Spring Validator for duplicate record in database - spring

Question

In my page jsp, i have a form where i can add a user to my database, and i use a validator to show errors when fields are empty, but what i want to do is, when i insert a duplicate entry of the primary key of my table, the validator show me a message that this login for example is already taken instead having an error by Apache!
this is my User POJO :
package gestion.delegation.domaine;
import java.io.Serializable;
public class User implements Serializable{
/**
*
*/
private static final long serialVersionUID = 1L;
int id;
String nom;
String prenom;
String login;
String password;
String role;
boolean enable;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getNom() {
return nom;
}
public void setNom(String nom) {
this.nom = nom;
}
public String getPrenom() {
return prenom;
}
public void setPrenom(String prenom) {
this.prenom = prenom;
}
public String getLogin() {
return login;
}
public void setLogin(String login) {
this.login = login;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public boolean getEnable() {
return this.enable;
}
public void setEnable(boolean enable) {
this.enable = enable;
}
public User(int id, String nom, String prenom, String login,
String password, String role, boolean enable) {
super();
this.id = id;
this.nom = nom;
this.prenom = prenom;
this.login = login;
this.password = password;
this.role = role;
this.enable = enable;
}
public String getRole() {
return role;
}
public void setRole(String role) {
this.role = role;
}
public User() {
super();
}
}
and this is my validator :
package gestion.delegation.validator;
import gestion.delegation.domaine.User;
import org.springframework.validation.Errors;
import org.springframework.validation.ValidationUtils;
import org.springframework.validation.Validator;
public class AddUserValidator implements Validator{
#Override
public boolean supports(Class<?> clazz) {
return User.class.isAssignableFrom(clazz);
}
#Override
public void validate(Object obj, Errors err) {
ValidationUtils.rejectIfEmptyOrWhitespace(err, "nom", "name.required","Choisissez un nom");
ValidationUtils.rejectIfEmptyOrWhitespace(err, "prenom", "prenom.required", "Choisissez un prenom");
ValidationUtils.rejectIfEmptyOrWhitespace(err, "login", "login.required", "Choisissez un login");
ValidationUtils.rejectIfEmptyOrWhitespace(err, "password", "password.required", "Choisissez un password");
ValidationUtils.rejectIfEmpty(err, "role", "role.required", "Choisissez un role");
}
}
the form :
<c:if test="${not empty msg_success}">
<div class="success">Vous avez ajouter un utilisateur avec
succès !</div>
</c:if>
<form:form name="ajf"
action="${pageContext.request.contextPath}/ajouter_user"
method="post" commandName="user">
<table id="tabmenu">
<tr>
<td id="idtab">Nom :</td>
<td><form:input type="text" path="nom"
class="round default-width-input" name="name_" /></td>
<td><form:errors path="nom" Class="errorbox" /></td>
</tr>
<tr>
<td id="idtab">Prénom :</td>
<td><form:input type="text" path="prenom" name="prenom_"
class="round default-width-input" /></td>
<td><form:errors path="prenom" cssClass="errorbox" />
</tr>
<tr>
<td id="idtab">Login :</td>
<td><form:input type="text" path="login" name="login_"
cssClass="round default-width-input" /></td>
<td><form:errors path="login" cssClass="errorbox" /></td>
</tr>
<tr>
<td id="idtab">Password :</td>
<td><form:input type="password" path="password" name="pass_"
class="round default-width-input" /></td>
<td><form:errors path="password" cssClass="errorbox" /></td>
</tr>
<tr>
<td id="idtab">Séléctionner un rôle :</td>
<td><form:select path="role">
<form:option value="" label="" />
<form:option value="ROLE_ADMIN">Administrateur</form:option>
<form:option value="ROLE_USER">Simple utilisateur</form:option>
</form:select></td>
<td><form:errors path="role" cssClass="errorbox" /></td>
</tr>
<tr>
<td id="idtab">Activé :</td>
<td><form:input type="checkbox" value="true" path="enable" />
Oui</td>
</tr>
<tr></tr>
<tr></tr>
<tr>
<td><input
class="button round blue image-right ic-right-arrow"
type="submit" value="Créer" /></td>
<td><input
class="button round blue image-right ic-right-arrow"
type="reset" value="Initialiser" /></td>
</tr>
</table>
</form:form>
Any Idea?

Answer 1

I'm afraid that a Validator will not be sufficient in this case. Although you could extend your AddUserValidator class to check whether the given user name is free, it will not
work in a situation in which two users simultaneously try to register using the same user name - the validation will pass, however one of the users will get an error from the database.
To protect yourself against such situations I would place the registration logic in a try catch block and in case of an error display a proper message to the user. This would be kind of an application-level validation.

