Java 如何打印来自其他类的toString
我试图在对话框中打印书名和isbn。 我对java相当陌生,我的Java 如何打印来自其他类的toString,java,Java,我试图在对话框中打印书名和isbn。 我对java相当陌生,我的toString()无法工作,我需要帮助 public class Book { private String title; private String author; private String isbn; private Double price; private Publisher publisher; public Bo
toString()
无法工作,我需要帮助
public class Book
{
private String title;
private String author;
private String isbn;
private Double price;
private Publisher publisher;
public Book()
{
setTitle("");
setAuthor("");
setIsbn("");
setPrice(0.0);
setPublisher(new Publisher());
}
public Book(String t, String a, String i, double p, Publisher n)
{
setTitle(t);
setAuthor(a);
setIsbn(i);
setPrice(p);
setPublisher(n);
}
public void setTitle(String t)
{
title = t;
}
public String getTitle()
{
return title;
}
public void setAuthor(String a)
{
author = a;
}
public String getAuthor()
{
return author;
}
public void setIsbn(String i)
{
isbn = i;
}
public String getIsbn()
{
return isbn;
}
public void setPrice(double p)
{
price = p;
}
public double getPrice()
{
return price;
}
public void setPublisher(Publisher n)
{
publisher = n;
}
public Publisher getPublisher()
{
return publisher;
}
public double calculateTotal(int quantity)
{
return(price * quantity);
}
public String toString()
{
return( "Title" + title + "Author" + author + "Isbn" + isbn
+ "Price" + price + "Publisher" + publisher.toString());
}
}
import javax.swing. JOptionPane;
public class BookTest
{
public static void main(String args[])
{
String dataArray[][] = {{"Abraham Lincoln Vampire Hunter","Grahame-Smith","978-0446563079","13.99", "Haper", "NY"},
{"Frankenstein","Shelley","978-0486282114","7.99","Pearson", "TX"},
{"Dracula","Stoker","978-0486411095","5.99","Double Day", "CA"},
{"Curse of the Wolfman"," Hageman","B00381AKHG","10.59","Harper", "NY"},
{"The Mummy","Rice","978-0345369949","7.99","Nelson", "GA"}}; //book info
Book bookArray[] = new Book[dataArray.length];
int quantityArray[] = {12, 3, 7, 23, 5};
for (int i = 0; i < dataArray.length; i++)
{
bookArray[i] = new Book(dataArray[i][0], dataArray[i][1], dataArray[i][2],
Double.parseDouble(dataArray[i][3]), new Publisher(dataArray[i][4], dataArray[i][5]));
}
for (int i = 0; i < bookArray.length; i++)
{
bookArray[i].calculateTotal(quantityArray[i]);
}
JOptionPane.showMessageDialog(null, Book.toString());
}
}
公共课堂教材
{
私有字符串标题;
私有字符串作者;
专用字符串isbn;
私人双价;
私营出版商;
公共书籍()
{
片名(“”);
作者(“”);
setIsbn(“”);
设定价格(0.0);
setPublisher(newpublisher());
}
公共图书(字符串t、字符串a、字符串i、双p、出版商n)
{
片名(t);
作者(a);
setIsbn(i);
设定价格(p);
setPublisher(n);
}
公共void setTitle(字符串t)
{
title=t;
}
公共字符串getTitle()
{
返回标题;
}
public void setAuthor(字符串a)
{
作者=a;
}
公共字符串getAuthor()
{
返回作者;
}
公共无效集合ISBN(字符串i)
{
isbn=i;
}
公共字符串getIsbn()
{
返回isbn;
}
公共无效设定价格(双p)
{
价格=p;
}
公开双价
{
退货价格;
}
public void setPublisher(Publisher n)
{
publisher=n;
}
公共发布服务器getPublisher()
{
返回出版商;
}
公共双计算总计(整数数量)
{
退货(价格*数量);
}
公共字符串toString()
{
返回(“标题”+标题+“作者”+作者+“Isbn”+Isbn
+“Price”+Price+“Publisher”+Publisher.toString());
}
}
导入javax.swing。JOptionPane;
公开课图书考试
{
公共静态void main(字符串参数[])
{
字符串数据数组[][]={{“亚伯拉罕·林肯吸血鬼猎人”、“格雷厄姆·史密斯”、“978-0446563079”、“13.99”、“哈珀”、“纽约”},
{“弗兰肯斯坦”、“雪莱”、“978-0486282114”、“7.99”、“皮尔逊”、“德克萨斯州”},
{“德古拉”、“斯托克”、“978-0486411095”、“5.99”、“双日”、“CA”},
{“狼人的诅咒”、“哈格曼”、“B00381AKHG”、“10.59”、“哈珀”、“纽约”},
{“木乃伊”、“赖斯”、“978-0345369949”、“7.99”、“纳尔逊”、“GA”};//图书信息
Book bookArray[]=新书[dataArray.length];
int quantityArray[]={12,3,7,23,5};
for(int i=0;i
当您通过类的名称而不是引用该类实例的变量来限定该方法时,您正试图调用类书上名为toString的静态方法。Book类中没有定义这样的方法
相反,您应该调用book实例上的toString(),例如bookArray中的实例
例如,下面是在循环内部调用的toString:
for (int i = 0; i < bookArray.length; i++)
{
Book b = bookArray[i];
b.calculateTotal(quantityArray[i]);
//Using JOptionPane.showMessageDialog here only for an example, this probably isn't the OPs intent
JOptionPane.showMessageDialog(null, b.toString(););
}
for(int i=0;i
有关静态如何工作的参考,请参阅和
有关重写toString的更多信息,请参阅
JOptionPane.showMessageDialog(null, Book.toString());
您正试图静态调用toString
,这在一书中未定义
您需要从Book
实例中调用它。您的代码看起来很模糊
toString()的问题在下面的代码部分中
for (int i = 0; i < bookArray.length; i++)
{
bookArray[i].calculateTotal(quantityArray[i]);
}
JOptionPane.showMessageDialog(null, Book.toString());
for(int i=0;i
当调用Book.toString()时,实际上是从类Book调用方法。要打印书籍内容,您应该在for循环中插入代码,并使用书籍实例
for (int i = 0; i < bookArray.length; i++)
{
bookArray[i].calculateTotal(quantityArray[i]);
JOptionPane.showMessageDialog(null, bookArray[i].toString());
}
for(int i=0;i
PS:请使用IDE及其自动格式化实用程序
对于Eclipse,您可以使用Control+Shift+F对于Intellij IDEAControl+Alt+L您所说的无法让我的toString工作是什么意思?Clarify您正在调用Book
上的toString
,这是类名,但无论如何,您都试图在类型为Book
的数组对象上调用它,意思是bookArray[]
。您的toString()
仅适用于Book
的单个实例。解决方案是调用Arrays.toString(bookArray[])