我应该在java中创建一个库程序，允许您创建顾客并查看最多3本书。我是java的初学者，所以我很抱歉我的代码遍布整个地方，可能没有意义。
下面是我尝试过的库类（我还有一个单独的Patron，Book和Book Interface类） 我主要担心的是：
我有2个ArrayLists，一个用于输入用户列表，另一个用于输入书籍列表。但是，我如何能够将某些已检出的书籍分配给某个用户＆amp;确保他们借的不超过3个？
我在main方法中放了很多代码，但最后我遇到了很多静态和非静态的问题
我如何才能创建状态＆＃39;每本书？例如，如果＆＃34;伟大的期望＆＃34;签出，如何分配＆＃34;借来＆＃34;对它，并确保没有其他人可以借用它？
该计划到目前为止运行但缺乏深度，因为我失去了如何在特定指定赞助人下查看/阅读书籍。
再次对我的代码中的所有不一致感到抱歉，我非常感谢您的帮助！
import java.awt.List;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Scanner;
import java.util.Collections;
public class Library
{
static ArrayList <Patron> UserList = new ArrayList<Patron>();
static ArrayList <String> BookList = new ArrayList <String> ();
public static String status;
public static String borrower;
public static String borrowDate;
public static String returnDate;
public String status1 = "Available";
public String status2 = "Borrowed";
public static void main(String[] args)
{
Scanner input = new Scanner(System.in);
int choice = 0;
System.out.println("********************Welcome to the Public Library!********************");
System.out.println(" Please Select From The Following Options: ");
System.out.println("**********************************************************************");
while(choice != 9)
{
System.out.println("1: Add new patron");
System.out.println("2: Add new book");
System.out.println("3: Edit patron");
System.out.println("4: Edit book");
System.out.println("5: Display all patrons");
System.out.println("6: Display all books");
System.out.println("7: Check out book");
System.out.println("8: Check in book");
System.out.println("9: Search book");
System.out.println("10: Search Patron");
System.out.println("9: Exit");
choice = input.nextInt();
switch(choice)
{
case 1: //Add new patron
System.out.print("Enter patron first name: ");
String firstName = input.next(); //read name from input
System.out.print("Enter patron last name: ");
String lastName = input.next();
UserList.add(new Patron(firstName, lastName)); //add name to list
System.out.println("-----You have successfully added a new patron!-----");
break;
case 2: //Add new book
System.out.print("Enter book title: ");
String title1 = input.next();
Scanner input1 = new Scanner(System.in);
System.out.print("Enter book author: ");
String author1 = input.next();
Book book1 = new Book(title1);
BookList.add(title1);
FullBookList.add(fullBook);
System.out.println("-----You have successfully added a new book!-----");
status = "available";
borrowDate = "none";
returnDate = "none";
borrower = "none";
break;
case 3: //Edit patron name
System.out.println("Enter original patron name: ");
String originalName = input.next();
System.out.println("Enter edited patron name: ");
String editedName = input.next();
//Collections.replaceAll(UserList, originalName, editedName);
if(UserList.contains(originalName))
{
}
case 4: //edit book
case 5: //display all patrons
System.out.println(UserList);
break;
case 6: //display all books
System.out.println(BookList);
break;
case 7: //check out a book
Patron.CheckOutBook();
break;
case 8: //check in a book
Patron.CheckInBook();
break;
}
}
}
}
import java.util.ArrayList;
import java.util.Scanner;
public class Patron
{
Scanner input = new Scanner(System.in);
private String first;
private String last;
int bookCount = 0; //amount books user has in pocket
int books = 0;
//constructor to "add new patron" by entering their name.