Answer 2

Spring validator simply checks your object in accordance with the prescribed rules before you bring it into the database. It does not know anything about the database. To display the error that occurred while working with a database, you need to catch the exception manually.

Answer 3

In your Controller Just Check the duplication by querying from Model Repository.
#Model Entity
#Table(name = "people")
public class People {
#Column(name = "nic")
#NotEmpty(message = "*Please provide your nic")
private String nic;
#Repository
public interface PeopleRepository extends JpaRepository<People, Integer>{
People findByNic(String nic);
}
#Controller
#RequestMapping(value = "/welcome", method = RequestMethod.POST)
public ModelAndView createNewPeople(Model model,, BindingResult bindingResult) {
ModelAndView modelAndView = new ModelAndView();
People peopleExistsEmail = peopleService.findUserByNic(people.getNic());
if (peopleExistsEmail != null) {
bindingResult
.rejectValue("nic", "error.people",
"There is already a person registered with the nic provided");
}
if (bindingResult.hasErrors()) {
modelAndView.setViewName("welcome");
} else {
peopleService.savePeople(people);
modelAndView.addObject("successMessage", "People has been registered successfully");
modelAndView.addObject("people", new People());
} catch (Exception e) {
e.printStackTrace();
}
}
return modelAndView;
}

Answer 4

So this is the Right Answer :
The method in DAO class implementation is like that :
public boolean AddUser(User user) {
boolean t=true;
final String User_INSERT1 = "insert into utilisateurs (login, password, nom, prenom,enable) "
+ "values (?,?,?,?,?)";
final String User_INSERT2="insert into roles (login,role) values(?,?)";
/*
* On récupère et on utilisera directement le jdbcTemplate
*/
MessageDigestPasswordEncoder encoder = new MessageDigestPasswordEncoder("SHA");
String hash = encoder.encodePassword(user.getPassword(), "");
final String check ="select count(*) from utilisateurs where login = ?";
int result= getJdbcTemplate().queryForInt(check, new Object[]{String.valueOf(user.getLogin())});
if (result==0) {
getJdbcTemplate()
.update(User_INSERT1,
new Object[] {user.getLogin(),
hash, user.getNom(),
user.getPrenom(), user.getEnable(),
});
getJdbcTemplate().update(User_INSERT2, new Object[]{user.getLogin(),user.getRole()});
return t;
}
else { t = false ; return t;}
}
The controller :
#RequestMapping(value ="/ajouter_user", method = RequestMethod.POST)
public String add(#ModelAttribute User us,BindingResult result,ModelMap model) {
AddUserValidator uservalid=new AddUserValidator();
uservalid.validate(us, result);
if (result.hasErrors()) {
model.addAttribute("usersystem", userservice.getAllUsers());
return "gestionUser";
}else {
boolean e = userservice.AddUser(us);
if (e==false){
model.addAttribute("msg_failed","true");
}
else {
model.addAttribute("msg_success","true");}
model.addAttribute("usersystem", userservice.getAllUsers()); /*verifier*/
return "gestionUser";
}
}
And for showing the error in the jsp file :
<c:if test="${not empty msg_failed}">
<div class="errorblock">Il existe déjà un utilisateur avec cet login </div>
</c:if>

Answer 5

The method in DAO class implementation is like that :
public final long insert(final User user) throws MyException {
String sql = "INSERT INTO users ....";
String chkSql = "SELECT count(*) FROM users WHERE username=:username";
Map namedParams = new HashMap();
namedParams.put("username", user.getUsername());
long newId = namedTemplate.queryForInt(chkSql, namedParams);
if (newId > 0) {
try {
throw new MyException(-1);
} catch (MyException e) {
throw e;
}
}
newId = ...;// could be generated if not inc field or triggered...
namedParams.put("username", user.getUserName());
...
...
namedParams.put("id", newId);
namedTemplate.update(sql, namedParams);
return newId;
}
MyException like that:
public class MyException extends Exception{
private static final long serialVersionUID = 1L;
int a;
public MyException(int b) {
a=b;
}
}
Controller:
#RequestMapping(value = "/user", method = RequestMethod.POST)
public final ModelAndView actionUser(
final ModelMap model,
#ModelAttribute("myitemuser") #Valid final User user,
final BindingResult bindResult,
...);
...
try {
userService.addUser(user); // or dao... ;)
} catch (Exception e) {
UserValidator userValidator = new UserValidator();
userValidator.custError(bindResult);
}
UserValidator like that:
...
#Override
public final void validate(final Object object, final Errors errors) {
User user = (User) object;
...
if (user.getPassword().isEmpty()) {
errors.rejectValue("password", "error.users.emptypass");
}
}
public final void custError(final Errors errors){
errors.rejectValue("username"/* or login */, "error.users.uniqname");
}
...
Ну как то так))))