How to use BeanMapHandler with field to column mapping with key as ID in a nested SELECT query?

Question

I have a nested SQL query to fetch employee details using their ID.

Right now I am using BeanListHandler to fetch data as a List<Details> but want to store it as a Map<String, Details> where the ID I originally pass needs to be the key for easy retrieval instead of searching the List with streams every time.

I have tried to convert to Maps but I am not sure of how to map the ID as String nor how to get the original ID passed to the inner Query as a column in the final result.

MainTest.java:

String candidateId = "('1111', '2222', '3333', '4444')";

String detailsQuery =
    "select PARTNER, BIRTHDT, XSEXM, XSEXF from \"schema\".\"platform.view/table2\" where partner IN \r\n"
            + "(select SID from \"schema\".\"platform.view/table1\" where TYPE='BB' and CLASS='yy' and ID IN \r\n"
            + "(select SID from \"schema\".\"platform.view/table1\" where TYPE='AA' and CLASS='zz' and ID IN"
            + candidateId + "\r\n" + "))";

Map<String, Details> detailsView = queryRunner.query(conn, detailsQuery, new DetailsViewHandler());

Details.java:

public class Details {

    private String candidateId;
    private String birthDate;
    private String maleSex;
    private String femaleSex;

    // getter and setter
}

DetailsViewHandler.java:

public class DetailsViewHandler extends BeanMapHandler<String, Details> {

    public DetailsViewHandler() {
        super(Details.class, new BasicRowProcessor(new BeanProcessor(getColumnsToFieldsMap())));
    }

    public static Map<String, String> getColumnsToFieldsMap() {
        Map<String, String> columnsToFieldsMap = new HashMap<>();
        columnsToFieldsMap.put("PARTNER", "candidateId");
        columnsToFieldsMap.put("BIRTHDT", "birthDate");
        columnsToFieldsMap.put("XSEXM", "maleSex");
        columnsToFieldsMap.put("XSEXF", "femaleSex");
        return columnsToFieldsMap;
    }
}

Is there a way to get the ID (candidateId) in the result and what am I missing in terms of creating the key-value pairing ?

Answer 1

From the doc https://commons.apache.org/proper/commons-dbutils/apidocs/org/apache/commons/dbutils/handlers/BeanMapHandler.html of constructor which you are using

public BeanMapHandler(Class<V> type,
                      RowProcessor convert)

// Creates a new instance of BeanMapHandler. The value of the first column of each row will be a key in the Map.

Above should work.

You can also try overriding createKey like so

protected K createKey(ResultSet rs)
               throws SQLException {
return rs.getString("PARTNER"); // or getInt whatever suits

}