代码效率、调试、对象方法、数组

Question

我更多地练习对象、数组和方法。现在我正在编写一个简单的簿记程序来添加一本书，按标题、作者、价格、库存编号和流派搜索书籍。我有几个问题，一是修复这个程序（在方法fillBook（）中添加一本书），二是如何从对象类中删除一本书，三是如何使这个程序更高效

目前正在研究和阅读ioexception类。

这是我得到的错误java:66：错误：类手册中的构造函数手册不能应用于给定的类型
Book tempBook=新书（）
^
必需：字符串、字符串、double、int、字符串
找到：没有参数
原因：实际参数列表和形式参数列表长度不同
1个错误

工具已完成，退出代码为1模板对象类

public class Book
{
private String title;
private String author;
private double price;
private int inventoryNumber;
private String category;

private static int numberOfBooks = 0;

public Book(String bookTitle, String bookAuthor, double bookPrice, int bookInventoryNumber, String bookCategory)
{
    title = bookTitle;
    author = bookAuthor;
    price = bookPrice;
    inventoryNumber = bookInventoryNumber;
    category = bookCategory;
    numberOfBooks++;
}//end 5 args Book Constructor

public String getTitle()  {return title;}
public void setTitle(String t)  {title = t;}

public String getAuthor() {return author;}
public void setAuthor(String a)  {author = a;}

public double getPrice() {return price;}
public void setPrice(double p)  {price = p;}

public int getInventoryNumber() {return inventoryNumber;}
public void setInventoryNumber(int i)  {inventoryNumber = i;}

public String getCategory()  {return category;}
public void setCategory(String c)  {category = c;}

public static int getNumberOfBooks()  {return numberOfBooks;}

public String toString ()
{
    StringBuffer sb = new StringBuffer();
    sb.append("Title: " + title);
    sb.append("\nAuthor: " + author);
    sb.append("\nPrice: " + price);
    sb.append("\nInventoryNumber: " + inventoryNumber);
    sb.append("\nCategory: " + category + "\n\n");
    return (new String (sb));
}//end toString

public static String searchByTitle(Book[] newBook, String seachName)
{
    String message = "";
    for(int i=0; i<getNumberOfBooks(); i++)
    {
        if (seachName.equalsIgnoreCase(newBook[i].getTitle()))
        {
            message += newBook[i].toString();
        }//end if
    }//end for
    return message;
}//end searchByTitle

public static String searchByAuthor(Book[] newBook, String seachName)
{
    String message = "";
    for(int i=0; i<getNumberOfBooks(); i++)
    {
        if (seachName.equalsIgnoreCase(newBook[i].getAuthor()))
        {
            message += newBook[i].toString();
        }//end if
    }//end for
    return message;
}//end searchByAuthor

public static String searchByPrice(Book[] newBook, double seachPrice)
{
    String message = "";
    for(int i=0; i<getNumberOfBooks(); i++)
    {
        if (seachPrice == newBook[i].getPrice())
        {
            message += newBook[i].toString();
        }//end if
    }//end for
    return message;
}//end searchByPrice

public static String searchByInventory(Book[] newBook, int seachInventory)
    {
        String message = "";
        for(int i=0; i<getNumberOfBooks(); i++)
        {
            if (seachInventory == newBook[i].getInventoryNumber())
            {
                message += newBook[i].toString();
            }//end if
        }//end for
        return message;
}//end searchByInventory

public static String searchByCategory(Book[] newBook, String seachName)
    {
        String message = "";
        for(int i=0; i<getNumberOfBooks(); i++)
        {
            if (seachName.equalsIgnoreCase(newBook[i].getCategory()))
            {
                message += newBook[i].toString();
            }//end if
        }//end for
        return message;
}//end searchByAuthor

}//end class

运行程序类

import javax.swing.JOptionPane;

class FindBook
{
public static void main(String[] args)
{
    Book[] newBook = new Book[2000];
    newBook[0] = new Book("Game of Thrones", "George R. R. Martin", 39.95, 3, "fiction");
    newBook[1] = new Book("A Song of Ice and Fire", "George R. R. Martin", 34.50, 3, "fiction");
    newBook[2] = new Book("Java Programming For Dummies", "Donald Koosis", 59.29, 12, "non fiction");
    newBook[3] = new Book("Java™ Programming: From Problem Analysis to Program Design, 5th Edition", "Malik", 140.49, 4, "non fiction");
    newBook[4] = new Book("Life of Pi", "Yann Martel", 12.50, 3, "childrens");

    boolean continueOption = true;
    //****************menu bar********************/
    do {
        int menuOption = getMenu();
        switch (menuOption)
        {
            case 1: addBook(newBook); break;
            case 2: searchByTitle(newBook); break;
            case 3: searchByAuthor(newBook); break;
            case 4: searchByPrice(newBook); break;
            case 5: searchByInventory(newBook); break;
            case 6: searchByCategory(newBook); break;
            case 7: displayAllBookInfo(newBook); break;
            case 8: continueOption = false; break;
            default: JOptionPane.showMessageDialog(null, "Invalid choice"); break;
        }//end menu
    }while (continueOption);

