'Spring MVC + thymeleaf: How to allow empty input?

How can I allow empty input to field with type long in Spring MVC + thymeleaf?

I want this field to take default value. Currently I have the error:

Field error in object 'greeting' on field 'id': rejected value []; codes [typeMismatch.greeting.id,typeMismatch.id,typeMismatch.long,typeMismatch]; arguments [org.springframework.context.support.DefaultMessageSourceResolvable: codes [greeting.id,id]; arguments []; default message [id]]; default message [Failed to convert property value of type 'java.lang.String' to required type 'long' for property 'id'; nested exception is java.lang.NumberFormatException: For input string: ""]]

when I try to submit form with empty id field

<!DOCTYPE HTML>
<html xmlns:th="http://www.thymeleaf.org">
<head> 
    <title>Getting Started: Handling Form Submission</title>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
</head>
<body>
    <h1>Form</h1>
    <form action="#" th:action="@{/greeting}" th:object="${greeting}" method="post">
        <p>Id: <input type="text" th:field="*{id}" /></p>
        <p>Message: <input type="text" th:field="*{content}" /></p>
        <p><input type="submit" value="Submit" /> <input type="reset" value="Reset" /></p>
    </form>
</body>
</html>

My POJO:

public class Greeting {

    private long id;
    private String content;

    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }

    public String getContent() {
        return content;
    }

    public void setContent(String content) {
        this.content = content;
    }

}

My controller:

@Controller
public class GreetingController {

    @GetMapping("/greeting")
    public String greetingForm(Model model) {
        model.addAttribute("greeting", new Greeting());
        return "greeting";
    }

    @PostMapping("/greeting")
    public String greetingSubmit(@ModelAttribute Greeting greeting) {
        return "result";
    }
}

Solution 1:^[1]

Had the same exact problem, fixed it using wrapper objects (Integer instead of int, Double instead of double, etc) in the POJO model classes.

Thanks Metroids for answer.

Sources

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Source: Stack Overflow

Solution	Source
Solution 1	Gonzalinho

'Spring MVC + thymeleaf: How to allow empty input?

Solution 1:[1]

Sources

Related Questions

Solution 1:^[1]