如何将变量的名称及其在 Java 中的类型作为输出获取？

Question

I have the following class:

public class Example {

    private String name;
    private int year;

    public Example() {

        name = "Clifford the big red dog";
        year = 2020;
    }

    public void showData() {
        // ?????
    }
}

Imagine in the main class I create an object of the previous class ( Example ) and execute it's constructor. Then I want to execute showData() and I would like to see the following output (given this example):

String name Clifford the big red dog
int year 2020

The main would look like this:

public static void main () {

    Example example = new Example();

    example.showData();
}

Is there any way I can do this?

Answer 1

Do it as follows:

class Example {

    private String name;
    private int year;

    public Example() {

        name = "Clifford the big red dog";
        year = 2020;
    }

    public void showData() {
        System.out.println(name.getClass().getSimpleName() + " name " + name);
        System.out.println(((Object) year).getClass().getSimpleName() + " year " + year);
    }
}

public class Main {
    public static void main(String[] args) {
        Example example = new Example();
        example.showData();
    }
}

Output:

String name Clifford the big red dog
Integer year 2020

However, since showData is a method of class Example which already knows about its instance variables, you can simply do it as:

class Example {

    private String name;
    private int year;

    public Example() {

        name = "Clifford the big red dog";
        year = 2020;
    }

    public void showData() {
        System.out.println("String name " + name);
        System.out.println("int year " + year);
    }
}

public class Main {
    public static void main(String[] args) {
        Example example = new Example();
        example.showData();
    }
}

Output:

String name Clifford the big red dog
int year 2020