fixed compiler error

driver/src/main/java/com/alibaba/otter/canal/parse/driver/mysql/socket/SocketChannelPool.java

@@ -6,7 +6,6 @@ import io.netty.buffer.PooledByteBufAllocator;
 import io.netty.channel.AdaptiveRecvByteBufAllocator;
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelFuture;
-import io.netty.channel.ChannelFutureListener;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInboundHandlerAdapter;
 import io.netty.channel.ChannelInitializer;
@@ -20,8 +19,10 @@ import java.io.IOException;
 import java.net.SocketAddress;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.CountDownLatch;
 
-import com.alibaba.otter.canal.common.utils.BooleanMutex;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * @author luoyaogui 实现channel的管理（监听连接、读数据、回收） 2016-12-28
@@ -29,9 +30,10 @@ import com.alibaba.otter.canal.common.utils.BooleanMutex;
 @SuppressWarnings({ "rawtypes", "deprecation" })
 public abstract class SocketChannelPool {
 
-    private static EventLoopGroup              group     = new NioEventLoopGroup();                        // 非阻塞IO线程组
-    private static Bootstrap                   boot      = new Bootstrap();                                // 主
+    private static EventLoopGroup              group     = new NioEventLoopGroup();                         // 非阻塞IO线程组
+    private static Bootstrap                   boot      = new Bootstrap();                                 // 主
     private static Map<Channel, SocketChannel> chManager = new ConcurrentHashMap<Channel, SocketChannel>();
+    private static final Logger                logger    = LoggerFactory.getLogger(SocketChannelPool.class);
 
     static {
         boot.group(group)
@@ -71,8 +73,8 @@ public abstract class SocketChannelPool {
 
     public static class BusinessHandler extends ChannelInboundHandlerAdapter {
 
-        private SocketChannel socket = null;
-        private final CountDownLatch latch = new CountDownLatch(1);
+        private SocketChannel        socket = null;
+        private final CountDownLatch latch  = new CountDownLatch(1);
 
         @Override
         public void channelInactive(ChannelHandlerContext ctx) throws Exception {
@@ -81,20 +83,20 @@ public abstract class SocketChannelPool {
         }
 
         @Override
-		public void channelActive(ChannelHandlerContext ctx) throws Exception {
-			socket = new SocketChannel();
-			socket.setChannel(ctx.channel());
-			chManager.put(ctx.channel(), socket);
-			latch.countDown();
-			super.channelActive(ctx);
-		}
+        public void channelActive(ChannelHandlerContext ctx) throws Exception {
+            socket = new SocketChannel();
+            socket.setChannel(ctx.channel());
+            chManager.put(ctx.channel(), socket);
+            latch.countDown();
+            super.channelActive(ctx);
+        }
 
         @Override
         public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
             if (socket != null) {
                 socket.writeCache((ByteBuf) msg);
             } else {
-                //TODO: need graceful error handler.
+                // TODO: need graceful error handler.
                 logger.error("no socket available.");
             }
             ReferenceCountUtil.release(msg);// 添加防止内存泄漏的