What is the purpose of @Value in Spring?

In Spring, the purpose of the @Value annotation is to inject values into properties or method parameters. It can be used to inject simple values like strings, integers, as well as complex values like arrays or collections.

The @Value annotation can be used in three locations:

1. Annotations on properties are used to directly inject property values, for example:
2. private String message = “Hello World”;
3. This injects the string “Hello World” into the message property.
4. The annotation is used on the parameters of constructor or setter methods to inject values into method parameters, for example:
5. Using the `@Autowired` annotation, the constructor of MyClass is injected with a value of “Hello World” for the message parameter.
6. This injects the string “Hello World” into the constructor parameter message of MyClass.
7. Annotations are placed on methods to inject the return value of the method, for example:
8. @Value(“#{myBean.myMethod()}”)
   public String retrieveMessage() {
   return message;
   }
9. This injects the return value of the myMethod method of myBean into the return value of the getMessage method.

The @Value annotation makes it easy to inject values from configuration files or other Spring components into properties or method parameters, achieving the functionality of dependency injection.