What is the method for creating custom annotations in J…

In Java, the method for creating custom annotations is as follows:

1. Definition

public @interface MyAnnotation {
    // 注解元素
}

1. Annotations can be applied to elements such as primitive data types, Strings, Classes, enum types, annotation types, or arrays of them.

public @interface MyAnnotation {
    String value();  // 定义一个字符串类型的注解元素
    int count() default 1;  // 定义一个整数类型的注解元素，并设置默认值为1
}

1. When using annotations, you can specify corresponding values for the annotation elements.

@MyAnnotation(value = "Hello", count = 3)
public class MyClass {
    // 类的内容
}

1. Retrieve annotation information through reflection where annotations are needed.

MyAnnotation annotation = MyClass.class.getAnnotation(MyAnnotation.class);
String value = annotation.value();  // 获取注解元素的值
int count = annotation.count();

1. In places where annotations are needed, the use of default values for elements can simplify the use of annotations.

@MyAnnotation("Hello")
public class MyClass {
    // 类的内容
}