improve dynamic config support for DruidDataSourceStatLogger

src/main/java/com/alibaba/druid/pool/DruidDataSource.java

@@ -429,6 +429,10 @@ public class DruidDataSource extends DruidAbstractDataSource implements DruidDat
             if (exceptionSorter != null) {
                 exceptionSorter.configFromProperties(properties);
             }
+            
+            if (statLogger != null) {
+                statLogger.configFromProperties(properties);
+            }
         }
 
         this.connectProperties = properties;

src/main/java/com/alibaba/druid/pool/DruidDataSourceStatLogger.java

@@ -15,7 +15,11 @@
  */
 package com.alibaba.druid.pool;
 
+import java.util.Properties;
+
 public interface DruidDataSourceStatLogger {
 
     void log(DruidDataSourceStatValue statValue);
+    
+    void configFromProperties(Properties properties);
 }

src/main/java/com/alibaba/druid/pool/DruidDataSourceStatLoggerAdapter.java

@@ -0,0 +1,18 @@
+package com.alibaba.druid.pool;
+
+import java.util.Properties;
+
+
+public abstract class DruidDataSourceStatLoggerAdapter implements DruidDataSourceStatLogger {
+
+    @Override
+    public void log(DruidDataSourceStatValue statValue) {
+        
+    }
+
+    @Override
+    public void configFromProperties(Properties properties) {
+        
+    }
+
+}

src/main/java/com/alibaba/druid/pool/DruidDataSourceStatLoggerImpl.java

@@ -20,15 +20,25 @@ import static com.alibaba.druid.util.JdbcSqlStatUtils.rtrim;
 import java.util.ArrayList;
 import java.util.LinkedHashMap;
 import java.util.Map;
+import java.util.Properties;
 
 import com.alibaba.druid.stat.JdbcSqlStatValue;
 import com.alibaba.druid.support.json.JSONUtils;
 import com.alibaba.druid.support.logging.Log;
 import com.alibaba.druid.support.logging.LogFactory;
 
-public class DruidDataSourceStatLoggerImpl implements DruidDataSourceStatLogger {
+public class DruidDataSourceStatLoggerImpl extends DruidDataSourceStatLoggerAdapter {
 
     private static Log LOG = LogFactory.getLog(DruidDataSourceStatLoggerImpl.class);
+    
+    public DruidDataSourceStatLoggerImpl() {
+        this.configFromProperties(System.getProperties());
+    }
+    
+    @Override
+    public void configFromProperties(Properties properties) {
+        
+    }
 
     @Override
     public void log(DruidDataSourceStatValue statValue) {