Struts 2 @VisitorFieldValidator验证全部表单而非指定表单的问题咨询

各位Struts2的老哥们，我最近在做Struts2的实验项目时碰到了一个关于@VisitorFieldValidator的困惑，想过来请教下大家的解决方案。

先说明下我的环境：使用Struts2 core + convention plugin 6.7.0，Action用的是默认拦截器栈。

下面是我的Action代码：

package name.matthewgreet.basicstrutsexperiments.experiment4.action;

import org.apache.struts2.ActionSupport;
import org.apache.struts2.convention.annotation.Action;
import org.apache.struts2.convention.annotation.Actions;
import org.apache.struts2.convention.annotation.InterceptorRef;
import org.apache.struts2.convention.annotation.Result;
import org.apache.struts2.convention.annotation.Results;
import org.apache.struts2.interceptor.validation.SkipValidation;
import com.opensymphony.xwork2.validator.annotations.VisitorFieldValidator;
import name.matthewgreet.basicstrutsexperiments.experiment4.form.ArithmeticForm;
import name.matthewgreet.basicstrutsexperiments.experiment4.form.DummyForm;

@InterceptorRef("defaultStack")
@Results({
    @Result(name=ActionSupport.ERROR, location="/pages/experiment4/Arithmetic.jsp"),
    @Result(name=ActionSupport.INPUT, location="/pages/experiment4/Arithmetic.jsp"),
    @Result(name=ActionSupport.SUCCESS, location="/pages/experiment4/Arithmetic.jsp")
})
public class ArithmeticAction extends ActionSupport {
    private static final long serialVersionUID = -6084392315736424463L;

    private ArithmeticForm form;
    private DummyForm dummyForm;
    private String resultText;

    @Actions({
        @Action("/experiment4/"),
        @Action("/experiment4/Arithmetic")
    })
    @Override
    @SkipValidation
    public String execute() throws Exception {
        try {
            int result;
            if (form == null) {
                resultText = "";
            } else if (form.getOperand2() != null) {
                switch (form.getOperator()) {
                    case "+":
                        result = form.getOperand1() + form.getOperand2();
                        break;
                    case "-":
                        result = form.getOperand1() - form.getOperand2();
                        break;
                    case "/":
                        result = form.getOperand1() / form.getOperand2();
                        break;
                    case "*":
                        result = form.getOperand1() + form.getOperand2();
                        break;
                    default:
                        result = 0;
                        break;
                }
                resultText = form.getOperand1() + " " + form.getOperator() + " " + form.getOperand2() + " = " + result;
            } else {
                resultText = "Operand 2 not set";
            }
            return SUCCESS;
        } catch (Exception e) {
            System.out.println("Action failed reason=" + e.getMessage());
            return ERROR;
        }
    }

    @Action("/Arithmetic_submit")
    public String submit() throws Exception {
        try {
            int result;
            if (form.getOperand2() != null) {
                switch (form.getOperator()) {
                    case "+":
                        result = form.getOperand1() + form.getOperand2();
                        break;
                    case "-":
                        result = form.getOperand1() - form.getOperand2();
                        break;
                    case "/":
                        result = form.getOperand1() / form.getOperand2();
                        break;
                    case "*":
                        result = form.getOperand1() + form.getOperand2();
                        break;
                    default:
                        result = 0;
                        break;
                }
                resultText = form.getOperand1() + " " + form.getOperator() + " " + form.getOperand2() + " = " + result;
            } else {
                resultText = "Operand 2 not set";
            }
            return SUCCESS;
        } catch (Exception e) {
            System.out.println("Action failed reason=" + e.getMessage());
            return ERROR;
        }
    }

    @VisitorFieldValidator(appendPrefix = true)
    public ArithmeticForm getForm() {
        if (form == null) {
            form = new ArithmeticForm();
        }
        return form;
    }

    @VisitorFieldValidator(appendPrefix = true)
    public DummyForm getDummyForm() {
        if (dummyForm == null) {
            dummyForm = new DummyForm();
        }
        return dummyForm;
    }

    public String getResultText() {
        return resultText;
    }
}

然后是我的ArithmeticForm代码：

package name.matthewgreet.basicstrutsexperiments.experiment4.form;

import java.io.Serializable;
import com.opensymphony.xwork2.validator.annotations.ConversionErrorFieldValidator;
import com.opensymphony.xwork2.validator.annotations.RequiredFieldValidator;
import com.opensymphony.xwork2.validator.annotations.RequiredStringValidator;

public class ArithmeticForm implements Serializable {
    private static final long serialVersionUID = -5287580238710655353L;

    private int operand1;
    private String operator;
    private Integer operand2;

    @ConversionErrorFieldValidator(message = "Operand 1 must be a number!", repopulateField = true, shortCircuit = true)
    @RequiredFieldValidator(message = "Operand 1 is required")
    public int getOperand1() {
        return operand1;
    }

    public void setOperand1(int operand1) {
        this.operand1 = operand1;
    }

    @RequiredStringValidator(message = "Operator is required")
    public String getOperator() {
        return operator;
    }

    public void setOperator(String operator) {
        this.operator = operator;
    }

    @ConversionErrorFieldValidator(message = "Operand 2 must be a number!", repopulateField = true, shortCircuit = true)
    @RequiredFieldValidator(message = "Operand 2 is required")
    public Integer getOperand2() {
        return operand2;
    }

    public void setOperand2(Integer operand2) {
        this.operand2 = operand2;
    }

    @Override
    public String toString() {
        return "ArithmeticForm [operand1=" + operand1 + ", operator=" + operator + ", operand2=" + operand2 + "]";
    }
}

（注：DummyForm是我加的一个测试用表单类，结构和ArithmeticForm类似，也给字段加了对应的验证注解）

现在说下我的问题：
我在Action里给ArithmeticForm和DummyForm的getter方法都加了@VisitorFieldValidator(appendPrefix = true)注解，本来是想让Struts2验证表单字段，但现在发现一个问题：当我提交ArithmeticForm的表单数据时，Struts2不仅会验证ArithmeticForm的字段，还会去验证DummyForm的字段——可DummyForm只是我用来测试的，这次请求根本没用到它，结果导致了不必要的验证错误。

我本来以为@VisitorFieldValidator只会验证当前请求关联的表单对象，或者可以配置只验证指定的表单，但现在看来只要加了这个注解的getter对应的表单都会被触发验证。

想请教下各位，有没有办法让Struts2只验证我指定的表单（比如这次请求里用到的ArithmeticForm），而不是所有带有@VisitorFieldValidator注解的表单呢？

内容来源于stack exchange