[英]Can't show error message after failed spring mvc form validation
我在商業模式上上課:
public class User {
@Size(min = 3, max = 20, message = "Username must be between 3 and 20 characters long")
@Pattern(regexp = "^[a-zA-Z0-9]+$", message = "Username must be alphanumeric with no spaces")
@Column(name = "name")
private String name;
@Id
@GeneratedValue
@Column(name = "user_id")
private Long userID;
@OneToMany(cascade = CascadeType.ALL)
@JoinTable(name = "userDic", joinColumns = { @JoinColumn(name = "user_id", referencedColumnName = "user_id") }, inverseJoinColumns = {
@JoinColumn(name = "acc_id", referencedColumnName = "acc_id") })
@LazyCollection(value = LazyCollectionOption.FALSE)
private Set<Account> allAccounts; //............. //constructors , setters , getters here
在新用戶的jsp輸入中,通過spring形式發生:
<form:form method="post" action="AddUser" modelAttribute="user">
<table>
<tr>
<td><form:label path="name">First Name</form:label></td>
<td><form:input path="name" /></td>
<td><form:errors path="*" /></td>
</tr>
<tr>
<td colspan="2"><input type="submit" value="Add User" /></td>
</tr>
</table>
</form:form>
這是處理此jsp的控制器:
@Controller
@SessionAttributes
public class AdminServlet
{
/* private UserValidator validator;
@InitBinder("user")
protected void initBinder(WebDataBinder binder)
{
binder.setValidator(validator);
}*/
@RequestMapping(value = "/")
public ModelAndView showUsers() throws ClassNotFoundException, SQLException
{
ModelAndView mav = new ModelAndView();
mav.setViewName("index");
mav.addObject("ATMUsers", MainService.getAllUsers());
mav.addObject("user", new User());
return mav;
}
@RequestMapping(value = "/AddUser", method = RequestMethod.POST)
public String AddUser(@ModelAttribute("user") @Valid User user, BindingResult result)
{
if (!result.hasErrors())
MainService.AddUser(user);
return "redirect:/";
}
}
驗證正確進行了字段name
。 但是控制器只是重新加載頁面,我看不到任何類型的錯誤消息。
如果我取消對控制器中有關UserValidator
和InitBinder
代碼的注釋,則會出現錯誤,但不是<form:errors path="*" />
文本,而是Java異常
javax.validation.ConstraintViolationException:在組[javax.validation.groups.Default,]的持續時間內,對類[com.antonbanking.business.User]的驗證失敗
問題是我收到驗證錯誤消息后做錯了什么? BTW的完整代碼可以在github中找到 。
我自己解決問題-問題是AdminServlet.AddUser的回報。 因為我做了"redirect:/"
這導致創建包括BindingResult在內的全新對象,因此所有有關錯誤的信息都被刪除了。
變更后
@RequestMapping(value = "/AddUser", method = RequestMethod.POST)
public String AddUser(@ModelAttribute("user") @Valid User user, BindingResult result)
{
if (!result.hasErrors())
MainService.AddUser(user);
return "redirect:/";
}
至
@RequestMapping(value = "/AddUser", method = RequestMethod.POST)
public ModelAndView AddUser(@ModelAttribute("user") @Valid User user, BindingResult result)
{
ModelAndView mav = new ModelAndView();
mav.setViewName("index");
mav.addObject("ATMUsers", MainService.getAllUsers());
if (result.hasErrors())
mav.addObject("user", user);
else
{
mav.addObject("user", new User());
MainService.AddUser(user);
}
return mav;
}
一切都開始正常工作。
在MainService.AddUser(user);
周圍捕獲異常MainService.AddUser(user);
並在catch子句中將錯誤添加到BindingResult對象或重定向。
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