How to populate dropdown box in Spring MVC

Question

I have been trying to find out how to populate a dropdown box in Spring MVC. There are a few threads out there on this subject but none of them that I have found have helped

Answer 1

Not sure what Controller method is called to show your view with documentNumberList, but you need to add that collection to the model passed to this view:

model.addAttribute("documentNumberList", documentService.retrieveAllDocumentNumbers());

Though from your exception stack trace you also missed an @Autowired on documentService field.

Answer 2

I have solved this kind of problem today by myself. This is very simple and easy to understand. In Spring MVC 3.0 controller just place this code -

 @ModelAttribute("creditCardTypes")
 public Map<String,String> populateCreditCardTypes() {
        Map<String,String> creditCardTypes = new LinkedHashMap<String,String>();
        creditCardTypes.put("VS", "Visa");creditCardTypes.put("MC", "MasterCard");
        creditCardTypes.put("AE", "American Express");
        creditCardTypes.put("DS", "Discover");creditCardTypes.put("DC", "Diner's Club");                
        return creditCardTypes;
    }

Now "creditCardTypes" attribute will be avaiable in the page loading or page submitting scope , means it will available whatever the requestmapping url would be.

In jsp , place this code inside the - Credit card types:

<form:select path="creditCardType">
    <option value="Select" label="Select a card type"></option>
    <form:options items="${creditCardTypes}" />
</form:select> 

here , path="creditCardType" means the attribute in the Spring MVC model/command object, items="${creditCardTypes}" means all the populated credit card types will be available in "creditCardTypes" ModelAttribute. Thats it !!!

Answer 3

@ModelAttribute("numberList")
public List<Document> documentNumberList(){
    List<LabelValue> selectItems = new ArrayList<LabelValue>();
    List<Document> docList = documentService.retrieveAllDocumentNumbers();
    for (Document doc : docList) {
     selectItems.add(new LabelValue(doc.id,doc.value));
}
    return selectItems;
}

FYI LabelValue class is a simple DTO that we use to carry the drop down label and value items. It will have a label and value attribute, and the corresponding getters/setters.

LabelValue.java

 private String lable;
 private String value;

 //getters/setters

---- JSP -----

<tr>
    <td>DocumentNumber</td>
    <td><form:select id="docNo" path="document_number">
           <form:option value="NONE" label="--- Select ---" />
           <form:options items="${numberList}" itemValue="value" itemLabel="lable"/>
         </form:select>
    </td>
    <td><form:errors path="document_number" cssClass="error" /></td>
</tr>

hope this helps..