Le printemps de la Validation du Formulaire d'Erreur: java.lang.IllegalArgumentException: 'items' ne doit pas être null

Je suis en train de Validate Spring forme qui comprend:

Normal champs de saisie
Boutons Radio, dont les options sont définies dans le contrôleur (plus tard peut venir de la base de données)
Case à cocher, dont les options sont également définies dans le contrôleur de
Sélectionnez le champ qui est également définie dans le contrôleur

Modèle:

public class Student {
    private Long id;

    @NotEmpty
    private String name;

    @NotEmpty
    private String address;

    @NotEmpty
    private String contactNumber;

    @NotEmpty
    private String grade;

    @NotEmpty
    private String gender;

    @NotEmpty
    @Email
    private String email;

    @NotEmpty
    private List<String> extraSubjects = new ArrayList<String>();

    /****  Corresponding getter setters ****/

}

Contrôleur:-

@Controller
@RequestMapping("/student")
public class StudentController {
private Logger logger = Logger.getLogger(StudentController.class);
@RequestMapping("/home")
public String getHomePage() {
return "home";
}
@RequestMapping(value = "/add", method = RequestMethod.GET)
public String addStudentForm(Model model) {
Student student = new Student();
model.addAttribute("studentForm", student);
LinkedHashMap<Integer, String> gradeList = new LinkedHashMap<Integer, String>();
gradeList.put(1, "Class 1");
gradeList.put(2, "Class 2");
gradeList.put(3, "Class 3");
gradeList.put(4, "Class 4");
gradeList.put(5, "Class 5");
model.addAttribute("gradeList", gradeList);
List<String> genderList = new ArrayList<String>();
genderList.add("Male");
genderList.add("Female");
model.addAttribute("genderList", genderList);
student.setGender("Male");
List<String> extraSubjects = new ArrayList<String>();
extraSubjects.add("Math II");
extraSubjects.add("Population");
List<String> extraSubjectsStd = new ArrayList<String>();
extraSubjectsStd.add("Math II");
extraSubjectsStd.add("Population");
student.setExtraSubjects(extraSubjectsStd);
extraSubjects.add("Computer");
model.addAttribute("extraSubjects", extraSubjects);
return "addstudent";
}
@RequestMapping(value = "/add", method = RequestMethod.POST)
public String addStudent(
@Valid @ModelAttribute("studentForm") Student student,
BindingResult result) {
if (result.hasErrors()) {
logger.info("Returning add page with errors");
return "addstudent";
}
//Stuffs to save in database 
return "redirect:add";
}
}

Page JSP:-

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib uri="http://www.springframework.org/tags" prefix="spring"%>
<%@ taglib uri="http://www.springframework.org/tags/form" prefix="form"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Insert title here</title>
<style>
.error {
color: #ff0000;
}
.errorblock {
color: #000;
background-color: #ffEEEE;
border: 3px solid #ff0000;
padding: 8px;
margin: 16px;
}
</style>
</head>
<body>
<form:form action="add" method="post" commandName="studentForm">
<form:errors path="*" cssClass="errorblock" element="div" />
<table border="0">
<tr>
<td colspan="3" align="center"><h3>Add Student</h3></td>
</tr>
<tr>
<td><form:label path="name">
<spring:message code="label.studentname" />
</form:label></td>
<td><form:input path="name" /></td>
<td><form:errors path="name" cssClass="error" /></td>
</tr>
<tr>
<td><form:label path="address">
<spring:message code="label.address" />
</form:label></td>
<td><form:input path="address" /></td>
<td><form:errors path="address" cssClass="error" />
</tr>
<tr>
<td>Contact Number:</td>
<td><form:input path="contactNumber" /></td>
<td><form:errors path="contactNumber" cssClass="error" />
</tr>
<tr>
<td><form:label path="grade">
<spring:message code="label.grade" />
</form:label></td>
<td><form:select path="grade">
<form:option value="" label="--- Select ---" />
<form:options items="${gradeList}" />
</form:select></td>
<td><form:errors path="grade" cssClass="error" />
</tr>
<tr>
<td>Gender:</td>
<td><form:radiobuttons path="gender" items="${genderList}" />
</td>
<td><form:errors path="gender" cssClass="error" />
</tr>
<tr>
<td>Extra Subjects:</td>
<td><form:checkboxes items="${extraSubjects}"
path="extraSubjects" /></td>
<td><form:errors path="extraSubjects" cssClass="error" />
</tr>
<tr>
<td>Email Address:</td>
<td><form:input items="${email}" path="email" /></td>
<td><form:errors path="email" cssClass="error" />
</tr>
<tr>
<td></td>
<td align="center"><input type="submit" value="Save" /></td>
<td></td>
</tr>
</table>
</form:form>
</body>
</html>

