com.alibaba.dubbo.governance.web.governance.module.screen.Providers#getServiceAppMap 
at line 133 ， should be providers.size > 0 or just delete this comparison cause the next for will skip if proviers.size == 0
import org.springframework.beans.factory.annotation.Autowired;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
/**
 * <p>Providers.</p>
 * URI: <br>
 * GET /providers, show all providers<br>
 * GET /providers/add, show web form for add a static provider<br>
 * POST /provider/create, create a static provider, save form<br>
 * GET /providers/$id, show provider details<br>
 * GET /providers/$id/edit, web form for edit provider<br>
 * POST /providers/$id, update provider, save form<br>
 * GET /providers/$id/delete, delete a provider<br>
 * GET /providers/$id/tostatic, transfer to static<br>
 * GET /providers/$id/todynamic, transfer to dynamic<br>
 * GET /providers/$id/enable, enable a provider<br>
 * GET /providers/$id/disable, disable a provider<br>
 * GET /providers/$id/reconnect, reconnect<br>
 * GET /providers/$id/recover, recover<br>
 * <br>
 * GET /services/$service/providers, show all provider of a specific service<br>
 * GET /services/$service/providers/add, show web form for add a static provider<br>
 * POST /services/$service/providers, save a static provider<br>