问题
Java/Spring newbie here. I've a question about auto wiring through SpringBoot.
I have an interface , an implementation , a main class and a configuration class like so :
ServiceInterface.java
public interface ServiceInterface {
static String serviceName = "service";
public void displayMessage();
public String getServiceName();
}
ServiceImpl1.java
public class ServiceImpl1 implements ServiceInterface{
static String serviceName = "default service value ";
public String getServiceName() {
return serviceName;
}
@Override
public void displayMessage()
{
System.out.println("This is implementation 1");
}
}
The main class :
@SpringBootApplication
public class App implements CommandLineRunner{
@Autowired
private ServiceInterface serviceInterface;
public static void main(String args[])
{
SpringApplication.run(App.class, args);
}
@Override
public void run(String... args) {
serviceInterface.displayMessage();
System.out.println(serviceInterface.getServiceName());
System.out.println(serviceInterface.serviceName );
}
}
AppConfig.java
@Configuration
public class AppConfig {
@Bean
ServiceInterface serviceInterface()
{
return new ServiceImpl1();
}
}
When I run the code , I get this as the output
This is implementation 1
service 1
default service value
Why is the variable 'serviceName' inside ServiceImpl1 implementation not accessible through the object created by Spring through autowiring ?
回答1:
Never mind.. I just figured out that variables declared inside an interface are static and final.
来源：https://stackoverflow.com/questions/30111451/spring-boot-interfaces-and-implementations