How to use Records class in Java 14 instead of traditional DTO objects

How to use the Records class in Java 14 to replace the traditional DTO object

In traditional Java development, in order to transfer data between different levels, we usually use DTO (Data Transfer Object) object. A DTO object is a simple Java class used to encapsulate data and pass it between different components. However, creating and maintaining a large number of DTO classes can become tedious and redundant. Java 14 introduced the Records class, which provides a more concise and intuitive way to define data encapsulation classes.

The Records class can help us quickly create immutable data classes. It automatically generates constructors, getter methods, equals, hashCode, toString and other methods for us. Using the Records class can greatly reduce our workload in writing code while improving the readability and maintainability of the code.

The following is an example of using the Records class:

public record Person(String name, int age) {}

public class Main {
    public static void main(String[] args) {
        Person person = new Person("Alice", 25);
        System.out.println(person.name());
        System.out.println(person.age());
        System.out.println(person);
    }
}

In the above example, we define a Person class, which is declared using the keyword record. We also define two attributes: name and age. The Records class will automatically generate a constructor with parameters name and age, and the corresponding getter method.

In the main method, we use the new keyword to create a Person object, and obtain the attribute values ​​of the object by calling the name() and age() methods. Finally, by calling the toString() method, we can print the Person object directly.

In addition to the automatically generated methods, the Records class also provides us with some special functions. For example, the Records class automatically generates a final modifier for each property, making it an immutable field. This means that we cannot modify the property values ​​of the object after it is created, thus ensuring the object's immutability.

Another useful feature is that the Records class automatically implements the equals and hashCode methods for us. This means that we can use the == operator to compare two Records objects without having to manually write the equals method.

At the same time, the Records class also provides a very convenient copy method for creating a new object with the same properties as the original object but different values. Using the copy method, we can easily modify the property values ​​of an object without manually writing copy logic.

public record Person(String name, int age) {}

public class Main {
    public static void main(String[] args) {
        Person person = new Person("Alice", 25);
        Person modifiedPerson = person.withAge(30);
        System.out.println(modifiedPerson);
    }
}

In the above example, we use the withAge method to create a new Person object, in which the age attribute is modified to 30. We only need to modify the properties we care about, and do not need to pay attention to the values ​​​​of other properties.

The Records class can also be used with other features, such as pattern matching. Pattern matching is another important feature in Java 14 that helps us handle different states of objects more easily.

public record Person(String name, int age) {}

public class Main {
    public static void main(String[] args) {
        Person person = new Person("Alice", 25);

        if (person instanceof Person p) {
            System.out.println(p.name());
            System.out.println(p.age());
        }
    }
}

In the above example, we use pattern matching to bind the properties of the Person object to the variable p and output it in the if statement. This allows us to use the Records class more intuitively to handle different states of objects.

In summary, the Records class in Java 14 provides us with a more concise and intuitive way to define data encapsulation classes. By automatically generating constructors, getter methods, equals and other methods, we can greatly reduce the workload of writing code. At the same time, some special functions of the Records class and combination with other functions enable us to process data objects more efficiently. This makes the Records class a good choice to replace traditional DTO objects in Java development.

The above is the detailed content of How to use Records class in Java 14 instead of traditional DTO objects. For more information, please follow other related articles on the PHP Chinese website!