use custom connection validator instead of sending SELECT 1 query

apollo-common/src/main/java/com/ctrip/framework/apollo/common/utils/DataSourceValidator.java

+package com.ctrip.framework.apollo.common.utils;
+
+import org.apache.tomcat.jdbc.pool.Validator;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.sql.Connection;
+
+/**
+ * @author Jason Song(song_s@ctrip.com)
+ */
+public class DataSourceValidator implements Validator {
+  private static final Logger LOGGER = LoggerFactory.getLogger(DataSourceValidator.class);
+  private static final int DEFAULT_VALIDATE_TIMEOUT_IN_SECONDS = 5;
+
+  @Override
+  public boolean validate(Connection connection, int validateAction) {
+    boolean isValid = false;
+    try {
+      isValid = connection.isValid(DEFAULT_VALIDATE_TIMEOUT_IN_SECONDS);
+    } catch (Throwable ex) {
+      LOGGER.warn("Data source validation error", ex);
+    }
+
+    return isValid;
+  }
+}

apollo-common/src/main/resources/application.properties

@@ -3,7 +3,8 @@ spring.http.converters.preferred-json-mapper=gson
 # DataSource
 spring.datasource.testWhileIdle=true
 spring.datasource.testOnBorrow=true
-spring.datasource.validationQuery=SELECT 1
+spring.datasource.validatorClassName=com.ctrip.framework.apollo.common.utils.DataSourceValidator
+spring.datasource.validationInterval=5000
 spring.datasource.initSQL=set names utf8mb4
 
 # Naming strategy