为什么ContactNode稍后会导致我的codeEntry出现问题？

Question

我不断从编译器收到此消息，这是我的代码，它应该打印一个人姓，电话号码和生日。我应该使用类Contact节点来使程序正常工作，但我真的不明白它是如何工作的。这部分应该在联系节点之前，但由于某种原因我不能将它粘贴在输入代码行上： ＆＃34;

import java.util.Scanner;

public class ContactList {

public static void main（String [] args）{

  Scanner scnr = new Scanner(System.in);
  String fullName;
  String phoneNumber;
  String birthDay;   

  ContactNode contactEntry1;
  ContactNode contactEntry2;
  ContactNode contactEntry3;
  ContactNode currContactEntry;

  System.out.println("Person 1");
  System.out.println("Enter name:");
  fullName = scnr.nextLine();

  System.out.println("Enter phone number:");
  phoneNumber = scnr.nextLine();

  System.out.println("Enter birthday:");
  birthDay = scnr.nextLine();

  System.out.println("You entered: " + fullName + ", " + phoneNumber + ", " + birthDay);

  //First contact node (head of list)
  contactEntry1 = new ContactNode(fullName, phoneNumber, birthDay);

  System.out.println("");
  System.out.println("Person 2");
  System.out.println("Enter name:");
  fullName = scnr.nextLine();

  System.out.println("Enter phone number:");
  phoneNumber = scnr.nextLine();

  System.out.println("Enter birthday: ");
  birthDay = scnr.nextLine();

  System.out.println("You entered: " + fullName + ", " + phoneNumber + ", " + birthDay);

  contactEntry2 = new ContactNode(fullName, phoneNumber , birthDay);
  contactEntry1.insertAfter(contactEntry2);

  System.out.println("");
  System.out.println("Person 3");
  System.out.println("Enter name:");
  fullName = scnr.nextLine();

  System.out.println("Enter phone number:");
  phoneNumber = scnr.nextLine();

  System.out.println("Enter birthday:");
  birthDay  = scnr.nextLine();

  System.out.println("You entered: " + fullName + ", " + phoneNumber);

  contactEntry3 = new ContactNode(fullName, phoneNumber);
  contactEntry2.insertAfter(contactEntry3);

  System.out.println("");
  System.out.println("CONTACT LIST");

  currContactEntry = contactEntry1;

  while (currContactEntry != null) {
     currContactEntry.printContactNode();
     currContactEntry = currContactEntry.getNext();
     System.out.println("");
  }

  return;

}
}

/tmp/java_abImvG/ContactList.java:10: error: cannot find symbol ContactNode contactEntry1; ^ symbol: class ContactNode location: class ContactList /tmp/java_abImvG/ContactList.java:11: error: cannot find symbol ContactNode contactEntry2; ^ symbol: class ContactNode location: class ContactList /tmp/java_abImvG/ContactList.java:12: error: cannot find symbol ContactNode contactEntry3; ^ symbol: class ContactNode location: class ContactList /tmp/java_abImvG/ContactList.java:13: error: cannot find symbol ContactNode currContactEntry; ^ symbol: class ContactNode location: class ContactList /tmp/java_abImvG/ContactList.java:28: error: cannot find symbol contactEntry1 = new ContactNode(fullName, phoneNumber, birthDay); ^ symbol: class ContactNode location: class ContactList /tmp/java_abImvG/ContactList.java:43: error: cannot find symbol contactEntry2 = new ContactNode(fullName, phoneNumber , birthDay); ^ symbol: class ContactNode location: class ContactList /tmp/java_abImvG/ContactList.java:59: error: cannot find symbol contactEntry3 = new ContactNode(fullName, phoneNumber); ^ symbol: class ContactNode location: class ContactList 7 errors