How to use <form:input> for NOT form object

Spring tag <form:input> can generate <input> tag with id and name attributes. I think this feature is useful and I want to use this when using non form object. Please take a look at codes below.

"dto" object is added to "model" object as well as "form" then I want to generate id attribute automatically. However, <form:input> tag seems to be able to use for binding form object. Do I have to make a custom tag in order to realize the similar feature? Any help will be appreciated?

[Controller]

@RequestMapping(method = RequestMethod.GET)
public String show(Model model, HttpServletRequest request) {


    SampleForm form = new SampleForm();
    form.setName("Name of Form Object");

    SampleDto dto = new SampleDto();
    dto.setName("Name of Dto Object");

    model.addAttribute("form", form);
    model.addAttribute("dto", dto);

    return "sample/input";

}

[JSP]

<body>
<form:form modelAttribute="form" method="post">

    <%-- Generate with id attribute like <input id="name" name="name" type="text" value="Name of Form Object"/>  --%>
    <form:input path="name" />

    <%-- I tried below but an error occured--%>
    <%-- <form:input path="${dto.name}" /> --%>

    <%-- Just a String display like "Name of Dto Object" --%>
    ${dto.name}

    <input type="submit" name="register" value="register" />
</form:form>
</body>

[Form]
public class SampleForm {

    private String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

[Dto]
public class SampleDto {

    private String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

}

Solution

A form can only have one backing object. In your example the backing object is an instance of SampleForm. You could add a reference to a SampleDto instance in your SampleForm class:

public class SampleForm {
  private String name;
  private SampleDto dto;
  public String getName() {
     return name;
  }
  public void setName(String name) {
     this.name = name;
  }
  public SampleDto getDto() {
     return dto;
  }
  public void setDto(SampleDto dto) {
     this.dto = dto;
  }
}

Then you could do this in your JSP:

<form:input path="dto.name"/>