public Patron(String f, String l)
{
first = f;
last = l;
}
public String toString()
{
return first + " " + last;
}
public String getName()
{
return first + " " + last;
}
public static void CheckOutBook()
{
System.out.println("Enter book title to be check out: ");
Scanner input = new Scanner(System.in);
String bookCheckOut = input.next();
if(Library.BookList.contains(bookCheckOut))
{
Library.BookList.remove(bookCheckOut);
System.out.println("-----" + bookCheckOut + " has been checked out!-----");
System.out.println ("-------" + bookCheckOut + " is due in 7 days!-------");
}
else
System.out.println(bookCheckOut + " is not in the library. Please enter "
+ "a different book to be checked out");
}
public static void CheckInBook()
{
System.out.println("Enter book title to be checked in: ");
Scanner input = new Scanner(System.in);
String bookCheckIn = input.next();
if(Library.BookList.contains(bookCheckIn))
{
Library.BookList.add(bookCheckIn);
System.out.println("-----" + bookCheckIn + " has been checked in!-----");
}
else
System.out.println(bookCheckIn + " is not in the library. Please enter "
+ "a different book to be checked out");
}
public boolean canBorrow()
{
if(bookCount <= 3)
{
return true;
}
else
{
return false;
}
}
}
答案 0 :(得分：1)
注意：这可能会涉及对主循环进行一些重构。
好吧，所以我看到它的方式，我们在这里有三个课程：一些Patrons，可以检查书籍，一些书籍，其状态如“可用”和“签出”，以及图书馆，其中包含书籍。所以，我们需要3个班级：
我将从Book开始并使用伪代码来解释您要实现的概念。
class Book
{
//private fields
private final String title;
private final String author;
private Status available = true;
//note--i would prefer using an Enum called status for this,
//but a boolean true/false value works adequately
//Constructor
public Book(string title, string author) {}
//accessors for title, author, available
//setter for available--used for Library only--there are better ways to ensure
//Patrons can't set the status of the book, but for now this is the simplest way
}
如您所见，Books具有不需要更改的不可变字段，以及一个跟踪其状态的字段。更好的实现可能会使Library跟踪书状态，因为这会使逻辑意义更强，代码更好，但这是一个简单的实现。
接下来，图书馆，需要大量的书籍：
class Library
{
private final ArrayList<Book> books;
//Constructor
public Library ()
{
books = loadBooks();
}
//some methods
private ArrayList<Book> loadBooks () {}
//however you want to create all your books (file input, whatever)
public bool isBookAvailable (Book b)
{
if b isn't in library: return false
else return (b in books).isAvailable()
}
public Book checkoutBook (Book b)
{ get book (checking availability, possibly returning a null Book), set status to unavailable, return it }
public Book checkinBook (Book b)
{ check that this the book belongs to library, set status to available }
}
正如我先前所说，这并不完美。我可以花一些时间继续讨论如何改进设计，但为了简单起见，不会。
现在，赞助人。一个问题是，Patrons只有一个图书馆可以访问吗？或者他们访问多个图书馆？我假设他们不止一次访问，因为有时候图书馆没有你想要的所有书籍。
class Patron
{
private final String name;
private final Book[] books = new Book[3];//you can see I'm limiting them to 3 books
private int index = 0;
//Constructor
public Patron (String name) {}
//methods
public void checkoutBook (Book b, Library l)
{//could be tricky
check books status in l (l.isBookAvailable(b))
if available:
if space (index < 2) Book newBook = l.checkoutBook(b); books[index++] = newBook;
else: no space
else: not available
}
public void checkinBook (int bookIndex, Library l)
{
if bookIndex < 3:
if books[index] != null:
l.checkinBook (books[index]);
books[index--] = null;
else: no book
else: not valid index
}
}
当然，其他实用程序，如显示书籍（库，赞助人）和toString方法可能会有用。但现在主要方法的责任是创建一些顾客，图书馆，并让顾客有机会通过菜单结账和签入书籍。你完成了繁重的工作;你现在可以处理输入和输出。
有问题吗？
答案 1 :(得分：1)
JAVA中的入门级“学生图书馆计划”，它与学生和书籍互动。该图书馆程序可以执行以下功能：
1-将图书添加到图书馆。
2-更新图书数量。
3-搜索书籍及其序列号。
使用作者姓名的4-Search图书。
5-显示所有书籍及其相关信息。
6-注册学生。
7-显示所有注册学生。
8位学生可以从图书馆签出图书（如果已注册）。
：-学生最多只能签出3本书
：-如果图书在图书馆可用，您只能借书
9位学生可以将图书签到图书馆。
10-您还可以查看学生已签出的书（仅在签入时）
Note: At the time it can store only 50 books for simlicity in program
我用我在Java中拥有的最高技能和知识创建了该程序。因为我是初学者，所以我无法做更多事
请给有关计划的评论
也请告诉我要在程序中进行的改进
请告诉我执行此计划的更好方法
package library;
import java.util.Scanner;
public class book {
public int sNo;
public String bookName;
public String authorName;
public int bookQty;
public int bookQtyCopy;
Scanner input = new Scanner(System.in);
public book(){
System.out.println("Enter Serial No of Book:");
this.sNo = input.nextInt();
input.nextLine();
System.out.println("Enter Book Name:");
this.bookName = input.nextLine();
System.out.println("Enter Author Name:");
this.authorName = input.nextLine();
System.out.println("Enter Quantity of Books:");
this.bookQty = input.nextInt();
bookQtyCopy = this.bookQty;
}
}
package library;
import java.util.Scanner;
public class books {
book theBooks[] = new book[50]; // Array that stores 'book' Objects.
public static int count; // Counter for No of book objects Added in Array.