    JOptionPane.showMessageDialog(null, "Thank You Come Again");

}//end main

public static int getMenu()
{
    String message;
    int choice;
    message = "\n1. Add a book in the book database: \n"
    + "2. Search book database by title: \n"
    + "3. Search books database by author: \n"
    + "4. Search books database by price: \n"
    + "5. Search books database by inventory: \n"
    + "6. Search books database by category: \n"
    + "7. Display all book information: \n"
    + "8. Exit the program\n\n"
    + "Please enter in a number from the menu to choose.";
    choice = Integer.parseInt(JOptionPane.showInputDialog(null,message));
    return choice;
} // end getMenu method

// option to add another book
public static void addBook(Book[] aBook)
{
    int select;
    do{
        aBook[Book.getNumberOfBooks()] = fillBook();
        select = JOptionPane.showConfirmDialog(null, "Add another book?");
    }while (select == JOptionPane.YES_OPTION && Book.getNumberOfBooks() < 2000);
}//end method add book

//filling in a book into book array
public static Book fillBook()
{
    Book tempBook = new Book();
    tempBook.setTitle(JOptionPane.showInputDialog(null, "Enter a title"));
    tempBook.setAuthor(JOptionPane.showInputDialog(null, "Enter an author"));
    tempBook.setPrice(Double.parseDouble(JOptionPane.showInputDialog(null, "Enter in a Price")));
    tempBook.setInventoryNumber(Integer.parseInt(JOptionPane.showInputDialog(null, "Enter in how many book(s) are in inventory")));
    tempBook.setCategory(JOptionPane.showInputDialog(null, "Enter in the category"));
    return tempBook;
}//end fillBook


public static void searchByTitle(Book[] aBook)
{
    String message = "";
    String searchTitle = "";
    searchTitle = JOptionPane.showInputDialog(null, "What title do you want to search for?");
    message = Book.searchByTitle(aBook, searchTitle);
    JOptionPane.showMessageDialog(null, message);
}//end method searchByTitle

public static void searchByAuthor(Book[] aBook)
{
    String message = "";
    String searchAuthor = "";
    searchAuthor = JOptionPane.showInputDialog(null, "What Author do you want to search for?");
    message = Book.searchByAuthor(aBook, searchAuthor);
    JOptionPane.showMessageDialog(null, message);
}//end method searchByAuthor

public static void searchByPrice(Book[] aBook)
{
    String message = "";
    double searchPrice = Double.parseDouble(JOptionPane.showInputDialog(null, "What Author do you want to search for?"));
    message = Book.searchByPrice(aBook, searchPrice);
    JOptionPane.showMessageDialog(null, message);
}//end method searchByPrice

public static void searchByInventory(Book[] aBook)
{
    String message = "";
    int seachInventory = Integer.parseInt(JOptionPane.showInputDialog(null, "What Author do you want to search for?"));
    message = Book.searchByInventory(aBook, seachInventory);
    JOptionPane.showMessageDialog(null, message);
}//end method searchByInventory

public static void searchByCategory(Book[] aBook)
{
    String message = "";
    String searchCategory = "";
    searchCategory = JOptionPane.showInputDialog(null, "What Author do you want to search for?");
    message = Book.searchByCategory(aBook, searchCategory);
    JOptionPane.showMessageDialog(null, message);
}//end method searchByCategory

public static void displayAllBookInfo(Book[] aBook)
{
    String message ="";
    for(int i=0; i<Book.getNumberOfBooks(); i++)
    {
        message += aBook[i].toString();
    }//end for loop for displayAllBookInfo
    JOptionPane.showMessageDialog(null, message);
}//end method displayAllBookInfo


}//end class

Answer 1

您需要为Book类添加默认构造函数。一旦您提供了参数化构造函数，java将不会自动创建默认conatructor，因此您需要提供它。

Book temBook=new Book（）；将在您的类中提供以下构造函数后开始工作。

Public Book(){
//implementation
}