fix typo (#3491)

Author: kezhenxu94

dubbo-common/src/main/java/org/apache/dubbo/common/Constants.java

@@ -247,7 +247,7 @@ public class Constants {
 
     public static final String PROTOCOL_KEY = "protocol";
 
-    public static final String DOBBO_PROTOCOL = DUBBO;
+    public static final String DUBBO_PROTOCOL = DUBBO;
 
     public static final String ZOOKEEPER_PROTOCOL = "zookeeper";
 

dubbo-config/dubbo-config-api/src/main/java/org/apache/dubbo/config/AbstractInterfaceConfig.java

@@ -350,12 +350,12 @@ protected URL loadMonitor(URL registryURL) {
                 if (getExtensionLoader(MonitorFactory.class).hasExtension("logstat")) {
                     map.put(Constants.PROTOCOL_KEY, "logstat");
                 } else {
-                    map.put(Constants.PROTOCOL_KEY, Constants.DOBBO_PROTOCOL);
+                    map.put(Constants.PROTOCOL_KEY, Constants.DUBBO_PROTOCOL);
                 }
             }
             return UrlUtils.parseURL(address, map);
         } else if (Constants.REGISTRY_PROTOCOL.equals(monitor.getProtocol()) && registryURL != null) {
-          return registryURL.setProtocol(Constants.DOBBO_PROTOCOL).addParameter(Constants.PROTOCOL_KEY, Constants.REGISTRY_PROTOCOL).addParameterAndEncoded(Constants.REFER_KEY, StringUtils.toQueryString(map));
+          return registryURL.setProtocol(Constants.DUBBO_PROTOCOL).addParameter(Constants.PROTOCOL_KEY, Constants.REGISTRY_PROTOCOL).addParameterAndEncoded(Constants.REFER_KEY, StringUtils.toQueryString(map));
         }
         return null;
     }

dubbo-config/dubbo-config-api/src/main/java/org/apache/dubbo/config/ProtocolConfig.java

@@ -317,7 +317,7 @@ public String getCodec() {
     }
 
     public void setCodec(String codec) {
-        if (Constants.DOBBO_PROTOCOL.equals(name)) {
+        if (Constants.DUBBO_PROTOCOL.equals(name)) {
             checkMultiExtension(Codec.class, Constants.CODEC_KEY, codec);
         }
         this.codec = codec;
@@ -328,7 +328,7 @@ public String getSerialization() {
     }
 
     public void setSerialization(String serialization) {
-        if (Constants.DOBBO_PROTOCOL.equals(name)) {
+        if (Constants.DUBBO_PROTOCOL.equals(name)) {
             checkMultiExtension(Serialization.class, Constants.SERIALIZATION_KEY, serialization);
         }
         this.serialization = serialization;
@@ -371,7 +371,7 @@ public String getServer() {
     }
 
     public void setServer(String server) {
-        if (Constants.DOBBO_PROTOCOL.equals(name)) {
+        if (Constants.DUBBO_PROTOCOL.equals(name)) {
             checkMultiExtension(Transporter.class, Constants.SERVER_KEY, server);
         }
         this.server = server;
@@ -382,7 +382,7 @@ public String getClient() {
     }
 
     public void setClient(String client) {
-        if (Constants.DOBBO_PROTOCOL.equals(name)) {
+        if (Constants.DUBBO_PROTOCOL.equals(name)) {
             checkMultiExtension(Transporter.class, Constants.CLIENT_KEY, client);
         }
         this.client = client;