Java: how to parse a string in this situation?

Question

So I have created a simple class in Java like this:

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

    public Book (String author, String title) {
        this.author = author;
        this.title = title;
    }
}

public void checkInfo

Is there a way to parse a string (property) in order to get Book properties like this, instead of doing bookA.title ?

Book bookA = new Book("George Orwell","Animal Farm")

String property = "title";
System.out.print(bookA.property);

Thanks in adance!

You could do something like `bookA.get(property);` (after you add a `get(String)` method in `Book`). I would prefer a `getTitle()` and `getAuthor()` (in which case you can access your fields with [JavaBean properties](https://docs.oracle.com/javase/tutorial/javabeans/writing/properties.html)). — Elliott Frisch, May 15 '16 at 02:02
you need to implement `getter` and `setters` for Class `Book`. It will be more Convenient and better approach which introduced by java. — Vikrant Kashyap, May 15 '16 at 02:05
I'm guessing that you don't actually intend to have ``static`` in your class definition. (Thinking you'd want multiple instances of ``Book``) — chsbellboy, May 15 '16 at 02:08
Thanks so much for the comments, the reason why i didnt implement getter methods is because, it the real case im working with, there will be a lot more properties, intead of just author and title. So maybe getter is the only way to accomplish this? — DanielleC, May 15 '16 at 02:11

Alexandre Lavoie · Accepted Answer · 2016-05-15T04:14:54.280

If you really want to access many properties as String, I suggest you using a Map<String, String> like this :

public class Book
{
    private Map<String, String> properties = new HashMap();

    public void setProperty(String name, String value)
    {
        properties.set(name,string);
    }

    public String getProperty(String name)
    {
        return properties.get(name);
    }
}

Now you can use like this :

Book book = new Book();

book.setProperty("title","Animal Farm");
book.setProperty("author","George Orwell");

System.out.println("Book: " + book.getProperty("title") + " by " + book.getProperty("author"))

score 1 · Answer 2 · edited May 23 '17 at 11:44

1

You've created your Book as an object.
So, treat it like an object and add getters and setters.

In this case, that would be a method, getTitle() and a separate method getAuthor().
For more information on getters and setters, see the responses to this previous StackOverflow post

edited May 23 '17 at 11:44

Community

1
1

answered May 15 '16 at 02:06

chsbellboy

490
2
15

score 1 · Answer 3 · answered May 15 '16 at 02:11

1

You can use reflection:

 Field f = bookA.getClass().getDeclaredField("title");
 f.setAccessible(true);
 String title = (String) f.get(bookA);
 System.out.println(title);

answered May 15 '16 at 02:11

IT_Nike

91
6

I think he is searching for a much easier solution than that xd – UDKOX May 15 '16 at 02:14
@UDKOX yeah it seems so)) – IT_Nike May 15 '16 at 02:19

score 1 · Answer 4 · answered May 15 '16 at 02:13

First of all, your code won't work because title is private. Second, I have no idea why you set Book class as static. Last, this (Java) is object oriented programming, so treat it like an object.

When you create a class you also add Getters & Setters to access the information inside. The code would look like this:

Class:

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

    public Book (String author, String title) {
        this.author = author;
        this.title = title;
    }
}

public String getTitle(){
    return this.title;
}

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

Accessing the data:

Book bookA = new Book("George Orwell","Animal Farm")

System.out.print("Book: " + bookA.getTitle() + " by " + bookA.getAuthor());

This would return :

Book: Animal Farm by George Orwell

score 0 · Answer 5 · edited May 15 '16 at 02:17

0

If you see these few lines from your code:

private String author;  // both are private variables
private String title;

Here author and title both are private String . So you can't access these properties outside of the class.

So, you'll need to add public getters and setters that can be used to access the properties.

edited May 15 '16 at 02:17

chsbellboy

490
2
15

answered May 15 '16 at 02:14

Vikrant Kashyap

6,398
3
32
52

score 0 · Answer 6 · answered May 15 '16 at 02:21

you should change you Object class.. add getter and setter method.. here is example :

public class Book{ 
  String myauthor;
  String mytitle;
public Book (String author, String title){
  myauthor=author;
  mytitle=title;
}
public void setAuthor(String Autor){
myauthor=author;
}
public String getAuthor(){
return myauthor;
}
}

and create setter and getter for 'title' too.. if you want to get the title / author, just simply call

Book.getAuthor();

score 0 · Answer 7 · answered May 15 '16 at 03:53

If you don't want to have getter/setter method for your class ;you can define access modifier as protected with static keyword.For example is: under com.test package-There are two class.One is Book class and other is BookInSamePackage class.In Book class;if you define attribute title as protected static String title then in BookInSamePackage class ;You can access like that :'Book.title'.If you want to use this title attribute in class of another package;then this class need to extend Book class and can access like this way:Book.title in child class of another package.

Java: how to parse a string in this situation?

7 Answers7