Bind a set in a spring form

Question

I am trying to bind a spring form with a set in the command object.

In my command class AInstance I defined set as

private Set<BParameter> bParameters = new HashSet<BParameter>();

In jsp I bind it as

<form:input path="bParameters " />
<form:input path="bParameters " />

As its a Java Set so there may be many fields. When I submit this form I tried to get Set as:

Set<BParameter> bParameters = aInstance.getBParameters();

I got Set with a 0 size.

I also tried to bind as

<form:input path="bParameters[${itemsRow.index}].bParmvalues[0].parmValue" />

but got exception

Invalid property 'bParameters[0]' of bean class

What is the problem with my binding?

score 1 · Answer 1 · answered Jul 25 '11 at 17:16

1

Its going to be an array, which Spring will translate into a List; it will also instantiate the List implementation - you don't need to do that in your Command object. Try using

private List<String> bParameters;

public void setBParameters(List<String> bParameters) {
    this.bParameters= bParameters;
}
public List<String> getBParameters() {
    return bParameters;
}

in your Command object. Those values are probably coming in as Strings.

answered Jul 25 '11 at 17:16

atrain

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By using List<> instead of Set<> in controller. Problem solved. – Muhammad Imran Tariq Jul 28 '11 at 04:32

score 1 · Accepted Answer · answered Jul 25 '11 at 17:28

1

Use an List in the controller.

In the view you can use this straight html (not sure if this works with spring tags).

<input name="bParameters[{idx}].bParmvalues[0].parmValue" />

answered Jul 25 '11 at 17:28

Jaime Hablutzel

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1

By using List<> instead of Set<> in controller. Problem solved. – Muhammad Imran Tariq Jul 28 '11 at 04:32
3

It's more like a workaround. If you work directly on your JPA objects through the form this is not possible. It should not be necessary to workaround this but I haven't been able to find a solution – Marc Jun 16 '14 at 12:45

score 1 · Answer 3 · answered Jul 27 '11 at 11:36

1

I don't have problems binding as

 private Set<Types> typeses = new HashSet<Types>(0);


  <form:textarea path="typeses" style="width:200px;height:150px"/>

I use Spring 3.5. The only problem with this is, that it leaves []-marks on the field for some reason

answered Jul 27 '11 at 11:36

mjgirl

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I would like to know that too! :) – mjgirl Jul 28 '11 at 06:17
You mean all the fields in your form or what? – mjgirl Jul 29 '11 at 06:16
When I bind a path for a field e.g []-mark diappears. Similarly I bind my all fields and get rid of []-mark. – Muhammad Imran Tariq Jul 29 '11 at 17:18
Can you still tell me where you get itemsRow ja ParmValue attributes? Are they attributes of objects that your set hold? – mjgirl Aug 01 '11 at 10:03
I could not understand your question. itemsRow is a loop counter in jsp which can be set in for-each tag as varStatus="itemsRow">. Hope it may help you. – Muhammad Imran Tariq Aug 02 '11 at 10:04
So I think its different for me, because I use texarea. Each word written, separated with comma should be a set instance. – mjgirl Aug 03 '11 at 11:14

score 0 · Answer 4 · edited May 23 '17 at 12:12

I cannot find a way to bind Set into form parameters. However other solutions suggesting to "use list instead" is not good enough for me because if the field is part of JPA one-to-many relationship with eager fetching, using List will cause duplicates

Hence the best solution I find so far is by posting the form as JSON -- using Ajax -- instead. Here's how in JQuery:

var person = // .. construct form object here

$.ajax(url, {
  method : 'post',
  contentType : 'application/json',
  data : JSON.stringify(person)
});

Note that you need to mark the contentType as application/json

On the controller side, you can bind this to a Java object by using @RequestBody annotation:

@RequestMapping(..)
public void save(@RequestBody Person person) {
  ..
}

More info here: https://gerrydevstory.com/2013/08/14/posting-json-to-spring-mvc-controller/

Bind a set in a spring form

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