如何在 java 中定义将新项目输入到现有哈希表的方法？

Question

当我想将一个项目添加到预定义的哈希表时，通常很简单。但是每当我想定义一个像 addNewCustomer() 的方法并尝试在该方法内部使用 customerHashtable.put(...); 函数时，它就不起作用。请帮助我定义一个适用于现有哈希表的方法，并让我向其中添加新对象（在本例中为客户）。

下面是代码：

    public static void main(String[] args) {

           Hashtable<Integer, Customer> customerHashtable = new Hashtable<Integer, Customer>();
           customerHashtable.put (1, new Customer("david", "+13035003433", new Address("AR", "77555")));

           Customer customer = new Customer("mark", "13035003433", new Address("AR", "77200"));

           public void addNewCustomers(int key, Customer customer) { 
           customerHashtable.put(key, customer);
           System.out.println(customerHashtable.get(key).toString());
           }
    }

}

Answer 1

您必须将 addNewCutomers() 方法放在 main 方法之外，并为 HashTable 创建一个 class 字段。假设您对静态上下文没问题，它可能看起来像这样：

public class HashtableDemo {

    static Hashtable<Integer, Customer> customerHashtable;

    public static void main(String[] args) {

        customerHashtable = new Hashtable<Integer, Customer>();
        customerHashtable.put (1, new Customer("david", "+13035003433", new Address("AR", "77555")));

        Customer customer = new Customer("mark", "13035003433", new Address("AR", "77200"));
        addNewCustomers(2, customer);
    }

    public static void addNewCustomers(int key, Customer customer) { 
        customerHashtable.put(key, customer);
        System.out.println(customerHashtable.get(key).toString());
    }
}

如何在 java 中定义将新项目输入到现有哈希表的方法？

How to define a method to enter a new item to an existing hashtable in java?

java

methods

hash

hashtable