Scanner input = new Scanner(System.in);
public int compareBookObjects(book b1, book b2){
if (b1.bookName.equalsIgnoreCase(b2.bookName)){
System.out.println("Book of this Name Already Exists.");
return 0;
}
if (b1.sNo==b2.sNo){
System.out.println("Book of this Serial No Already Exists.");
return 0;
}
return 1;
}
public void addBook(book b){
for (int i=0; i<count; i++){
if (this.compareBookObjects(b, this.theBooks[i]) == 0)
return;
}
if (count<50){
theBooks[count] = b;
count++;
}
else{
System.out.println("No Space to Add More Books.");
}
}
public void searchBySno(){
System.out.println("\t\t\t\tSEARCH BY SERIAL NUMBER\n");
int sNo;
System.out.println("Enter Serial No of Book:");
sNo = input.nextInt();
int flag = 0;
System.out.println("S.No\t\tName\t\tAuthor\t\tAvailable Qty\t\tTotal Qty");
for (int i=0; i<count; i++){
if (sNo == theBooks[i].sNo){
System.out.println(theBooks[i].sNo + "\t\t" + theBooks[i].bookName + "\t\t" + theBooks[i].authorName + "\t\t" +
theBooks[i].bookQtyCopy + "\t\t" + theBooks[i].bookQty);
flag++;
return;
}
}
if (flag == 0)
System.out.println("No Book for Serial No " + sNo + " Found.");
}
public void searchByAuthorName(){
System.out.println("\t\t\t\tSEARCH BY AUTHOR'S NAME");
input.nextLine();
System.out.println("Enter Author Name:");
String authorName = input.nextLine();
int flag = 0;
System.out.println("S.No\t\tName\t\tAuthor\t\tAvailable Qty\t\tTotal Qty");
for (int i=0; i<count; i++){
if (authorName.equalsIgnoreCase(theBooks[i].authorName)){
System.out.println(theBooks[i].sNo + "\t\t" + theBooks[i].bookName + "\t\t" + theBooks[i].authorName + "\t\t" +
theBooks[i].bookQtyCopy + "\t\t" + theBooks[i].bookQty);
flag++;
}
}
if (flag == 0)
System.out.println("No Books of " + authorName + " Found.");
}
public void showAllBooks(){
System.out.println("\t\t\t\tSHOWING ALL BOOKS\n");
System.out.println("S.No\t\tName\t\tAuthor\t\tAvailable Qty\t\tTotal Qty");
for (int i=0; i<count; i++){
System.out.println(theBooks[i].sNo + "\t\t" + theBooks[i].bookName + "\t\t" + theBooks[i].authorName + "\t\t" +
theBooks[i].bookQtyCopy + "\t\t" + theBooks[i].bookQty);
}
}
public void upgradeBookQty(){
System.out.println("\t\t\t\tUPGRADE QUANTITY OF A BOOK\n");
System.out.println("Enter Serial No of Book");
int sNo = input.nextInt();
for (int i=0; i<count; i++){
if (sNo == theBooks[i].sNo){
System.out.println("Enter No of Books to be Added:");
int addingQty = input.nextInt();
theBooks[i].bookQty += addingQty;
theBooks[i].bookQtyCopy += addingQty;
return;
}
}
}
public void dispMenu(){
System.out.println("----------------------------------------------------------------------------------------------------------");
System.out.println("Enter 0 to Exit Application.");
System.out.println("Enter 1 to Add new Book.");
System.out.println("Enter 2 to Upgrade Quantity of a Book.");
System.out.println("Enter 3 to Search a Book.");
System.out.println("Enter 4 to Show All Books.");
System.out.println("Enter 5 to Register Student.");
System.out.println("Enter 6 to Show All Registered Students.");
System.out.println("Enter 7 to Check Out Book. ");
System.out.println("Enter 8 to Check In Book");
System.out.println("-------------------------------------------------------------
---------------------------------------------");
}
public int isAvailable(int sNo){
//returns the index number if available
for (int i=0; i<count; i++){
if (sNo == theBooks[i].sNo){
if(theBooks[i].bookQtyCopy > 0){
System.out.println("Book is Available.");
return i;
}
System.out.println("Book is Unavailable");
return -1;
}
}
System.out.println("No Book of Serial Number " + " Available in Library.");
return -1;
}
public book checkOutBook(){
System.out.println("Enter Serial No of Book to be Checked Out.");
int sNo = input.nextInt();
int bookIndex =isAvailable(sNo);
if (bookIndex!=-1){
//int bookIndex = isAvailable(sNo);
theBooks[bookIndex].bookQtyCopy--;
return theBooks[bookIndex];
}
return null;
}
public void checkInBook(book b){
for (int i=0; i<count; i++){
