使用其它类型的命令控制器，命令对象（POJO JavaBean）只装载一次，使用向导控制器，用户没完成向导页面中的一步，都会有一个命令对象装载。使用向导，我们只做一次验证是不可行的，因为如果你检查的太早的话，找到的验证问题可能是由于用户没有完成向导而导致的，相反，在完成按钮按下后检查就太迟了，因为发现的问题可能跨越了多了页面，我们应该回退到哪个页面呢？
根据 http://blog.csdn.net/daryl715/archive/2007/06/11/1647870.aspx这篇心得的实现，我们进行修改，加入验证功能
首先编写JavaBean Vote的验证单元
package model;import org.springframework.validation.Errors;import org.springframework.validation.Validator;
public class FeedBackValidator implements Validator ...{
public boolean supports(Class cls) ...{ return cls.equals(Vote.class);
} public void validate(Object object, Errors errors) ...{ } public void validateName(String name,Errors errors)...{ if(name==null||name.equals(""))...{ errors.rejectValue("name", "not null",null, "name必须输入"); } } public void validateOption(String option,Errors errors)...{ if(option==null||option.equals(""))...{ errors.rejectValue("option", "not null",null, "option必须输入"); } } public void validateResult(String result,Errors errors)...{ if(result==null||result.equals(""))...{ errors.rejectValue("result", "not null",null, "result必须输入"); } } public void validateId(String id,Errors errors)...{ if(id==null||id.equals(""))...{ errors.rejectValue("id", "not null",null, "id必须输入"); } }
}
修改train-servlet.xml,注入validator
<bean id="FeedbackController" class="Action.FeedBackWizardController"> <property name="successView"><value>formWizard/thankyou</value> </property> <property name="cancelView"><value>formWizard/first</value> </property> <property name="commandClass"><value>model.Vote</value></property> <property name="validator"> <bean class="model.FeedBackValidator"/> </property> <property name="pages"> <list> <value>formWizard/first</value> <value>formWizard/id</value> <value>formWizard/name</value> <value>formWizard/option</value> <value>formWizard/result</value> </list> </property></bean>
修改页面，以id.jsp为例
<body>
<spring:bind path="command.id">
<form action="feedback.mvc" method="post">
id: <input type="text" name="id" value="<c:out value="${status.value}"/>"/>
<c:if test="${status.error}">
<font color="#FF0000">
错误:
<c:forEach items="${status.errorMessages}" var="error">
<c:out value="${error}"/>
</c:forEach>
</font>
</c:if>
<input type="submit" value="下一步" name="_target2" />
<input type="submit" value="取消" name="_cancel"/>
<input type="submit" value="完成" name="_finish"/>
</form>
</spring:bind>
</body>
其他页面和id.jsp类似
控制器：新覆盖了validatePage方法，实现验证功能
package Action;import java.util.Enumeration;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import model.FeedBackValidator;import model.Vote;import org.springframework.validation.BindException;import org.springframework.validation.Errors;import org.springframework.web.servlet.ModelAndView;import org.springframework.web.servlet.mvc.AbstractWizardFormController;import org.springframework.web.util.WebUtils;public class FeedBackWizardController extends AbstractWizardFormController ...{ private String successView; private String cancelView; protected void validatePage(Object object, Errors errors, int page,boolean isFinish) ...{ Vote vote=(Vote)object; FeedBackValidator feedBackValidator=(FeedBackValidator)getValidator(); if(page==1)...{//检查第一页的id feedBackValidator.validateId(vote.getId(), errors); } if(page==2)...{//检查第二页的name feedBackValidator.validateName(vote.getName(), errors); } if(page==3)...{//检查第三页的option feedBackValidator.validateOption(vote.getOption(), errors); } if(page==4)...{//检查第四页的result feedBackValidator.validateResult(vote.getResult(), errors); } if(isFinish)...{ //表单向导结束 System.out.println("form finished"); } } public String getCancelView() ...{ return cancelView; } public void setCancelView(String cancelView) ...{ this.cancelView = cancelView; } public String getSuccessView() ...{ return successView; } public void setSuccessView(String successView) ...{ this.successView = successView; } protected ModelAndView processCancel(HttpServletRequest request, HttpServletResponse response, Object object, BindException exception) throws Exception ...{ return new ModelAndView(this.getCancelView()); } protected ModelAndView processFinish(HttpServletRequest request, HttpServletResponse response, Object object, BindException exception) throws Exception ...{ Vote vote=(Vote)object; return new ModelAndView(this.getSuccessView(),"vote",vote); }}