编写手机类（MobilePhone），含有type（型号，String类型）、price（价格，int类型）属性，在链表中添加n个手机对象（从键盘输入），并实现以下操作：1）按手机价格从低到高输出手机信息。2）实现根据型号查找手机信息。3）查找某个价格区间内的手机（如2000~3000

下面是一个可能的实现：

import java.util.Scanner;

class MobilePhone {
    private String type;
    private int price;

    public MobilePhone(String type, int price) {
        this.type = type;
        this.price = price;
    }

    public String getType() {
        return type;
    }

    public int getPrice() {
        return price;
    }

    public String toString() {
        return type + " " + price;
    }
}

class Node {
    public MobilePhone data;
    public Node next;

    public Node(MobilePhone data) {
        this.data = data;
        this.next = null;
    }
}

class LinkedList {
    private Node head;

    public void add(MobilePhone data) {
        Node newNode = new Node(data);
        if (head == null) {
            head = newNode;
        } else {
            Node current = head;
            while (current.next != null) {
                current = current.next;
            }
            current.next = newNode;
        }
    }

    public void print() {
        Node current = head;
        while (current != null) {
            System.out.println(current.data);
            current = current.next;
        }
    }

    public MobilePhone findByType(String type) {
        Node current = head;
        while (current != null) {
            if (current.data.getType().equals(type)) {
                return current.data;
            }
            current = current.next;
        }
        return null;
    }

    public void findByPrice(int minPrice, int maxPrice) {
        Node current = head;
        while (current != null) {
            if (current.data.getPrice() >= minPrice && current.data.getPrice() <= maxPrice) {
                System.out.println(current.data);
            }
            current = current.next;
        }
    }

    public void sortByPrice() {
        Node current = head;
        while (current != null) {
            Node minNode = current;
            Node innerCurrent = current.next;
            while (innerCurrent != null) {
                if (innerCurrent.data.getPrice() < minNode.data.getPrice()) {
                    minNode = innerCurrent;
                }
                innerCurrent = innerCurrent.next;
            }
            if (current != minNode) {
                MobilePhone tmp = current.data;
                current.data = minNode.data;
                minNode.data = tmp;
            }
            current = current.next;
        }
    }
}

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("请输入手机个数：");
        int n = scanner.nextInt();
        LinkedList list = new LinkedList();
        for (int i = 0; i < n; i++) {
            System.out.print("请输入第" + (i+1) + "个手机型号和价格：");
            String type = scanner.next();
            int price = scanner.nextInt();
            MobilePhone phone = new MobilePhone(type, price);
            list.add(phone);
        }
        System.out.println("按价格从低到高排序后的手机列表：");
        list.sortByPrice();
        list.print();
        System.out.print("请输入要查找的手机型号：");
        String type = scanner.next();
        MobilePhone phone = list.findByType(type);
        if (phone != null) {
            System.out.println("找到了该型号的手机：" + phone);
        } else {
            System.out.println("没有找到该型号的手机。");
        }
        System.out.print("请输入要查找的价格区间（最低价格和最高价格，用空格隔开）：");
        int minPrice = scanner.nextInt();
        int maxPrice = scanner.nextInt();
        System.out.println("价格在" + minPrice + "元和" + maxPrice + "元之间的手机有：");
        list.findByPrice(minPrice, maxPrice);
    }
}

这个程序中，MobilePhone 表示手机类，LinkedList 表示链表类，Node 表示链表中的节点。在 main 函数中，首先从键盘输入 n 个手机对象，并添加到链表中。然后按照价格从低到高排序，并输出所有手机的信息。接下来，从键盘输入要查找的手机型号和价格区间，并使用链表中的方法进行查找。注意，为了方便起见，这里只实现了按价格从低到高排序，而没有实现按价格从高到低排序。