如何使用getter和setter获取用户输入

Question

I have created a getter and setter class as book and from that i am accessing setbookName,setbookPrice,setAuthorName similar get methods too but i am not able to take inputs from user please check my code

Scanner sc=new Scanner(System.in);
try
{
    System.out.println("Enter book name:");
    String bookName=sc.nextLine();
    System.out.println("Enter book price:");
    String bookPrice=sc.nextLine();
    System.out.println("Enter author name:");
    String authorName=sc.nextLine();
}
catch(Exception e)
{
    System.out.println("I/O Exception");
}
book b=new book();
b.setBookName(bookName);          //here i am facing error
b.setBookPrice(bookPrice);
b.setAuthorName(authorName);
    System.out.println("Book Details");
    System.out.println("Book Name"+b.getBookName());
    System.out.println("Book Name"+b.getBookPrice());
    System.out.println("Book Name"+b.getAuthorName());
}

// book class

    class book 
   {

     private String bookName;
    private String authorName;
    private String bookPrice;

    public String getBookName() {
        return bookName;
    }

    public void setBookName(String bookName) {
        this.bookName = bookName;
    }

    public String getAuthorName() {
        return authorName;
    }

    public void setAuthorName(String authorName) {
        this.authorName = authorName;
    }

    public String getBookPrice() {
        return bookPrice;
    }

    public void setBookPrice(String bookPrice) {
        this.bookPrice = bookPrice;
    }

Answer 1

Following is your main code - please see my comment that I've added to it...

For future reference, it would be helpful if you included the error messages you are getting. I'm assuming that the code is representative of what you are doing:

Scanner sc=new Scanner(System.in);
try
{
    System.out.println("Enter book name:");
    String bookName=sc.nextLine();
    System.out.println("Enter book price:");
    String bookPrice=sc.nextLine();
    System.out.println("Enter author name:");
    String authorName=sc.nextLine();
}
/********************
 * The variables bookName, bookPrice, authorName cease to exist after the above
 * curly brace.
 * If you want to access them beyond this point, you must declare them before
 * the try { statement.
 * Alternatively, move the declaration of your Book prior to the try statement
 * and set the properties of the book in the above try block
 * e.g. use b.setBookName(sc.nextLine())
 * instead of reading it into the String bookName variable.
 *************************************************/
catch(Exception e)
{
    System.out.println("I/O Exception");
}
book b=new book();
b.setBookName(bookName);          //here i am facing error
b.setBookPrice(bookPrice);
b.setAuthorName(authorName);
    System.out.println("Book Details");
    System.out.println("Book Name"+b.getBookName());
    System.out.println("Book Name"+b.getBookPrice());
    System.out.println("Book Name"+b.getAuthorName());
}

Following is one possible example of how to rewrite it:

Scanner sc=new Scanner(System.in);
book b=new book();
try
{
    System.out.println("Enter book name:");
    b.setBookName(sc.nextLine());
    System.out.println("Enter book price:");
    b.setBookPrice(sc.nextLine());
    System.out.println("Enter author name:");
    b.setAuthorName(sc.nextLine());
}
catch(Exception e)
{
    System.out.println("I/O Exception");
}

    System.out.println("Book Details");
    System.out.println("Book Name"+b.getBookName());
    System.out.println("Book Name"+b.getBookPrice());
    System.out.println("Book Name"+b.getAuthorName());
}

Answer 2

Book Class

public class Book {
private String BookName;
private String AuthorName;
private double BookPrice;
public String getBookName() {
    return this.BookName;
}
public void setBookName(String bookName) {
    this.BookName = bookName;
}
public String getAuthorName() {
    return AuthorName;
}
public void setAuthorName(String authorName) {
    this.AuthorName = authorName;
}
public double getBookPrice() {
    return this.BookPrice;
}
public void setBookPrice(String bookPrice) {
    try {
        this.BookPrice =Double.valueOf(bookPrice);
    } catch (Exception e) {
        e.printStackTrace();
    }   
}}  

Main class

public class App {
public static void main(String[] args) {
    Scanner sc=new Scanner(System.in);
    String bookName=null;//i think your error in hear
    String bookPrice=null;
    String authorName=null;
    try
    {
        System.out.println("Enter book name:");
        bookName=sc.nextLine();
        System.out.println("Enter book price:");
        bookPrice=sc.nextLine();
        System.out.println("Enter author name:");
        authorName=sc.nextLine();
    }
    catch(Exception e)
    {
        System.out.println("I/O Exception");
    }       
    Book b=new Book();
    b.setBookName(bookName);       
    b.setBookPrice(bookPrice);
    b.setAuthorName(authorName);
    System.out.println("Book Details");
    System.out.println("Book Name"+b.getBookName());
    System.out.println("Book Name"+b.getBookPrice());
    System.out.println("Book Name"+b.getAuthorName());      
    sc.close();
}}

this work for me