私有实例变量/类定义

书，作为标题，作者和出版年份。包含获取和设置私有实例变量的方法以及toString方法来显示对象。另外创建一个方法moreRecent，它将两本书作为输入参数，并返回最近发布的一本书。为更多最近创建3个JUnit测试。

但是，我不知道如何访问其他私有实例变量author和yearofPub。我只能为每个类做一个构造函数吗？那么如何获得其他2个变量？这是我的代码到目前为止：谢谢！

class Book { 
private String title; 
private String author; 
private String yearofPub; 

Book(String input) { 
    title = input; 
} 


String moreRecent(int Book1, int Book2) { 
    String moreRecent; 
    if(Book1 > Book2) { 
     moreRecent = "Book 1"; 
    } 
    if (Book2 > Book1) { 
     moreRecent = "Book 2"; 
    } 
    else 
     moreRecent = "Both"; 
    return moreRecent; 

} 

} 

public class Chpt2930BookTitleAuthorYear { 

/** 
* @param args the command line arguments 
*/ 
public static void main(String[] args) { 
    Scanner scan = new Scanner(System.in); 
    System.out.println("Enter title of Book: "); 
    String nextLine = scan.next(); 
    Book titleofBook = new Book(nextLine); 

} 
}

编辑--------------------------

好感谢所有的答复！我进一步改进了我的代码，但仍无法获得正确的结果。我特别在更近的方法上遇到困难。我如何设置这些书的年份？这里是我的代码：

class Book { 

private String title; 
private String author; 
private String yearofPub; 

Book(String input) { 
    title = input.toString(); 
} 

public String getTitle() { 
    return title; 
} 

public void setTitle(String title) { 
    this.title = title; 
} 

public String getAuthor() { 
    return author; 
} 

public void setAuthor(String author) { 
    this.author = author; 
} 

public String getYearofPub() { 
    return yearofPub; 
} 

public void setYearofPub(String yearofPub) { 
    this.yearofPub = yearofPub; 
} 

public String toString() { 
    System.out.println("Book{" + "Title=" + title + " Author=" + author + " Year of 
     Publication=" + yearofPub + "}"); 
    return " "; 
} 
//confused on this part :(
String moreRecent(Book Book1, Book Book2) { 
    if (Book1.getYearofPub>Book.getYearofPub) { //Is this correct? I'm not sure :/ 

    } 
} 
} 

public class Chpt2930BookTitleAuthorYear { 

/** 
* @param args the command line arguments 
*/ 
public static void main(String[] args) { 
    Scanner scan = new Scanner(System.in); 
    System.out.println("Enter title of Book: "); 
    String nextLineTitle = scan.nextLine(); 
    Book titleofBook = new Book(nextLineTitle); 


    System.out.println("Enter author of the Book: "); 
    String nextLineAuthor = scan.nextLine(); 
    titleofBook.setAuthor(nextLineAuthor); 


    System.out.println("Enter the date of publication of the Book: "); 
    String nextLineDate = scan.nextLine(); 
    titleofBook.setYearofPub(nextLineDate); 

    titleofBook.toString(); 

} 
}

谢谢！

EDIT 2 -----------------

Nvm'd我发现这个问题:) 感谢所有帮助，虽然

来源

2013-12-19 Freedom

'包括如下的方法来获取和设置私有实例variables'做到这一点。然而，你不会在'MoreRecent（）'里面需要它们。另外为什么'moreRecent'具有'int'参数而不是'Book'参数？ –

这样做：

class Book { 

    private String title; 
    private String author; 
    private String yearofPub; 

    Book(String input) { 
     title = input; 
    } 

    public String getTitle() { 
     return title; 
    } 

    public void setTitle(String title) { 
     this.title = title; 
    } 

    public String getAuthor() { 
     return author; 
    } 

    public void setAuthor(String author) { 
     this.author = author; 
    } 

    public String getYearofPub() { 
     return yearofPub; 
    } 

    public void setYearofPub(String yearofPub) { 
     this.yearofPub = yearofPub; 
    } 



}

而在你的主要方法，您可以：

Book titleofBook = new Book(nextLine); 
titleofBook.setAuthor(...)

来源

2013-12-19 15:33:05 sanket

提供了这样称为访问变量。例如：

public String getAuthor() { 
    return this.author; 
} 

public void setAuthor(String author) { 
    this.author = author; 
}

同样适用于yeaofPub字段。

来源

2013-12-19 15:30:23

私有实例变量/类定义

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