如果键是非标准对象，则JSF中的HashMap不会显示该值

Question

I have a HashMap which looks like this:

HashMap<QualifiedProduct,List<Date>

so my java code looks like this:

@Name("testController")
@AutoCreate
public class TestController {
public HashMap<QualifiedProduct, List<Date>> createAndReturnHashmap(){

    HashMap<QualifiedProduct, List<Date>> hm = new HashMap<QualifiedProduct, List<Date>>();

    QualifiedProduct q1= new QualifiedProduct();
    q1.setAbstractProductId(1);
    q1.setAbstractProductCode("1-1");
    q1.setAbstractProductName("one");
    q1.setAbstractProductTypeName("type1");
    q1.setCustomersCount(1);
    q1.setQualificationDueDate(new Date());
    q1.setQualificationsCount(1);

    QualifiedProduct q2= new QualifiedProduct();
    q2.setAbstractProductId(2);
    q2.setAbstractProductCode("2-2");
    q2.setAbstractProductName("two");
    q2.setAbstractProductTypeName("type2");
    q2.setCustomersCount(2);
    q2.setQualificationDueDate(new Date());
    q2.setQualificationsCount(2);

    QualifiedProduct q3= new QualifiedProduct();
    q3.setAbstractProductId(3);
    q3.setAbstractProductCode("3-3");
    q3.setAbstractProductName("three");
    q3.setAbstractProductTypeName("type3");
    q3.setCustomersCount(3);
    q3.setQualificationDueDate(new Date());
    q3.setQualificationsCount(3);



    List<Date> dt = new ArrayList<Date>();
    Date d1 = new Date();
    Date d2 = new Date();
    Date d3 = new Date();
    dt.add(d1);
    dt.add(d2);
    dt.add(d3);
    hm.put(q1, dt);
    hm.put(q2, dt);
    hm.put(q3, dt);

    return hm;

}

as i read in many other postings on stackoverflow like here ,or here the best way to show it in JSF 1.2 is using the good old jsp tag <c:forEach

So i used in my code:

xmlns:c="http://java.sun.com/jstl/core"
.....
<c:forEach var="hm" items="${testController.createAndReturnHashmap()}">
  ${hm.key} <br/>
  and value is:  ${hm.value} <br/><br/>
</c:forEach>

The JSF output is:

com.dw.model.QualifiedProduct@15d97b65[abstractProductId=2,abstractProductCode=2-2,abstractProductName=two,abstractProductTypeName=type2,qualificationsCount=2,customersCount=2,qualificationDueDate=Thu Jun 11 14:47:37 CEST 2015,id=,version=,created=,modified=] and value is:

com.dw.model.QualifiedProduct@2393366a[abstractProductId=1,abstractProductCode=1-1,abstractProductName=one,abstractProductTypeName=type1,qualificationsCount=1,customersCount=1,qualificationDueDate=Thu Jun 11 14:47:37 CEST 2015,id=,version=,created=,modified=] and value is:

com.dw.model.QualifiedProduct@79342f17[abstractProductId=3,abstractProductCode=3-3,abstractProductName=three,abstractProductTypeName=type3,qualificationsCount=3,customersCount=3,qualificationDueDate=Thu Jun 11 14:47:37 CEST 2015,id=,version=,created=,modified=] and value is:

So the value is always empty.

but if i use a HashMap like this HashMap<String,List<Date>> everything works:

public HashMap<String, List<Date>> createAndReturnHashmap(){

    HashMap<String, List<Date>> hm = new HashMap<String, List<Date>>();

    List<Date> dt = new ArrayList<Date>();
    Date d1 = new Date();
    Date d2 = new Date();
    Date d3 = new Date();
    dt.add(d1);
    dt.add(d2);
    dt.add(d3);
    hm.put("one", dt);
    hm.put("two", dt);
    hm.put("three",dt);

    return hm;

}

and the result is:

two and value is: [Thu Jun 11 14:54:22 CEST 2015, Thu Jun 11 14:54:22 CEST 2015, Thu Jun 11 14:54:22 CEST 2015]

one and value is: [Thu Jun 11 14:54:22 CEST 2015, Thu Jun 11 14:54:22 CEST 2015, Thu Jun 11 14:54:22 CEST 2015]

three and value is: [Thu Jun 11 14:54:22 CEST 2015, Thu Jun 11 14:54:22 CEST 2015, Thu Jun 11 14:54:22 CEST 2015]

Where is the differenct in using a non Standard object as a key???

Answer 1

Updating the answer as you changed the question.

If you want to use custom object as key in HashMap , you have to override hashCode() and equals() method in your custom object. here is the example of how to do that .

---

Previous answer for checking size of list in jsp ( original question.)

Try using ${fn:length(myItem.value)} to check list size. For this add <%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %> in your jsp

EL works on getters and setter. If you are doing list.size , it looks for a method list.getSize() on List object, which is not there. It has list.size() instead. So we have to use this jstl function to retrieve size of list.

Answer 2

as far as i recognized, the forEach is not working with a non java-standard object. the best is to make a wrapper class

public class QualificationProductWithListOfOrderingMailingDate {

    private HashMap<QualifiedProduct,List<Date>> qualificationProductWithListOfOrderingMailingDate;

    public HashMap<QualifiedProduct,List<Date>> getQualificationProductWithListOfOrderingMailingDate() {
        return qualificationProductWithListOfOrderingMailingDate;
    }

    public void setQualificationProductWithListOfOrderingMailingDate(
            HashMap<QualifiedProduct,List<Date>> qualificationProductWithListOfOrderingMailingDate) {
        this.qualificationProductWithListOfOrderingMailingDate = qualificationProductWithListOfOrderingMailingDate;
    } 

}

than it is no problem at all to loop over every product:

<ui:repeat var="x" value="#{testController.createAndReturnHashmap()}">
    #{x.qualifiedProduct.abstractProductId},#{x.qualifiedProduct.abstractProductCode}

    <ui:repeat var="dt" value="#{x.dates}">
            #{dt}
    </ui:repeat>

</ui:repeat>