Java Records is a feature introduced in Java 16 to simplify the definition of immutable data classes. It automatically generates common methods such as constructors, getter methods, toString(), equals() and hashCode() through a line of code to reduce redundant code and improve development efficiency. Its advantages include simplicity, immutability, thread safety and ease of debugging; it is suitable for packaging when returning multiple values ??in DTO, JSON serialization, configuration classes and functional programming; but it is not suitable for scenarios where object state needs to be frequently modified or other classes need to be inherited; in addition, record can implement interfaces and support the addition of static factory methods to enhance readability, such as using Person.of("Tom", 25) to create objects; overall, record is an ideal choice to focus on storing immutable data.
Records in Java is a new feature introduced by Java 16, which is mainly used to simplify the definition of immutable data classes. If you have written classes like DTO (data transfer object) or POJO (normal Java object), you should have a deep understanding: these classes usually only contain fields, constructors, getter methods, equals/hashCode and toString methods. Record is to solve the problem of too much "boilerboard code".
What is Java Records?
Simply put, Record is a special class that focuses on storing immutable data and automatically provides many commonly used methods to implement it. You just need to declare the field name and type, and most other things will be done automatically by the compiler.
for example:
record Person(String name, int age) {} This Person record contains two fields: name and age , and automatically generates methods such as constructor, getter method, toString() , equals() and hashCode() .
Benefits of using Records
The biggest benefit of using Records is to reduce redundant code , allowing developers to focus more on business logic than boilerplate (boilerplate) code.
- Concise and clear : a complete data class can be defined in just one line of code.
- Immutability : All fields are final by default to ensure that the data is not modified.
- Thread safety : Due to immutability, thread safety is naturally supported.
- Easy to debug : The automatically generated
toString()method makes log output clearer.
For example, if we do not use record, we have to manually write the following content to achieve the same function:
public class Person {
private final String name;
private final int age;
public Person(String name, int age) {
this.name = name;
this.age = age;
}
public String name() { return name; }
public int age() { return age; }
// equals(), hashCode(), toString()
}If you use record, you can do it in one line.
How to use Records correctly?
Although record is convenient, it is not available anywhere. Here are some suggestions for use:
- Suitable for immutable data models : record is not for you if you need to modify object state frequently.
- Don't abuse inheritance : record cannot inherit other classes, it can only implement interfaces.
- You can add static methods or helper methods : record allows you to add static factory methods or other helper methods.
For example:
record Person(String name, int age) {
public static Person of(String name, int age) {
return new Person(name, age);
}
} This way you can create objects through Person.of("Tom", 25) to increase readability.
Which scenes are suitable for Records?
- Data Transfer Object (DTO)
- JSON serialization/deserialization (such as with Jackson or Gson)
- Small categories that store configuration information
- Encapsulation class when returning multiple values ??in functional programming
Frameworks like Spring Boot have also begun to support directly using record to return response data at the controller layer, which is very convenient.
In general, Java Records is a very practical language feature that can help you save a lot of time in repetitive encoding. As long as your class is mainly used to save data and does not want to be modified, record is a good choice.
Basically that's it.
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