@ModelAttribute always maps Boolean to false

Question

when I try to map Boolean value from url to spring controller, it always map to false.

This is my url

http://localhost:8080/myurl?isFirstTime=true

here is my controller

 @RequestMapping(value = "/myurl", method = RequestMethod.GET)
        public ResponseEntity<?>  getMyUrl(@Valid @ModelAttribute MyObject ap,BindingResult bindingResult ) {

//here isFirstTime is always set to false

}

MyObj is POJO and has several other attributes which are mapping perfectly

public class Myobj{

 private boolean isFirstTime
  //there are other members as well
    //getter setter

i tried putting @JsonProperty but that also didn't work

@JsonProperty
private boolean isFirstTime

any idea what am I doing wrong here ?

you should use `POST` request instead of `GET` or use `@RequestParam boolean isFirstTime` — Hadi J, Sep 19 '18 at 16:09
see [this](https://stackoverflow.com/questions/15032063/spring-mvc-bind-request-attribute-to-controller-method-parameter) — Hadi J, Sep 19 '18 at 18:22

score 1 · Answer 1 · answered Sep 20 '18 at 04:20

With @ModelAttribute, the object will be initialized:

From the model if already added via Model.
From the HTTP session via @SessionAttributes.
From a URI path variable passed through a Converter.
From the invocation of a default constructor.
From the invocation of a "primary constructor" with arguments matching to Servlet request parameters; argument names are determined via JavaBeans

In your case, it might relative to the last statement.

You can try 2 way to solve it: - Provide the constructor with the boolean argument in Myobj.java - Add more method to initialize the @ModelAttribute Myobj firstly

@ModelAttribute
public Myobj initObj(@RequestMapping boolean isFirstTime){
     Myobj obj = new MyObj();
     obj.setIsFirstTime(isFirstTime);
     return obj;
}

score 0 · Answer 2 · answered Jan 26 '20 at 09:24

The most easiest method could be

@RequestMapping(value = "/myurl", method = RequestMethod.GET)
    public ResponseEntity<?>  getMyUrl(@Valid @ModelAttribute MyObject ap,@RequestParam boolean isFirstTime, BindingResult bindingResult ) {

//here isFirstTime is always initialized from incoming request parameters // you can set it ap.isFirstTime(isFirstTime); // or whatever your setter method is

}

score 0 · Answer 3 · answered Jan 09 '23 at 05:42

0

I stuck at this problem, but I've found that we must use Boolean object instead of boolean primitive type to map boolean value correctly in ModelAttribute

answered Jan 09 '23 at 05:42

ntv

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@ModelAttribute always maps Boolean to false

3 Answers3