大家好，每当我试图在我的 Spring 调用验证器时，我都会收到以下错误

Servlet.service() for servlet spring threw exception: java.lang.IllegalStateException: Invalid target for Validator 

@Controller 
public class NewUserRegistration  
{ 
    @Autowired 
    private UserService userService;     
 
    @Autowired 
    private NewUserValidator newUserValidator; 
 
    @InitBinder 
    public void initBinder(WebDataBinder binder) 
    { 
       binder.setValidator(newUserValidator); 
    } 
 
    @RequestMapping(value="/newUserAdd", method=RequestMethod.POST) 
    public String addUser(@ModelAttribute("user")@Valid User user,BindingResult result, Model model) 
    { 
          return "NewUser"; 
    } 

@Component 
public class NewUserValidator  implements Validator 
{ 
    @Override 
    public boolean supports(Class<?> classz)  
    { 
        return NewUserRegistration.class.equals(classz); 
    } 
 
    @Override 
    public void validate(Object obj, Errors error)  
    { 
    //Validation login for fields 
    } 
} 

<form:form action="newUserAdd" method="POST" modelAttribute="user"> 
        <center> 
        <table> 
            <tr><td>User Id:</td><td><input name="userId" type="text" /></td><td><font color="red"><c:out value="${userIdError}" /></font> </td></tr> 
            <tr><td>Password:</td><td><input name="userPassword" type="password"/></td><td><font color="red"><c:out value="${userPasswordError}" /></font></td></tr> 
            <tr><td>Confirm Password:</td><td><input name="userConfirmPassword" type="password"/></td><td><font color="red"><c:out value="${userPasswordError}" /></font></td></tr> 
            <tr><td>Name:</td><td><input name="userName" type="text"/></td><td><font color="red"><c:out value="${userPasswordError}" /></font></td></tr> 
            <tr><td></td><td><input type="submit" value="Create"/></td></tr> 
 
        </table> 
        </center> 
    </form:form> 

请您参考如下方法:

问题实际上是在 Validator 类中，您使用的是 NewUserRegistration 的对象，这是错误的，因为您想验证 User 的对象而不是 NewUserRegistration 的对象。

@Override 
    public boolean supports(Class<?> classz)  
    { 
        return NewUserRegistration.class.equals(classz); 
    } 

@Override 
    public boolean supports(Class<?> classz)  
    { 
        return User.class.equals(classz); 
    }