关于@Value注解取不到值的几种情况

@Value("${ftpIP}")
private String ftpIP;

@Value("${ftpIP}")
private static String ftpIP; 
@Value("${ftpUserName}")
private final String ftpUserName;

public class FTPManagerService { 
 @Value("${ftpIP}")
 private static String ftpIP; 
}

public class FTPManagerService { 
 @Value("${ftpIP}")
 private static String ftpIP; 
} 
public class Test{
    
    FTPManagerService  f = new FTPManagerService ();
 
    
    @Autowired
    FTPManagerService  f2;
}

@Value("${tag}")
private String tagValue;

@Component //遗漏
class TestValue{
    @Value("${tag}")
    private String tagValue;
}

@Component 
class TestValue{
    @Value("${tag}")
    private String tagValue;
} 
class Test{
    ...
    TestValue testValue = new TestValue()