Spring MVC Constraint Validator Annotation:
Spring mvc custom validator annotation with constraint validator example interface using maven and eclipse.
package com.candidjava.spring.bean;
import java.util.List;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;
import com.candidjava.spring.validator.Email;
import com.candidjava.spring.validator.Phone;
public class User
{
@NotNull
@Size(min=1)
private String name;
@NotNull
@Size(min=1)
private List<String> language;
@Size(min=1)
private String country;
@NotNull
private String gender;
@Size(min=8, max=20)
private String password;
@Phone
private String phone;
public String getPhone() {
return phone;
}
public void setPhone(String phone) {
this.phone = phone;
}
@Email
@Size(min=1)
private String email;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public List<String> getLanguage() {
return language;
}
public void setLanguage(List<String> language) {
this.language = language;
}
public String getCountry() {
return country;
}
public void setCountry(String country) {
this.country = country;
}
public String getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
}
Spring constraintValidator
Phone.java
package com.candidjava.spring.validator;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import javax.validation.Constraint;
import javax.validation.Payload;
@Documented
@Constraint(validatedBy = EmailConstraintValidator.class)
@Target({ElementType.METHOD,ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
public @interface Email
{
String message() default "{Email}";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
}
PhoneValidator.java
package com.candidjava.spring.validator;
import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;
public class PhoneValidator implements ConstraintValidator<Phone, String> {
@Override
public void initialize(Phone paramA) {
}
@Override
public boolean isValid(String phoneNo, ConstraintValidatorContext ctx) {
if(phoneNo == null){
return false;
}
//validate phone numbers of format "1234567890"
if (phoneNo.matches("\\d{10}")) return true;
//validating phone number with -, . or spaces
else if(phoneNo.matches("\\d{3}[-\\.\\s]\\d{3}[-\\.\\s]\\d{4}")) return true;
//validating phone number with extension length from 3 to 5
else if(phoneNo.matches("\\d{3}-\\d{3}-\\d{4}\\s(x|(ext))\\d{3,5}")) return true;
//validating phone number where area code is in braces ()
else if(phoneNo.matches("\\(\\d{3}\\)-\\d{3}-\\d{4}")) return true;
//return false if nothing matches the input
else return false;
}
}
Email.java
package com.candidjava.spring.validator;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import javax.validation.Constraint;
import javax.validation.Payload;
@Documented
@Constraint(validatedBy = EmailConstraintValidator.class)
@Target({ElementType.METHOD,ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
public @interface Email
{
String message() default "{Email}";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
}EmailConstraintValidator.java
package com.candidjava.spring.validator;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import javax.validation.Constraint;
import javax.validation.Payload;
@Documented
@Constraint(validatedBy = EmailConstraintValidator.class)
@Target({ElementType.METHOD,ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
public @interface Email
{
String message() default "{Email}";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
}
Spring Controller
package com.candidjava.spring.controller;
import javax.validation.Valid;
import org.springframework.stereotype.Controller;
import org.springframework.validation.BindingResult;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.servlet.ModelAndView;
import com.candidjava.spring.bean.User;
@Controller
public class UserController {
User users = new User();
@GetMapping("index")
public ModelAndView register(User user) {
return new ModelAndView("register");
}
@PostMapping("/register")
public ModelAndView create(@Valid User user, BindingResult bindingResult) {
ModelAndView model = new ModelAndView("view");
// user bean will be automatically binded to view refer @ModelAttribute
if(bindingResult.hasErrors())
{
return new ModelAndView("register");
}
users.setName(user.getName());
users.setEmail(user.getEmail());
users.setGender(user.getGender());
users.setLanguage(user.getLanguage());
users.setCountry(user.getCountry());
users.setPassword(user.getPassword());
return model;
}
@GetMapping("/register")
public ModelAndView viewData(User user) {
ModelAndView model = new ModelAndView("register");
return model;
}
}Spring Resource file:
Size.user.name = please enter name NotNull.user.gender = Please specify your gender Size.user.country = Please select your country Size.user.language= Please select at least one language Size.user.password = password must be between 8 and 20 Size.user.email=Email field can't be blank typeMismatch=Invalid format Email=please enter valid email address Phone=please enter Valid phone number
JSP view
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%@taglib prefix="form" uri="http://www.springframework.org/tags/form"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<style type="text/css">
.err
{
color:red;
}
</style>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<h2>Simple spring form handling</h2>
<form:form action="register" method="POST" modelAttribute="user">
Name:<form:input path="name"/><p><form:errors path="name" class="err"/></p><br>
Gender : Male<form:radiobutton name="gender" value="male" path="gender"/> Female<form:radiobutton name="gender" value="female" path="gender"/><p><form:errors path="gender" class="err"/></p><br>
Email : <form:input path="email"/><p><form:errors path="email" class="err"/></p><br>
Phone : <form:input path="phone"/><p><form:errors path="phone" class="err"/></p><br>
Languages : English<form:checkbox value="english" path="language" /> French<form:checkbox value="french" path="language"/> Tamil<form:checkbox value="tamil" path="language"/><p><form:errors path="language" class="err"/></p><br>
Country : <form:select path="country">
<form:option value="">select country</form:option>
<form:option value="india">INDIA</form:option>
<form:option value="usa">USA</form:option>
<form:option value="china">CHINA</form:option>
</form:select>
<p><form:errors path="country" class="err"/></p>
<br>
Password:<form:password path="password"/><p><form:errors path="password" class="err"/></p><br>
<input type="submit" value="submit" />
</form:form>
</body>
</html>Screenshot:
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