ibatis value should be Integer but I get Hashmap

Question

I have a problem on retrieving data from DB.

This is my method from DAO

@MapKey("key")
public Map<String, Integer> getMeasurementsPerNode() throws SQLException;

There is mapper

<select id="getMeasurementsPerNode" resultType="hashmap">
    SELECT 
        w.wd_ip AS `key`,
        COUNT(m.id) AS `value` 
    FROM t_workers w
    LEFT JOIN t_measurements m ON w.id = m.worker_id AND m.measurement_timestamp <![CDATA[>]]> DATE_SUB(NOW(), INTERVAL 1 HOUR)
    WHERE w.active = 1
    AND w.worker_type_id = 1
    GROUP BY w.wd_ip 
    ORDER BY `value` DESC
</select>

My problem is when I want to use obtained value from map as Integer I get ClassCastException (Hashmap to Integer). Can you please help me.

This is loop where I use it:

protected Map<String, Integer> nodeMeasurementsCount = nodeMapper.getMeasurementsPerNode();
for (Map.Entry<String, Integer> nodeThread : nodeMeasurementsCount.entrySet()) {
    NodeRestartCounter nrc = new NodeRestartCounter();
    nrc.setNode(nodeThread.getKey());
    nrc.setMeasurementCount(nodeThread.getValue());
    nodeRestartCounterList.add(nrc);
}

Answer 1

You cannot do such kind of mapping.

The key and value in a Hashmap is contained in an Map.Entry object and cannot be directly mapped via SqlMaps.

https://docs.oracle.com/javase/7/docs/api/java/util/Map.Entry.html

When you mention the result type as hashmap (java.util.HashMap), the result is always a list of HashMap with each each map containing the column names as keys and their corresponding values as column values for a particular row.