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 me so I'm hoping someone here can help me out.
Here is my controller:
@Controller
@RequestMapping("/document-revision")
public class DocumentRevisionController {
@Autowired
private DocumentRevisionService documentRevisionService;
private DocumentService documentService;
@RequestMapping(value="/list", method=RequestMethod.GET)
public String getDocumentRevisionList(Model model) {
List<DocumentRevision> documentRevisions = documentRevisionService.retrieveAllDocumentRevisions();
model.addAttribute("documentRevisions", documentRevisions);
return "document-revision";
}
@RequestMapping(value="/add", method=RequestMethod.GET)
public String getDocumentRevision(Model model) {
DocumentRevision documentRevision = new DocumentRevision();
model.addAttribute("documentRevisionAttribute", documentRevision);
return "new-documnent-revision";
}
@RequestMapping(value="/add", method=RequestMethod.POST)
public String postDocumentRevision(@ModelAttribute("documentRevisionAttribute") @Valid DocumentRevision documentRevision, BindingResult result) {
if(result.hasErrors()){
return "new-document-revision";
}
documentRevisionService.createDocumentRevision(documentRevision);
return "redirect:/testapp/document-revision/list";
}
}
and here is the jsp page:
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ taglib uri="http://www.springframework.org/tags/form" prefix="form" %>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
<style>
.error { color: red; }
</style>
</head>
<body>
<h1>Create New Document Revision</h1>
<c:url var="saveUrl" value="/testapp/document-revision/add" />
<form:form modelAttribute="documentRevisionAttribute" method="POST" action="${saveUrl}">
<table>
<tr>
<td>DocumentNumber</td>
<td><form:select path="document_number">
<form:option value="NONE" label="--- Select ---" />
<form:options items="${documentNumberList}" />
</form:select>
</td>
<td><form:errors path="document_number" cssClass="error" /></td>
</tr>
<tr>
<td><form:label path="documentRState">Document R-State</form:label></td>
<td><form:input path="documentRState"/></td>
<td><form:errors path="documentRState" cssClass="error"/></td>
</tr>
</table>
<input type="submit" value="Save" />
</form:form>
</body>
</html>
I have tried adding a @ModelAttribute method which retrieves the document numbers,
@ModelAttribute
public List<Document> documentNumberList(){
return documentService.retrieveAllDocumentNumbers();
}
but it gave me errors. Is there anyone who knows how it should be done?
Thank you for your time
/D
Edit I thought I'd clarify that my wish is to have a dropdown box for the document numbers which are retrieved by the documentService.
Edit 2 Here is the error log as requested:
java.lang.NullPointerException
testapp.controller.DocumentRevisionController.documentNumberList(DocumentRevisionController.java:33)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:601)
org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:212)
org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:126)
org.springframework.web.method.annotation.ModelFactory.invokeModelAttributeMethods(ModelFactory.java:123)
org.springframework.web.method.annotation.ModelFactory.initModel(ModelFactory.java:97)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:614)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:578)
org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:900)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:827)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882)
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:778)
javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
Solution I thought I would add the complete controller code that works in case there are others who could benefit from it:
@Controller
@RequestMapping("/document-revision")
public class DocumentRevisionController {
@Autowired
private DocumentRevisionService documentRevisionService;
@Autowired
private DocumentService documentService;
@RequestMapping(value="/list", method=RequestMethod.GET)
public String getDocumentRevisionList(Model model) {
List<DocumentRevision> documentRevisions = documentRevisionService.retrieveAllDocumentRevisions();
model.addAttribute("documentRevisions", documentRevisions);
return "document-revision";
}
@RequestMapping(value="/add", method=RequestMethod.GET)
public String getDocumentRevision(Model model) {
DocumentRevision documentRevision = new DocumentRevision();
model.addAttribute("documentRevisionAttribute", documentRevision);
model.addAttribute("documentNumberList", documentService.retrieveAllDocumentNumbers());
return "new-documnent-revision";
}
@RequestMapping(value="/add", method=RequestMethod.POST)
public String postDocumentRevision(@ModelAttribute("documentRevisionAttribute") @Valid DocumentRevision documentRevision, BindingResult result) {
if(result.hasErrors()){
return "new-document-revision";
}
documentRevisionService.createDocumentRevision(documentRevision);
return "redirect:/testapp/document-revision/list";
}
}
See Question&Answers more detail:
os 
