How to use and syntax Java custom annotations

Description

1. When using @interface to customize annotations, the java.lang.annotation.Annnotationion interface and the compiler automatically complete other details.

2. When defining annotations, other annotations or interfaces cannot be inherited. interface is used to declare annotations where various methods actually declare configuration parameters. The name of the method is the name of the parameter, and the type of the return value is the type of the parameter (the types of return values ​​are only basic types, Class, String, and enum). Parameter default values ​​can be declared through default.

Usage range

All basic data types (int, float, double, boolean, byte, char, long, short)

String type

Class type

enum type

Annotation type.

The above types of arrays.

Example

RequiresLogin.java
 
@Documented
@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
public @interface RequiresLogin {
 
}

What is Java

Java is an object-oriented programming language that can write desktop applications, Web applications, distributed systems and embedded system applications.

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