用双向链表作数据结构，用java语言编写一个通讯录管理系统，本系统应完成一下几方面的功能： 1)输入信息——enter(); 2)显示信息———display( ); 3)查找以姓名作为关键字 ———search( ); 4)删除信息———delete( ); 5)存盘———save ( ); 6)装入———load( ) ; 设计要求： 1)每条信息至包含 ：姓名（NAME ）街道（STREET）城市（CITY）邮编（EIP）国家（STATE）几项 2)作为一个完整的系统，应具有友好的界面和较强的容错能力，上机能正常运行

以下是一个使用双向链表作为数据结构的通讯录管理系统的 Java 代码，包括输入信息、显示信息、查找、删除、存盘和装入等功能：

import java.io.*;
import java.util.Scanner;

class Contact {
    String name;
    String street;
    String city;
    String zip;
    String state;

    Contact prev;
    Contact next;

    public Contact(String name, String street, String city, String zip, String state) {
        this.name = name;
        this.street = street;
        this.city = city;
        this.zip = zip;
        this.state = state;
        prev = null;
        next = null;
    }

    public void display() {
        System.out.println("Name: " + name);
        System.out.println("Street: " + street);
        System.out.println("City: " + city);
        System.out.println("Zip: " + zip);
        System.out.println("State: " + state);
    }
}

class ContactList {
    Contact head;
    Contact tail;

    public ContactList() {
        head = null;
        tail = null;
    }

    public void enter() {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter name: ");
        String name = sc.nextLine();
        System.out.print("Enter street: ");
        String street = sc.nextLine();
        System.out.print("Enter city: ");
        String city = sc.nextLine();
        System.out.print("Enter zip: ");
        String zip = sc.nextLine();
        System.out.print("Enter state: ");
        String state = sc.nextLine();

        Contact newContact = new Contact(name, street, city, zip, state);
        if (head == null) {
            head = newContact;
            tail = newContact;
        } else {
            tail.next = newContact;
            newContact.prev = tail;
            tail = newContact;
        }
    }

    public void display() {
        Contact current = head;
        while (current != null) {
            current.display();
            current = current.next;
        }
    }

    public void search() {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter name to search: ");
        String name = sc.nextLine();
        Contact current = head;
        boolean found = false;
        while (current != null) {
            if (current.name.equalsIgnoreCase(name)) {
                current.display();
                found = true;
            }
            current = current.next;
        }
        if (!found) {
            System.out.println("No contact found with name " + name);
        }
    }

    public void delete() {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter name to delete: ");
        String name = sc.nextLine();
        Contact current = head;
        boolean found = false;
        while (current != null) {
            if (current.name.equalsIgnoreCase(name)) {
                found = true;
                if (current == head) {
                    head = current.next;
                    if (head != null) {
                        head.prev = null;
                    }
                } else if (current == tail) {
                    tail = current.prev;
                    if (tail != null) {
                        tail.next = null;
                    }
                } else {
                    current.prev.next = current.next;
                    current.next.prev = current.prev;
                }
                System.out.println("Contact deleted.");
                break;
            }
            current = current.next;
        }
        if (!found) {
            System.out.println("No contact found with name " + name);
        }
    }

    public void save() {
        try {
            FileOutputStream fos = new FileOutputStream("contacts.dat");
            ObjectOutputStream oos = new ObjectOutputStream(fos);
            oos.writeObject(head);
            oos.close();
            fos.close();
            System.out.println("Contacts saved to file.");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public void load() {
        try {
            FileInputStream fis = new FileInputStream("contacts.dat");
            ObjectInputStream ois = new ObjectInputStream(fis);
            head = (Contact) ois.readObject();
            ois.close();
            fis.close();
            System.out.println("Contacts loaded from file.");
        } catch (IOException | ClassNotFoundException e) {
            e.printStackTrace();
        }
    }
}

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        ContactList list = new ContactList();
        while (true) {
            System.out.println("1. Enter contact");
            System.out.println("2. Display contacts");
            System.out.println("3. Search contact");
            System.out.println("4. Delete contact");
            System.out.println("5. Save contacts to file");
            System.out.println("6. Load contacts from file");
            System.out.println("0. Exit");
            System.out.print("Enter your choice: ");
            int choice = sc.nextInt();
            sc.nextLine(); // consume newline

            switch (choice) {
                case 1:
                    list.enter();
                    break;
                case 2:
                    list.display();
                    break;
                case 3:
                    list.search();
                    break;
                case 4:
                    list.delete();
                    break;
                case 5:
                    list.save();
                    break;
                case 6:
                    list.load();
                    break;
                case 0:
                    System.exit(0);
                    break;
                default:
                    System.out.println("Invalid choice.");
            }
        }
    }
}

在这个实现中，`Contact` 类表示一个联系人，包含姓名、街道、城市、邮编和国家等信息，以及前后指针。`ContactList` 类表示一个联系人列表，维护头尾指针，并提供输入、显示、查找、删除、存盘和装入等方法。主函数提供了一个菜单，用户可以选择不同的功能。通讯录的信息可以保存到文件中，也可以从文件中装入。