java - 从书类简单获取作者姓名

Question

所以，我是面向对象编程的新手。我正在做下一个练习:

1. 给定一个定义为具有以下属性的类 Book:

   Author author;
   String title;
   int noOfPages;
   boolean fiction;
   

   为每个属性编写标准的 get/set 方法 header 。

2. [编码] 根据习题1中要求的属性和get/set方法实际编码编译Book类

   <

这是我的代码:

public class Author {

    //private variable
    private String name;
    private String gender;  
    //constructor
    public Author (String name, String gender){
        this.name = name;
        this.gender = gender;   
    }
    //getters
    public String getName(){
        return name;  
    }
    public String getGender(){
        return gender;
    }
public class Book {

    //private variables
    private Author author;
    private String title;
    private int noOfPages;
    private boolean fiction;

    //constructor
    public Book(String title, int noOfPages, boolean fiction){
        this.author=new Author ("Jacquie Barker","Female");
        this.title = title;
        this.noOfPages=noOfPages;
        this.fiction = fiction;    
    }

    //getters
    public Author getAuthorsName(){
        return this.author;
    }
    public String getTitle(){
        return title;
    }

    public int getNoOfPages(){
        return noOfPages;
    }

    public boolean getFiction(){
        return fiction;
    }

    //setters
    public void setAuthor(Author newAuthor){
        author=newAuthor;
    }
    public void setTitle (String title){
        this.title=title;
    }
    public void setNoOfPages(int noOfpages){
        this.noOfPages=noOfpages;
    }
    public void setfiction(boolean fiction){
        this.fiction=false;
    }

    public String toString(){
        return "Title: " + this.title + "\n"+"Author: " + this.author + "\n" +
               "No. of pages: " + this.noOfPages + "\n" + "Fiction: " + this.fiction;
    }
}

这是主要的摘录:

Title: Beginning in Java Objects

Author: book.Author@15db9742

No. of pages: 300

Fiction: true

如您所见，该程序不会打印作者姓名。

感谢所有帮助!

Answer 1

这里有两个选择。首先，您可以简单地重构 Book.toString() 方法中的代码来打印作者的真实姓名:

public String toString(){
    return "Title: " + this.title + "\n"+"Author: " + this.author.getName() + "\n" +
           "No. of pages: " + this.noOfPages + "\n" + "Fiction: " + 
}

其次，您可以覆盖 Author 类中的 toString() 方法以返回作者姓名。然后，您可以保留 Book.toString() 方法，因为当您尝试打印 Author< 时，Java 将调用此 toString() 方法 对象:

public class Author {
    // print the author's name when an Author object appears in a print statement
    public String toString() {
       return this.name;
    }
}

然后像你一样:

public class Book {
    public String toString(){
        return "Title: " + this.title + "\n"+"Author: " + this.author + "\n" +
           "No. of pages: " + this.noOfPages + "\n" + "Fiction: " + this.fiction;
    }
}