Often when displaying a list of dtos, you have to display a lookup value from a code file or another table.

There are a three ways to do this:
1. Stuff the lookup value into another value on the dto your using - 2 queries
2. Custom dto or custom sql which joins the lookup table - 1 query but takes a long time to develop

3. One query for your dtos, one for your types/lookup values and then put in a form map and display the lookup value from the form map - 2 querys, but the jsp is not super intuitive

I think 3 is pretty cool you dont have to do any special custom dto work as long as you know the jsp its pretty.

I'm using a bean called fuelmaster which has a field on it called trtype, and there is a table called fueltype which has fuel type descriptions in it for the trtype.


Action.java

        if (fuelForm.getFueltypeMap() == null
                || fuelForm.getFueltypeMap().size() == 0) {

           //store lookup values in a map with trtype/idx as the key
            FueltypeDao fueltypeDao = DaoFactory.getFueltypeDao();
            Fueltype[] fueltypeArray = fueltypeDao.findWhereCompEquals(fuelForm
                    .getCompanyId());
            HashMap map = new HashMap();
            for (Fueltype fueltype : fueltypeArray) {
                map.put(fueltype.getIdx(),  fueltype);
            }
            fuelForm.setFueltypeMap(map);
       }
...
//store your list of dtos in the form or in the request

            fuelmasterList = getFuelManager().getFuelmasters(params);
            log.info("fuelmasterList=" + fuelmasterList.size());

            fuelForm.setResults(fuelmasterList);


JSP

        <display:table
        name="${fuelForm.results}"
        requestURI="${requestUri}"
          pagesize="${pagesize}"
        id="fuelmaster"
        class="displaytag"
        cellpadding="0px" cellspacing="0px"
        export="true"
        defaultorder="ascending"
        partialList="false"
        style="vertical-align:top;"
        >

             .....

            <display:column title="Description" style="text-align:left" sortable="true" headerClass="leftalign">         
                <c:set var="fueltypeDto" value="${fuelForm.fueltypeMap[fuelmaster.trtype]}" />
                <c:out value="${fueltypeDto.descr}" />
            </display:column>