@Value Annotation Issues: Java Spring Solutions

There are a few possible reasons why the @Value annotation may not be able to read the value:

1. Configuration error in the property file: Make sure that the properties values to be read are correctly set in the property file, and that the property names match the expression in the @Value annotation.
2. If the Spring container does not scan the property file, then the @Value annotation will not be able to retrieve the values. Make sure to correctly configure the scan path for the property file in the Spring configuration file.
3. Classpath issue: If the property file is not in the classpath, the @Value annotation will not be able to retrieve the value. Make sure the property file is in the classpath, or use the classpath prefix to specify the location of the property file.
4. Type conversion issue: Sometimes the value read by the @Value annotation is not of the same type as the target type, causing injection failure. You can try using SpEL expressions for type conversion, or specify a default value with the @Value annotation properties.

If the above methods fail to solve the problem, consider using the @PropertySource annotation to load property files, or retrieve property values through the Environment object. If the issue persists, it may be necessary to check the Spring configuration files and project structure to ensure all configurations are correct.