How to create immutable data objects using Records in Java 14

How to use Records in Java 14 to create immutable data objects

In recent years, the development of the Java language has been continuously advancing, providing developers with more efficient and convenient tools. Records introduced in Java 14 are an exciting feature that simplifies the creation and management of immutable data objects. This article will introduce how to use Records in Java 14 to create immutable data objects and give some sample code.

Before we start discussing Records, we must first understand what immutable data objects are. Simply put, immutable data objects are objects that cannot be modified once created. It has some important features such as thread safety, easy testing and good performance.

In past versions of Java, we usually used classes to create immutable data objects. This method requires us to manually write some repetitive code, such as defining private variables, implementing getters methods, overriding equals and hashCode methods, etc. These repetitive tasks are tedious and error-prone.

In Java 14, Records solves this problem for us. Records is a new class declaration form that automatically generates some common methods and code, thereby simplifying the creation of immutable data objects. The following is an example of using Records to create immutable data objects:

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

In the above example, we defined a Person class as an immutable data object. This class contains only two fields: name and age, and does not have any methods. We don't need to explicitly define constructors, getters, or equals and hashCode methods. All of this will be automatically generated by Records.

The following are some practical cases of using Records to create immutable data objects.

Case 1: Student Information

Suppose we need to create a data object of student information, including three fields: student number, name and age. We can use Records to define this object:

public record Student(String id, String name, int age) {}

// 创建一个学生对象
Student student = new Student("1001", "张三", 18);

// 获取学生信息
String id = student.id();
String name = student.name();
int age = student.age();

System.out.println("学生信息：学号-" + id + "，姓名-" + name + "，年龄-" + age);

The Student class created through Records has automatically generated constructors and getters methods, and we can directly use these methods to obtain student information.

Case 2: Product Information

Suppose we need to create a data object of product information, including three fields: product name, price and inventory. We can use Records to define this object:

public record Product(String name, double price, int stock) {}

// 创建一个商品对象
Product product = new Product("Java编程入门", 68.0, 100);

// 获取商品信息
String name = product.name();
double price = product.price();
int stock = product.stock();

System.out.println("商品信息：名称-" + name + "，价格-" + price + "，库存-" + stock);

Similarly, the Product class created through Records has automatically generated constructors and getters methods, and we can directly use these methods to obtain product information.

Summary:

Through the above examples, we can see that using Records in Java 14 to create immutable data objects is very simple and efficient. Using Records can avoid manually writing a lot of repetitive code and improve development efficiency. Records can also help us provide clearer and more readable code, reducing the chance of errors.

However, it should be noted that although Records can simplify the creation of immutable data objects, it is not suitable for all class declarations. Records can only be used for classes that describe immutable data and cannot contain any methods that change the state of the data. Additionally, Records cannot be used in inheritance hierarchies.

To sum up, Records is a very useful feature in Java 14, which can help developers create immutable data objects more conveniently. I hope this article will help you understand and use Records. I hope you can give full play to the advantages of Records in future projects and improve development efficiency and code quality.

The above is the detailed content of How to create immutable data objects using Records in Java 14. For more information, please follow other related articles on the PHP Chinese website!