好的，所以我使用bluej在java中做一个项目，我的任务是写一个图书馆系统，我有一个问题，当我创建一个新成员或在库类中预订，我可以在创建时将其添加到我的数组列表中吗？它可能非常简单，但我无法弄明白。
这里是我的代码，如果有人觉得他们想看看我道歉，如果它没有正确但这是我第一次发布在论坛上：
import java.util.*;
/**
* The library class represents an enrolment list for a library. It stores
* the library name, address and members of the library, as well as the libraries opening times.
*
* @author Kelvin Goodram
* @version 2014.11.01
*/
public class Library
{
//name of library to be written as a string ("" "")
private String libraryName;
//address of library to be written as a string ("" "")
private String address;
//opening times of library to be written as a string ("" "")
private String openingTimes;
private List<Member> members;
private List<Book> books;
//the member ID to be written as a whole integer number
private int capacity;
//the member ID to be written as a whole integer number
private int bookCapacity;
//the memebers fullname to be written as a string ("" "")
private String name;
//the member ID to be written as a whole integer number
private int id;
//members contact number to be written as a string ("" "")
private String tele;
//books author to be written as a string ("" "")
private String author;
//books title to be written as a string ("" "")
private String title;
//books reference number to be written as a whole integer number
private int refNum;
//books genre to be written as a string ("" "")
private String genre;
/**
* Create a Library with an option to input a maximum number of members & books. All other details
* are set to default values.
*/
public Library(int maxNumberOfMembers, int maxNumberOfBooks)
{
libraryName = "Bolton Central Library";
address = "110-119 Le Mans Cresent Bolton BL1 1SE";
openingTimes = "Open Monday - Friday (8am-7pm)";
members = new ArrayList<Member>();
books = new ArrayList<Book>();
capacity = maxNumberOfMembers;
bookCapacity = maxNumberOfBooks;
}
/**
* Add a member to this Library.
*/
public void addMember(String fullName, String telephoneNumber)
{
// if the member capacity has been reached
if(members.size() == capacity) {
// do this
System.out.println("The Library is not currently taking new members as we are full, please enroll at a different library.");
}
//otherwise do this:
else {
name = fullName;
tele = telephoneNumber;
id = 0;
}
}
/**
* Add a book to this Library.
*/
public void addBook(String bookAuthor, String bookTitle, int bookRef, String bookGenre)
{
// if the book capacity has been reached
if(books.size() == capacity) {
//do this
System.out.println("The Library currently does not have space for new books.");
}
//otherwise do this:
else {
author = bookAuthor;
title = bookTitle;
refNum = bookRef;
genre = bookGenre;
}
}
/**
* Return the number of members currently enrolled in this Library.
*/
public int numberOfMembers()
{
return members.size(); //returns an integer number of how many members are in the arrayList <Member>
}
/**
* Return the number of books currently registered in this Library.
*/
public int numberOfBooks()
{
return books.size(); //returns an integer number of how many books are in the arrayList <Book>
}
/**
* Set the Name for this Library.
*/
public void changeLibraryName(String LibName)
{
libraryName = LibName; //enter a string value to mutate the library name
}
/**
* alter the opening times for this Library. The parameter should define the opening hour
* and the closing time, such as "open Mon - Friday: 10am - 5pm".
*/
public void changeOpeningTimes(String timeAndDayString)
{
openingTimes = timeAndDayString; //enter a string value to mutate the library opening times
}
/**
* Alter the street address of the library.
*/
public void changeAdress(String streetAddress)
{
address = streetAddress; //enter a string value to mutate the library treet address
}
/**
* Print out a member list to the standard
* terminal.
*/
public void printMemberList()
{
System.out.println("***************************"); //header
System.out.println("LibraryName " + libraryName);
System.out.println("Address:" + address);
System.out.println("Opening Times:" + openingTimes);
System.out.println("-------------------------------"); //break
System.out.println("Member list:");
for(Member member : members) {
member.print();
}
System.out.println("Number of members: " + numberOfMembers());
System.out.println("***************************"); //footer
}
/**
* Print out a book list to the standard
* terminal.
*/
public void printBookList()
{
System.out.println("***************************"); //header
System.out.println("LibraryName " + libraryName);
System.out.println("Address:" + address);
System.out.println("Opening Times:" + openingTimes);
System.out.println("-------------------------------"); //break
System.out.println("Book list:");
for(Book book : books) {
book.print();
}
System.out.println("Number of books: " + numberOfBooks());
System.out.println("***************************"); //footer
}
}
我确实有另外两个类，这本书看起来像这样：
/**
* A class that maintains information on a book.
*
*
* @author (Insert your name here.)
* @version (Insert today's date here.)
*/
class Book
{
// The fields.
private String author;
private String title;
private String genre;
private int refNum;
/**
* Set the author, title fields and reference number when this object
* is constructed.
*/
public Book(String bookAuthor, String bookTitle, int bookRef, String bookGenre )
{
author = bookAuthor;
title = bookTitle;
refNum = bookRef;
genre = bookGenre;
}
/**
* Print the author's name, book title, ref number and genre to the o utput terminal.
*/
public void print()
{
System.out.println("Author = " +author);
System.out.println("Title = " +title);
System.out.println("Book Reference = " +refNum);
System.out.println("This book can be found in the " +genre + " section");
System.out.println("----------------------------------------------------");
}
}
答案 0 :(得分：0)
You should take a look in the Java List API
add(E e)
Appends the specified element to the end of this list (optional operation).
add(int index, E element)
Inserts the specified element at the specified position in this list (optional operation).
如果您不需要指定索引，可以执行以下操作：
books.add(newbook);
会员和书籍将是另外两个班级。您想要创建书籍和成员的对象，因此您正在做的事情可能不起作用，您应该为每个人创建一个类。 顺便说一句，当你创建一本书时，你应该这样做：
Book newbook = new Book(param1, param2....);
你应该有这样一个类：
public class Book
{
//variables_
private String name;^
//Constructor
public Book(String name, String...){
this.name = name;
this..... = ....;
}
//methods
public String getName(){
return name;
}
etc....
}
然后在您的库类中，您可以创建此类的新对象。