fix: 数组字符串为空值异常修复

@@ -20,24 +20,29 @@ import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Optional;
 
 public class ListStringTypeHandler extends BaseTypeHandler {
 
     @Override
     public Object getNullableResult(ResultSet rs, String columnName)
             throws SQLException {
-        return Arrays.asList(rs.getString(columnName).split(","));
+
+        String value = rs.getString(columnName);
+        return value ==null?null:Arrays.asList(value.split(","));
     }
 
     @Override
     public Object getNullableResult(ResultSet resultSet, int i) throws SQLException {
-        return Arrays.asList(resultSet.getString(i).split(","));
+        String value = resultSet.getString(i);
+        return value ==null?null:Arrays.asList(value.split(","));
     }
 
     @Override
     public Object getNullableResult(CallableStatement cs, int columnIndex)
             throws SQLException {
-        return Arrays.asList(cs.getString(columnIndex).split(","));
+        String value = cs.getString(columnIndex);
+        return value ==null?null:Arrays.asList(value.split(","));
     }
 
     @Override