Question

调用setCustomer方法时遇到问题。编码如下：

public class Customer {

    public int customerID = 001;
    public String name ="name required";
    public String address ="address required";
    public String email ="email required";

    public void setCustomer(int custID, String nm , String add ){
    }

    public void setCustomer(int custID, String nm , String add , String em){
    }

    public void displayCustomer(){

        System.out.println("Customer ID: " +customerID);
        System.out.println("Customer Name: " +name);
        System.out.println("Customer Address: " +address);
        System.out.println("Customer Email: " +email);

    }//end of display method

}//end of class


public class CustomerTest {

    public static void main(String[] args) {
        Customer c1 = new Customer();
        Customer c2 = new Customer();
        c1.setCustomer(002, "ishihi", "alalalla2");
        c2.setCustomer(003, "tututu", "kikiki","rans@g.com");
        c1.displayCustomer();
        c2.displayCustomer();
    }
}

我得到的输出是：

Customer ID: 1
Customer Name: name required
Customer Address: address required
Customer Email: email required
Customer ID: 1
Customer Name: name required
Customer Address: address required
Customer Email: email required

我想在主函数中显示我为c1和c2设置的内容，但它仍然如上所示。

Answer 1

您的setCustomer方法为空

public void setCustomer(int custID, String nm , String add ){
}

public void setCustomer(int custID, String nm , String add , String em){
}

实施您想要的行为。

Answer 2

public void setCustomer(int custID, String nm , String add ){ }

这个方法做得不多，毕竟你的方法体是{}，所以毫无意外的是它没有效果。编程不会通过魔法改变对象的状态 - 您必须编写代码才能执行此操作。使用设置对象的字段的代码填写{}，您将看到魔法变为现实。

Answer 3

您需要在方法中实际设置所有类字段。它们目前是空的，不做任何事情。

public void setCustomer(int custID, String nm , String add ){
    customerID = custID;
    name = nm;
    address = add;
}

public void setCustomer(int custID, String nm , String add , String em){
    customerID = custID;
    name = nm;
    address = add;
    email = em;
}

在main中，使用这些方法。您目前没有给他们打电话：

public static void main(String[] args) {
    Customer c1 = new Customer();
    c1.setCustomer(1, "name1", "address1", "email1");
    Customer c2 = new Customer();
    c1.setCustomer(2, "name2", "address2", "email2");
}

Java方法覆盖问题

3 个答案: