BindingResult object has not errors-CodePudding

I've the following code

Object

package com.example.demo;
import javax.validation.constraints.*;

public class Customer {

    @NotEmpty(message="first name should contain a value")
    private String firstName;
    
    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    
}

Controller

package com.example.demo;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import javax.servlet.http.HttpServletRequest;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.validation.BindingResult;
import javax.validation.Valid;

@Controller
@RequestMapping("/customer")
public class CustomerController {

    private static int counter = 0;

 
    @RequestMapping("/showForm")
    public String showForm(Model model) {
        model.addAttribute("customer", new Customer());
        return "customer-form";
    }

    @RequestMapping("/processForm")
    public String processForm(@Valid @ModelAttribute("customer") Customer customer, BindingResult bindingResult) {
        return "customer-form";
    }

}

Form in a jsp file

<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %>
    <html>

    <head></head>

    <body>
        <form:form method="POST" action="processForm" modelAttribute="customer">
            <form:label path="firstName">Name</form:label>
            <form:input path="firstName" />
            <form:errors path="firstName"/>
            <button type="submit">Submit</button>
        </form:form>
    </body>

    </html>

I've done some debugging and when I click the submit button the method processForm is called correctly, but the bindingResult has no errors. The firstName variable is empty. Why validation is not working?

CodePudding user response：

Make sure that you've declared Hibernate Validator dependency in the pom.xml (if you use maven)

<dependency>
    <groupId>org.hibernate.validator</groupId>
    <artifactId>hibernate-validator</artifactId>
    <version>7.0.4.Final</version>
</dependency>

Validation constraints can be in your classpath from other libs, but validation processor being in dependency above