bindFromRequest() 在 play framework 2.0 中不工作。 表单值始终为 null

Question

The problem is that, I can not read values in submitted form in play framework 2.0. The value is always null,

Here is my code:

my model file

 package model;

 public class Paper {
    public String query;
 }

my index.scala.html

@(myform: Form[model.Paper])

@helper.form(action =routes.Application.newPaper()) {
   myvalue:  @helper.inputText(myform("query"))  <br><br>
   <br><input type="submit">
}

conf/routes

 POST     /newkey                  controllers.Application.newPaper()
 GET     /                           controllers.Application.index()

my Application.java

  public static Result index() {
    Paper paper = new Paper();
    paper.query = "initial value";
    Form<Paper> paperForm =  Form.form(Paper.class).fill(paper);
    return ok(index.render(paperForm);
  }

  public static Result newPaper() {
    Form<Paper> paperForm = Form.form(Paper.class).bindFromRequest();
    if (!paperForm.hasErrors()) {
        Paper paper = paperForm.get();
        Logger.info("query= " + paper.query); //why I always get "query= null" ???
    }
    return redirect(routes.Application.index()); 
 }

When I visit the html page, I can not see "initial value" in the text inputbox. When I fill the inputbox and click submit button, The printed log is always: query= null

I also monitored using chrome devtool. I saw post http request was sent. But the finial status code is 303, instead of 200.

If I use DynamicForm to process the submitted form in newPaper(), then I can read the query value as expected. But Why current code does not work?

Thanks for help!

Answer 1

You need to specify method attribute as well in form tag with value post. But helper method doesn't support method attribute. So do it this way.

@(myform: Form[model.Paper])

<form method="POST" action ="@routes.Application.newPaper()"> 
   query:  @helper.inputText(myform("query"))  <br><br>
   <br><input type="submit">
</form>

Answer 2

I have used formFactory instead of Forms .

Add .withDirectFieldAccess(true); in myApplication.java for bindFormRequest .

So your code should be:

Form<Paper> paperForm = Form.form(Paper.class).bindFromRequest().withDirectFieldAccess(true);

Instead of:

Form<Paper> paperForm = Form.form(Paper.class).bindFromRequest();

By this you can get all the fields. You can find more help on this link - https://www.playframework.com/documentation/2.7.x/JavaForms

Answer 3

I had encountered this problem even in 2022.

I am using version 2.8.x, and here are the solutions I had found.

Case 1.

If you have written setters in your model, the fields with setters will be filled automatically, and you should not have any problem.

Case 2.

If you don't have setters in your model, you should use the following line: Form.form(Paper.class).withDirectFieldAccess(true).bindFromRequest(reqeust);

The position where you put withDirectFieldAccess(true) matters in version 2.8.x, and you also have to pass the request object as the argument.