java - Unable to get updated values in a dynamically created form using Spring Boot and Thymeleaf -

i have created dynamic form in thymeleaf populates feedbacks users in table format on ui. form first called when api of controller gets hit. relevant code same given below :

allfeedbacks.html

<h2>dynamic form</h2> <form action="#" th:action="@{/updatefb}" th:object="${feedbacklist}"     method="post">     <table>         <tr>             <th>message</th>             <th>status</th>             <th>comments</th>         </tr>         <tr th:each="feedback : ${feedbacklist.myfblist}">             <td th:text="${feedback.message}" th:field="${feedback.message}">the                 first name</td>             <td><select>                     <option value="pending"                         th:selected="${feedback.status == 'pending'}">pending</option>                     <option value="in process"                         th:selected="${feedback.status == 'in process'}">in                         process</option>                     <option value="done" th:selected="${feedback.status == 'done'}">done</option>             </select></td>             <td><input type="text" placeholder="enter comment here"                 name="comments" th:text="${feedback.comment}"                 th:field="${feedback.comment}" /></td>         </tr>     </table>     <button type="submit">submit</button> </form> 

basically have created 2 beans, 1 feedback.java bean while other feedbacklist.java bean. code same given below :

feedback.java

@entity @table(name = "feedback") public class feedback implements serializable {  private static final long serialversionuid = -3009157732242241606l;  @id  private string id;  public string getid() {     return id; }  public string getmessage() {     return message; }  public string getstatus() {     return status; }  public string getcomment() {     return comment; }  @column(name = "message") private string message;  @column(name = "status") private string status;  @column(name = "comment") private string comment;  public feedback() { }  public feedback(string message, string status) {     this.message = message;     this.status = status;     this.id = uuid.randomuuid().tostring();      } 

feedbacklist.java

public class feedbacklist {  arraylist<feedback> myfblist;  public arraylist<feedback> getmyfblist() {     return myfblist;    }  public void setmyfblist(arraylist<feedback> myfblist) {     this.myfblist = myfblist;    } } 

relevant code controller class follows :

    @requestmapping(value = "/getall", method = requestmethod.get)     public string getallfeedbacks(@valid feedbacklist feedbacklist,      bindingresult bindingresult, model model) {      arraylist<feedback> fbarray = new arraylist<>();     (feedback fb : repository.findall()) {         fbarray.add(fb);         }     feedbacklist.setmyfblist(fbarray);     model.addattribute("feedback", new feedback());     model.addattribute("feedbacklist", feedbacklist);     return "allfeedbacks";     }      @requestmapping(value = "/updatefb", method = requestmethod.post)     public string updatefbstatus(@valid feedbacklist feedbacklist,      bindingresult      bindingresult, model model) {      //feedbacklist coming null below     (feedback fb : feedbacklist.getmyfblist()) {         system.out.println(fb.getcomment());         system.out.println(fb.getmessage());         system.out.println(fb.getstatus());         }     // code update database new status , comment go     // here     return "result";    } 

the form getting rendered on ui when fire request, however, when make changes in form , submit ( post ), feedbacklist coming null. please guide me ?

to use list inside form thymeleaf little bit more tricky, need use specific syntax, here show example.

<tr th:each="feedback : ${feedbacklist.myfblist}">     <td th:field="*{myfblist[__${feedbackstat.index}__].message}">the         first name     </td>     ...//same others fields </tr> 

in thymeleaf have use stat object array position want set value, normal fields inside object have use '*' notation.