Maintenant, Quand je lance mon application, les formes se charge pendant que je perform get operation. La valeur de la radio buttons, select fields, and checkboxes are loaded et sélectionné ainsi. Si je submit my form with no validation errors it works fine mais quand j'envoie mon formulaire with validation errors, j'obtiens les erreurs suivantes:

StackTrace:-

Jun 26, 2014 4:32:00 PM org.apache.catalina.core.ApplicationDispatcher invoke
SEVERE: Servlet.service() for servlet jsp threw exception
java.lang.IllegalArgumentException: 'items' must not be null
at org.springframework.util.Assert.notNull(Assert.java:112)
at org.springframework.web.servlet.tags.form.AbstractMultiCheckedElementTag.setItems(AbstractMultiCheckedElementTag.java:85)
at org.apache.jsp.WEB_002dINF.pages.addstudent_jsp._jspx_meth_form_005fradiobuttons_005f0(addstudent_jsp.java:810)
at org.apache.jsp.WEB_002dINF.pages.addstudent_jsp._jspService(addstudent_jsp.java:360)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:748)
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:486)
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:411)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:338)
at org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:209)
at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:266)
at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1225)
at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1012)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:876)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:931)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:833)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:646)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:807)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:313)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
DEBUG org.springframework.web.servlet.DispatcherServlet- Error rendering view [org.springframework.web.servlet.view.JstlView: name 'addstudent'; URL [/WEB-INF/pages/addstudent.jsp]] in DispatcherServlet with name 'mvc-dispatcher'
org.apache.jasper.JasperException: An exception occurred processing JSP page /WEB-INF/pages/addstudent.jsp at line 62
59:             </tr>
60:             <tr>
61:                 <td>Gender:</td>
62:                 <td><form:radiobuttons path="gender" items="${genderList}" />
63:                 </td>
64:                 <td><form:errors path="gender" cssClass="error" />
65:             </tr>    
Stacktrace:
at org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:568)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:470)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:748)
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:486)
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:411)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:338)
at org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:209)
at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:266)
at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1225)
at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1012)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:876)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:931)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:833)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:646)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:807)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:313)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.IllegalArgumentException: 'items' must not be null
at org.springframework.util.Assert.notNull(Assert.java:112)
at org.springframework.web.servlet.tags.form.AbstractMultiCheckedElementTag.setItems(AbstractMultiCheckedElementTag.java:85)
at org.apache.jsp.WEB_002dINF.pages.addstudent_jsp._jspx_meth_form_005fradiobuttons_005f0(addstudent_jsp.java:810)
at org.apache.jsp.WEB_002dINF.pages.addstudent_jsp._jspService(addstudent_jsp.java:360)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
... 42 more
Jun 26, 2014 4:32:00 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [mvc-dispatcher] in context with path [/sms] threw exception [An exception occurred processing JSP page /WEB-INF/pages/addstudent.jsp at line 62
59:             </tr>
60:             <tr>
61:                 <td>Gender:</td>
62:                 <td><form:radiobuttons path="gender" items="${genderList}" />
63:                 </td>
64:                 <td><form:errors path="gender" cssClass="error" />
65:             </tr>
Stacktrace:] with root cause
java.lang.IllegalArgumentException: 'items' must not be null
at org.springframework.util.Assert.notNull(Assert.java:112)
at org.springframework.web.servlet.tags.form.AbstractMultiCheckedElementTag.setItems(AbstractMultiCheckedElementTag.java:85)
at org.apache.jsp.WEB_002dINF.pages.addstudent_jsp._jspx_meth_form_005fradiobuttons_005f0(addstudent_jsp.java:810)
at org.apache.jsp.WEB_002dINF.pages.addstudent_jsp._jspService(addstudent_jsp.java:360)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:748)
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:486)
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:411)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:338)
at org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:209)
at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:266)
at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1225)
at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1012)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:876)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:931)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:833)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:646)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:807)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:313)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

Je suis en mesure de comprendre que le List que j'ai utilisé pour specifying genders, gradeList, extraSubjects sont semblent être NULL after post request.

Comment puis-je rendre à nouveau ces valeurs dans le formulaire après le post si la validation échoue?
Devrais-je avoir à définir la valeur dans les listes sur la méthode POST comme dans le cas de la méthode GET?

Vous pourriez mettre le studentForm dans la session. Plus simple est d'ajouter à la @SessionAttribute au Contrôleur de niveau de la classe et laissez-le Printemps le fais, c'est de la magie.
qu'entendez-vous par avec validation errors ?
Je veux dire, si le formulaire contient des erreurs de validation, j'obtiens l'erreur ci-dessus. Les erreurs de Validation reportez-vous à la contrainte n'est pas satisfaisant dans le modèle.
Si j'utilise @sessionAttribute, n'est-ce pas affecter lors de l'ajout/modification de différents étudiants dans plusieurs onglets que les deux d'entre eux ont même session?

