如何在jaxrs中显示服务器关闭或不可用警报

public class ServerUnavailableException extends WebApplicationException {
    public ServerUnavailableException() {
        super(Response.Status.SERVICE_UNAVAILABLE);
    }
}

@Provider
public class ServerUnavailableExceptionHandler implements ExceptionMapper<ServerUnavailableException> {
    @Override
    public Response toResponse(ServerUnavailableException exception) {
        // 构建自定义的错误响应
        ErrorMessage errorMessage = new ErrorMessage("服务器关闭或不可用", 503);
        return Response.status(Response.Status.SERVICE_UNAVAILABLE)
                .entity(errorMessage)
                .type(MediaType.APPLICATION_JSON)
                .build();
    }
}

@ApplicationPath("/api")
public class MyApplication extends Application {
    @Override
    public Set<Class<?>> getClasses() {
        Set<Class<?>> classes = new HashSet<>();
        classes.add(ServerUnavailableExceptionHandler.class);
        return classes;
    }
}

public class ErrorMessage {
    private String message;
    private int status;

    // 构造方法、getter和setter方法

    // ...
}