Spring MVC中的验证组

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可以通过groups属性将Bean验证中的验证约束添加到一个或多个组。这使您可以限制在验证期间应用的约束集。在某些小组应先于其他小组进行验证（例如在向导中）的情况下，这可能很方便。从Spring MVC 3.1开始，可以通过org.springframework.validation.annotation.Validated注释使用验证组进行自动验证。在本文中，我将使用简单的Spring MVC应用程序来演示如何轻松使用验证组来验证Spring的MVC模型属性。

形成

让我们从将逐步验证的表单类开始。首先，我们定义代表约束组的接口：

public class Account implements PasswordAware {interface ValidationStepOne {// validation group marker interface}interface ValidationStepTwo {// validation group marker interface}
}

验证约束

接下来，我们将约束分配给组。请记住，如果您不提供组，则将使用默认组。另请注意@SamePasswords和@StrongPassword –自定义约束，必须定义groups属性：

@SamePasswords(groups = {Account.ValidationStepTwo.class})
public class Account implements PasswordAware {@NotBlank(groups = {ValidationStepOne.class})private String username;@Email(groups = {ValidationStepOne.class})@NotBlank(groups = {ValidationStepOne.class})private String email;@NotBlank(groups = {ValidationStepTwo.class})@StrongPassword(groups = {ValidationStepTwo.class})private String password;@NotBlank(groups = {ValidationStepTwo.class})private String confirmedPassword;// getters and setters
}

巫师

有了Account ，我们可以创建一个三步向导@Controller ，该向导将允许用户创建一个帐户。第一步，我们将让Spring验证ValidationStepOne组中的约束：

@Controller
@RequestMapping("validationgroups")
@SessionAttributes("account")
public class AccountController {@RequestMapping(value = "stepOne")public String stepOne(Model model) {model.addAttribute("account", new Account());return VIEW_STEP_ONE;}@RequestMapping(value = "stepOne", method = RequestMethod.POST)public String stepOne(@Validated(Account.ValidationStepOne.class) Account account, Errors errors) {if (errors.hasErrors()) {return VIEW_STEP_ONE;}return "redirect:stepTwo";}
}

为了触发组的验证，我使用了@Validated注解。该批注采用带有组类型的var-arg参数。代码@Validated(ValidationStepOne.class)触发ValidationStepOne组中约束的ValidationStepOne 。

在下一步中，我们将让Spring在ValidationStepTwo组中验证约束：

@Controller
@RequestMapping("validationgroups")
@SessionAttributes("account")
public class AccountController {@RequestMapping(value = "stepTwo")public String stepTwo() {return VIEW_STEP_TWO;}@RequestMapping(value = "stepTwo", method = RequestMethod.POST)public String stepTwo(@Validated(Account.ValidationStepTwo.class) Account account, Errors errors) {if (errors.hasErrors()) {return VIEW_STEP_TWO;}return "redirect:summary";}
}

在摘要步骤中，我们将确认输入的数据，并让Spring验证两组的约束：

@Controller
@RequestMapping("validationgroups")
@SessionAttributes("account")
public class AccountController {@RequestMapping(value = "summary")public String summary() {return VIEW_SUMMARY;}@RequestMapping(value = "confirm")public String confirm(@Validated({Account.ValidationStepOne.class, Account.ValidationStepTwo.class}) Account account, Errors errors, SessionStatus status) {status.setComplete();if (errors.hasErrors()) {// did not pass full validation}return "redirect:start";}
}

在Spring 3.1之前，您可以手动触发验证。我在以前的一篇文章中对此进行了描述： http : //blog.codeleak.pl/2011/03/how-to-jsr303-validation-groups-in.html

注意：如果要在不使用Spring的情况下使用验证组，则需要将组传递给javax.validation.Validator#validate() ：

没有Spring的验证组

Validator validator = Validation.buildDefaultValidatorFactory().getValidator();
Account account = new Account();// validate with first group
Set<ConstraintViolation<Account>> constraintViolations =validator.validate(account, Account.ValidationStepOne.class);
assertThat(constraintViolations).hasSize(2);// validate with both groups
Set<ConstraintViolation<Account>> constraintViolations =validator.validate(account, Account.ValidationStepOne.class, Account.ValidationStepTwo.class);
assertThat(constraintViolations).hasSize(4);

这也是测试验证的最简单方法：

public class AccountValidationTest {private Validator validator = Validation.buildDefaultValidatorFactory().getValidator();@Testpublic void shouldHaveFourConstraintViolationsWhileValidatingBothGroups() {Account account = new Account();Set<ConstraintViolation<Account>> constraintViolations = validator.validate(account, Account.ValidationStepOne.class, Account.ValidationStepTwo.class);assertThat(constraintViolations).hasSize(4);}@Testpublic void shouldHaveTwoConstraintViolationsWhileStepOne() {Account account = new Account();Set<ConstraintViolation<Account>> constraintViolations = validator.validate(account, Account.ValidationStepOne.class);assertThat(constraintViolations).hasSize(2);}
}