Minor fix (#214)

Fix string comparison
Fix possible index out of bound
diff --git a/dubbo-admin-backend/src/main/java/org/apache/dubbo/admin/config/ConfigCenter.java b/dubbo-admin-backend/src/main/java/org/apache/dubbo/admin/config/ConfigCenter.java
index 31af96f..0aa0442 100644
--- a/dubbo-admin-backend/src/main/java/org/apache/dubbo/admin/config/ConfigCenter.java
+++ b/dubbo-admin-backend/src/main/java/org/apache/dubbo/admin/config/ConfigCenter.java
@@ -103,7 +103,7 @@
     Registry getRegistry() {
         Registry registry = null;
         if (registryUrl == null) {
-            if (StringUtils.isNotEmpty(registryAddress)) {
+            if (StringUtils.isBlank(registryAddress)) {
                 throw new ConfigurationException("Either configcenter or registry address is needed");
             }
             registryUrl = formUrl(registryAddress, group);
@@ -129,11 +129,7 @@
     }
 
     private URL formUrl(String config, String group) {
-        String protocol = config.split("://")[0];
-        String address = config.split("://")[1];
-        String port = address.split(":")[1];
-        String host = address.split(":")[0];
-        URL url = new URL(protocol, host, Integer.parseInt(port));
+        URL url = URL.valueOf(config);
         if (StringUtils.isNotEmpty(group)) {
             url.addParameter(org.apache.dubbo.common.Constants.GROUP_KEY, group);
         }
diff --git a/dubbo-admin-backend/src/main/java/org/apache/dubbo/admin/service/impl/RouteServiceImpl.java b/dubbo-admin-backend/src/main/java/org/apache/dubbo/admin/service/impl/RouteServiceImpl.java
index f888113..b7e7def 100644
--- a/dubbo-admin-backend/src/main/java/org/apache/dubbo/admin/service/impl/RouteServiceImpl.java
+++ b/dubbo-admin-backend/src/main/java/org/apache/dubbo/admin/service/impl/RouteServiceImpl.java
@@ -339,14 +339,14 @@
                 String[] array = condition.split("=>", 2);
                 String consumer = array[0].trim();
                 String provider = array[1].trim();
-                if (consumer != "") {
+                if (consumer.length() != 0) {
                     if (when.length() != 0) {
                         when.append(" & ").append(consumer);
                     } else {
                         when.append(consumer);
                     }
                 }
-                if (provider != "") {
+                if (provider.length() != 0) {
                     if (then.length() != 0) {
                         then.append(" & ").append(provider);
                     } else {