采取的是spring action 中的例子
驗證一個Student對象
???1.implements Validator接口(org.springframework.validation.Validator)
?????????public class StudentValidator implements Validator
?????????{
????????????public boolean supports(Class clazz)//必須實現的方法
????????????{return clazz.equals(Student.class)?;
??? ????????}
?????????? ?public void validate(Object command,Errors errors)
?????????? {
????????????? Student student =(Student)command;
????????????//?ValidationUtils.rejectIfEmpty? (Errors errors, String field, String errorCode, String defaultMessage)

???????????????ValidationUtils.rejectIfEmpty(errors,"login","required.login","login is required");
???????????????ValidationUtils.rejectIfEmpty(errors,"password","required.password","Password is required");
???????????????ValidationUtils.rejectIfEmpty(errors,"firstName","required.firstName","firstNameis required");
???????????????ValidationUtils.rejectIfEmpty(errors,"lastName","required.lastName","lastNameis required");
???????????????ValidationUtils.rejectIfEmpty(errors,"city","required.login","cityis required");
????????????????????????????????????????????validateEmail(student .email,errors);
???????????????validatePhone(student .phone,errors);
????????????}
????????????
????????????private static final String PHONE_REGXP="/(\\({0,1}(\\d{3})))/"
????????????private void validatePhone(String phone, Errors erros)
????????????{
?????????????ValidationUtils.rejectIfEmpty(errors,"phone","required.phone","phoneis required");
???????????? Perl5Util per5Util=new Perl5Util();
???????????? if(!per5Util.math(PHONE_REGXP,phone))
????????????{
??????????????errors.reject("invalid.phone","Phone number is invalid");
???????????????}
???????????????}????
??????????????private static final String Email_REGXP="/(\\({0,1}(\\d{3})))/"
????????????private void validateEmail(String phone, Errors erros)
????????????{
?????????????ValidationUtils.rejectIfEmpty(errors,"phone","required.phone","phoneis required");
???????????? Perl5Util per5Util=new Perl5Util();
???????????? if(!per5Util.math(Email_REGXP,email))
????????????{
??????????????errors.reject("invalid.phone","Phone number is invalid");
???????????????}
???????????????}?????????
?????

}
2.配置bean
??????<bean id="methodNameResolver"
class="org.springframework.web.servlet.mvc.multiaction.ParameterMethodNameResolver">
<property name="paramName"><value>method</value>
</property>
<property name="defaultMethodName"><value>view</value>
</property>
</bean>
<property name="validator"><bean class="com.StudentValidator "/>?
</property>
<property name="defaultMethodName"><value>view</value>
</property>
<bean name="/jsp/test.do" class="org.nightwalker.spaces.web.controller.TestController">
<property name="methodNameResolver">
<ref local="methodNameResolver"/>
</property>
</bean>

?

查看源代碼：
MultiActionController類：
??protected void bind(ServletRequest request, Object command) throws Exception {
??logger.debug("Binding request parameters onto MultiActionController command");
??ServletRequestDataBinder binder = createBinder(request, command);
??binder.bind(request);
??if (this.validators != null) {
???for (int i = 0; i < this.validators.length; i++) {
??????//首先調用supports
??? ??if (this.validators[i].supports(command.getClass())) {
?????ValidationUtils.invokeValidator(this.validators[i], command, binder.getErrors());
????}
???}
??}
??binder.closeNoCatch();
?}

類ValidationUtils：
public static void invokeValidator(Validator validator, Object obj, Errors errors) {
??if (validator != null) {
???if (logger.isDebugEnabled()) {
????logger.debug("Invoking validator [" + validator + "]");
???}
???if (obj != null && !validator.supports(obj.getClass())) {
????throw new IllegalArgumentException("Validator " + validator.getClass() +
??????" does not support " + obj.getClass());
???}
???validator.validate(obj, errors);
???if (logger.isDebugEnabled()) {
????if (errors.hasErrors()) {
?????logger.debug("Validator found " + errors.getErrorCount() + " errors");
????}
????else {
?????logger.debug("Validator found no errors");
????}
???}
??}
?}
?