@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

}

@ModelAttribute always maps Boolean to false

2 Answers2