if (b.equals(theBooks[i]) ){
theBooks[i].bookQtyCopy++;
return;
}
}
}
}
package library;
import java.util.Scanner;
public class student {
String studentName;
String regNum;
book borrowedBooks[] = new book[3];
public int booksCount = 0;
Scanner input = new Scanner(System.in);
public student(){
System.out.println("Enter Student Name:");
this.studentName = input.nextLine();
System.out.println("Enter Reg Number:");
this.regNum = input.nextLine();
}
}
package library;
import java.util.Scanner;
public class students {
Scanner input = new Scanner(System.in);
student theStudents[] = new student[50];
//books book;
public static int count = 0;
public void addStudent(student s){
for (int i=0; i<count; i++){
if(s.regNum.equalsIgnoreCase(theStudents[i].regNum)){
System.out.println("Student of Reg Num " + s.regNum + " is Already Registered.");
return;
}
}
if (count<=50){
theStudents[count] = s;
count++;
}
}
public void showAllStudents(){
System.out.println("Student Name\t\tReg Number");
for (int i=0; i<count; i++){
System.out.println(theStudents[i].studentName + "\t\t" + theStudents[i].regNum);
}
}
public int isStudent(){
//return index number of student if available
//System.out.println("Enter Student Name:");
//String studentName = input.nextLine();
System.out.println("Enter Reg Number:");
String regNum = input.nextLine();
for (int i=0; i<count; i++){
if (theStudents[i].regNum.equalsIgnoreCase(regNum)){
return i;
}
}
System.out.println("Student is not Registered.");
System.out.println("Get Registered First.");
return -1;
}
public void checkOutBook(books book){
int studentIndex =this.isStudent();
if (studentIndex!=-1){
System.out.println("checking out");
book.showAllBooks();//jjjjjjjjjjjj
book b = book.checkOutBook();
System.out.println("checking out");
if (b!= null){
if (theStudents[studentIndex].booksCount<=3){
System.out.println("adding book");
theStudents[studentIndex].borrowedBooks[theStudents[studentIndex].booksCount] = b;
theStudents[studentIndex].booksCount++;
return;
}
else {
System.out.println("Student Can not Borrow more than 3 Books.");
return;
}
}
System.out.println("Book is not Available.");
}
}
public void checkInBook(books book){
int studentIndex = this.isStudent();
if (studentIndex != -1){
System.out.println("S.No\t\t\tBook Name\t\t\tAuthor Name");
student s = theStudents[studentIndex];
for (int i=0; i<s.booksCount; i++){
System.out.println(s.borrowedBooks[i].sNo+ "\t\t\t" + s.borrowedBooks[i].bookName + "\t\t\t"+
s.borrowedBooks[i].authorName);
}
System.out.println("Enter Serial Number of Book to be Checked In:");
int sNo = input.nextInt();
for (int i=0; i<s.booksCount; i++){
if (sNo == s.borrowedBooks[i].sNo){
book.checkInBook(s.borrowedBooks[i]);
s.borrowedBooks[i]=null;
return;
}
}
System.out.println("Book of Serial No "+sNo+"not Found");
}
}
}
package library;
import java.util.Scanner;
public class Library {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.println("********************Welcome to the Student Library!********************");
System.out.println(" Please Select From The Following Options: ");
System.out.println("**********************************************************************");
books ob = new books();
students obStudent = new students();
int choice;
int searchChoice;
do{
ob.dispMenu();
choice = input.nextInt();
switch(choice){
case 1:
book b = new book();
ob.addBook(b);
break;
case 2:
ob.upgradeBookQty();
break;
case 3:
System.out.println("Enter 1 to Search with Serial No.");
System.out.println("Enter 2 to Search with Author Name(Full Name).");
searchChoice = input.nextInt();
switch(searchChoice){
case 1:
ob.searchBySno();
break;
case 2:
ob.searchByAuthorName();
}
break;
case 4:
ob.showAllBooks();
break;
case 5:
student s = new student();
obStudent.addStudent(s);
break;
case 6:
obStudent.showAllStudents();
break;
case 7:
obStudent.checkOutBook(ob);
break;
case 8:
obStudent.checkInBook(ob);
break;
default:
System.out.println("CHOICE SHOULD BE BETWEEN 0 TO 8.");
}
}
while (choice!=0);
}
}