字符串 toString 方法

Question

這是帶有toString方法的 class

class Person {

    final String name;
    final String address;
    final String phoneNr;

    Person(String name, String address, String phoneNr) {
        this.name = name;
        this.address = address;
        this.phoneNr = phoneNr;
    }

    @Override
    public String toString() {
        return String.format("%-10s, %-20s, %-10s", name, address, phoneNr);
    }

}

現在我需要在我之前創建的PhoneBookList class 中編寫此方法。 我該怎么做？

Answer 1

在打印任何人 object 時，只需在 Person class 和Phonebooklist列表中覆蓋toString()將使用toString()值

public class Person {

    @Override
    public String toString() {
        return String.format("%-10s, %-20s, %-10s", name, address, phoneNr);
    }
}

public class Phonebooklist {
    public static void main(String[] args) {
        Person person = new Person("name", "address", "000-000-000"); // if you are using constuctor overloading 
        System.out.println(person);
    }
}

, 如果你遍歷 Phonebooklist 中的所有節點並使用 Person 的 toString 格式，你可以這樣做：

  @Override
  public String toString() {
    StringBuilder builder = new StringBuilder();
    Node current = head;

    while (current != null) {
      builder.append(current.person); // this will append person object and use it's toString with this format "%-10s, %-20s, %-10s", name, address, phoneNr
      if (current.next != null) builder.append("\n");
      current = current.next;
    }
    return builder.toString();
  }