Fix when qos is disable,log will print every time. (#3397)

* fix when qos is disable,log will print every time.

* change qos server boos thread number 1

Author: LiZhenNet

dubbo-plugin/dubbo-qos/src/main/java/org/apache/dubbo/qos/protocol/QosProtocolWrapper.java

@@ -80,20 +80,20 @@ public void destroy() {
 
     private void startQosServer(URL url) {
         try {
-            boolean qosEnable = url.getParameter(QOS_ENABLE,true);
+            if (!hasStarted.compareAndSet(false, true)) {
+                return;
+            }
+
+            boolean qosEnable = url.getParameter(QOS_ENABLE, true);
             if (!qosEnable) {
                 logger.info("qos won't be started because it is disabled. " +
                         "Please check dubbo.application.qos.enable is configured either in system property, " +
                         "dubbo.properties or XML/spring-boot configuration.");
                 return;
             }
 
-            if (!hasStarted.compareAndSet(false, true)) {
-                return;
-            }
-
             int port = url.getParameter(QOS_PORT, QosConstants.DEFAULT_PORT);
-            boolean acceptForeignIp = Boolean.parseBoolean(url.getParameter(ACCEPT_FOREIGN_IP,"false"));
+            boolean acceptForeignIp = Boolean.parseBoolean(url.getParameter(ACCEPT_FOREIGN_IP, "false"));
             Server server = Server.getInstance();
             server.setPort(port);
             server.setAcceptForeignIp(acceptForeignIp);

dubbo-plugin/dubbo-qos/src/main/java/org/apache/dubbo/qos/server/Server.java

@@ -82,7 +82,7 @@ public void start() throws Throwable {
         if (!started.compareAndSet(false, true)) {
             return;
         }
-        boss = new NioEventLoopGroup(0, new DefaultThreadFactory("qos-boss", true));
+        boss = new NioEventLoopGroup(1, new DefaultThreadFactory("qos-boss", true));
         worker = new NioEventLoopGroup(0, new DefaultThreadFactory("qos-worker", true));
         ServerBootstrap serverBootstrap = new ServerBootstrap();
         serverBootstrap.group(boss, worker);