set utf8mb4 to support emoji

client-adapter/rdb/src/main/java/com/alibaba/otter/canal/client/adapter/rdb/RdbAdapter.java

@@ -2,10 +2,7 @@ package com.alibaba.otter.canal.client.adapter.rdb;
 
 import java.sql.Connection;
 import java.sql.SQLException;
-import java.util.LinkedHashMap;
-import java.util.List;
-import java.util.Map;
-import java.util.Properties;
+import java.util.*;
 import java.util.concurrent.ConcurrentHashMap;
 
 import javax.sql.DataSource;
@@ -123,6 +120,9 @@ public class RdbAdapter implements OuterAdapter {
         dataSource.setTimeBetweenEvictionRunsMillis(60000);
         dataSource.setMinEvictableIdleTimeMillis(300000);
         dataSource.setUseUnfairLock(true);
+        List<String> array = new ArrayList<>();
+        array.add("set names utf8mb4;");
+        dataSource.setConnectionInitSqls(array);
 
         try {
             dataSource.init();