钥对值。
isEmpty() method is a non-static method, it is accessible with the class object and if we try to access the method with the class name then we will get an error.
isEmpty()方法是一种非静态方法，可通过类对象访问，如果尝试使用类名称访问该方法，则会收到错误消息。
isEmpty() method does not throw an exception at the time of checking the empty status of this dictionary.
在检查此字典的空状态时， isEmpty()方法不会引发异常。
Syntax:
句法：
public abstract boolean isEmpty();Parameter(s):
参数：
It does not accept any parameter.
它不接受任何参数。
Return value:
返回值：
The return type of this method is boolean, it returns true when this Dictionary is empty otherwise it returns false.
此方法的返回类型为boolean ，当此Dictionary为空时返回true，否则返回false。
Example:
例：
// Java program is to demonstrate the example of// isEmpty() method of Dictionaryimport java.util.*;public class IsEmptyOfDictionary { public static void main(String[] args) { // Instantiate a Hashtable object Dictionary dictionary = new Hashtable(); // By using put() method is to // add an elements in Hashtable dictionary.put(1, "C"); dictionary.put(2, "C++"); dictionary.put(3, "JAVA"); dictionary.put(4, "PHP"); dictionary.put(5, "SFDC"); // Display Hashtable elements System.out.println("dictionary: " + dictionary); // By using isEmpty() method is to check // whether this Dictionary is empty or not boolean status = dictionary.isEmpty(); // Display status System.out.println("dictionary.isEmpty(): " + status); }}Output
输出量
dictionary: {5=SFDC, 4=PHP, 3=JAVA, 2=C++, 1=C}dictionary.isEmpty(): false翻译自: https://www.includehelp.com/java/dictionary-isempty-method-with-example.aspx
java isempty