spring cloud:Edgware.RELEASE版本中zuul回退方法的变化

public interface ZuulFallbackProvider {

	/**
	 * The route this fallback will be used for.
	 * @return The route the fallback will be used for.
	 */
	public String getRoute();

	/**
	 * Provides a fallback response.
	 * @return The fallback response.
	 */
	public ClientHttpResponse fallbackResponse();
}

public interface FallbackProvider extends ZuulFallbackProvider {

	/**
	 * Provides a fallback response based on the cause of the failed execution.
	 *
	 * @param cause cause of the main method failure
	 * @return the fallback response
	 */
	ClientHttpResponse fallbackResponse(Throwable cause);
}

if (cause != null && cause.getCause() != null) {
        String reason = cause.getCause().getMessage();
        //输出详细的回退原因
        ...
}