OriginalL'auteur Chandra Prakash | 2014-06-26

Dans vous obtenez une partie, vous remplissez votre modèle, pas seulement avec studentForm mais aussi avec genderList, gradeList et extraSubjects. Et vous utilisez dans votre jsp.

Dans le post de la partie, vous avez un studentForm initialisé par les paramètres dans la requête. Mais votre ne jamais initialiser les listes. Ainsi, dans la JSP, ${gradeList}, ${genderList} et ${extraSubjects} et tous nuls, alors l'erreur.

Vous devez les initialiser les trois listes en addStudent avant de les transmettre à la vue, si la validation échoue. Vous pouvez le faire soit proposé par Neil McGuigan, c'est à dire en ayant printemps pour remplir automatiquement le modèle, ou par le remplissage de vous-même. Par exemple, vous pourriez avoir :

void initLists(Model model) {
LinkedHashMap<Integer, String> gradeList = new LinkedHashMap<Integer, String>();
gradeList.put(1, "Class 1");
gradeList.put(2, "Class 2");
gradeList.put(3, "Class 3");
gradeList.put(4, "Class 4");
gradeList.put(5, "Class 5");
model.addAttribute("gradeList", gradeList);
List<String> genderList = new ArrayList<String>();
genderList.add("Male");
genderList.add("Female");
model.addAttribute("genderList", genderList);
List<String> extraSubjects = new ArrayList<String>();
extraSubjects.add("Math II");
extraSubjects.add("Population");
extraSubjects.add("Computer");
model.addAttribute("extraSubjects", extraSubjects);
}

et appel initLists à la fois dans addStudentForm et dans addStudent. Exemple de code pour la fin :

@RequestMapping(value = "/add", method = RequestMethod.POST)
public String addStudent(
@Valid @ModelAttribute("studentForm") Student student,
BindingResult result, Model model) {
if (result.hasErrors()) {
logger.info("Returning add page with errors");
initLists(model);
return "addstudent";
}
//Stuffs to save in database 
return "redirect:add";
}

Bien sûr, tous initialisation de la liste devrait être retiré de addStudentForm une fois que vous appelez initLists à partir de là ...

Merci, Ça a fonctionné pour moi.

OriginalL'auteur Serge Ballesta

Changement de votre contrôleur pour être comme ceci:

@Controller
@RequestMapping("/student")
@SessionAttributes({"studentForm", "gradeList", "genderList", "extraSubjects"})
public class StudentController {
private Logger logger = Logger.getLogger(StudentController.class);
@ModelAttribute("studentForm")
Student getStudent() {
Student student = new Student();
student.setGender("Male");
List<String> extraSubjectsStd = new ArrayList<String>();
extraSubjectsStd.add("Math II");
extraSubjectsStd.add("Population");
student.setExtraSubjects(extraSubjectsStd);
return student;
}
@ModelAttribute("gradeList")
GradeList getGradeList() {
LinkedHashMap<Integer, String> gradeList = new LinkedHashMap<Integer, String>();
gradeList.put(1, "Class 1");
gradeList.put(2, "Class 2");
gradeList.put(3, "Class 3");
gradeList.put(4, "Class 4");
gradeList.put(5, "Class 5");
return gradeList;
}
@ModelAttribute("genderList")
List<String> getGenderList() {
List<String> genderList = new ArrayList<String>();
genderList.add("Male");
genderList.add("Female");
return genderList;
}
@ModelAttribute("extraSubjects")
List<String> getExtraSubjects() {
List<String> extraSubjects = new ArrayList<String>();
extraSubjects.add("Math II");
extraSubjects.add("Population");
extraSubjects.add("Computer");
return extraSubjects;
}
@RequestMapping("/home")
public String getHomePage() {
return "home";
}
@RequestMapping(value = "/add", method = RequestMethod.GET)
public String addStudentForm() {
return "addstudent";
}
@RequestMapping(value = "/add", method = RequestMethod.POST)
public String addStudent(
@Valid @ModelAttribute("studentForm") Student student,
BindingResult result,
SessionStatus sessionStatus) {
if (result.hasErrors()) {
logger.info("Returning add page with errors");
return "addstudent";
}
sessionStatus.setComplete();
//Stuffs to save in database 
return "redirect:add";
}
}

Pendant que nous y sommes:

Vos données comme gradeList devrait probablement être dans une base de données.
étudiant/URL /étudiants
Page d'accueil doit être dans son propre contrôleur

Ce n' StudentForm représente? Est-il différent de la Classe pour la forme uniquement? de quoi ça ressemble?

OriginalL'auteur Neil McGuigan

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