struts中自定义validator验证

struts中自定义validator验证

很多时候需要验证“密码”与“重复密码”是否一致，如果放在服务器端验证就浪费资源了。
如何在客户端进行验证呢？JS可以实现，但是struts的validator框架是否能实现呢？
跟着我一起做一个例子吧。
代码见：http://download.csdn.net/user/qing2005

在原有的验证框架内容上进行改善
1. 新增MyFieldChecks.java类
-----------------------------------------------------------------------------------------------
package common;

import java.io.*;
import org.apache.struts.validator.Resources;
import org.apache.commons.validator.GenericValidator;
import org.apache.commons.validator.ValidatorUtil;
import javax.servlet.http.HttpServletRequest;
import org.apache.commons.validator.Field;
import org.apache.commons.validator.ValidatorAction;
import org.apache.struts.action.ActionErrors;
import org.apache.commons.validator.Arg;

public class MyFieldChecks implements Serializable {
 public static boolean validateCompare(Object bean,
             ValidatorAction va, Field field,
             ActionErrors errors,
             HttpServletRequest request) {

  String value = null;
  if (isString(bean)) {
   value = (String) bean;
  } else {
   value = ValidatorUtil.getValueAsString(bean, field.getProperty());
  }

  if (!GenericValidator.isBlankOrNull(value)) {
   Arg arg=field.getArg1();
   String arg1Key=field.getVarValue("compareControl");
   String strCompare=ValidatorUtil.getValueAsString(bean,arg1Key);
   if(strCompare==null || !value.equals(strCompare)){
    errors.add(field.getKey(), Resources.getActionError(request, va, field));
    return false;
   }
  }
  return true;
 }
 
 /**
  *  Return <code>true</code> if the specified object is a String or a <code>null</code>
  *  value.
  *
  * @param o Object to be tested
  * @return The string value
  */
 protected static boolean isString(Object o) {
  return (o == null) ? true : String.class.isInstance(o);
 }
}
==========================================================================

2. 在validator-rules.xml最后新增片段
-----------------------------------------------------------------------------------------------
  <validator name="compare" classname="common.MyFieldChecks" method="validateCompare" methodParams="java.lang.Object,
                       org.apache.commons.validator.ValidatorAction,
                       org.apache.commons.validator.Field,
                       org.apache.struts.action.ActionErrors,
                       javax.servlet.http.HttpServletRequest" depends="required" msg="errors_compare">
   <javascript>
    <![CDATA[ function validateCompare(form) {
                var isValid = true;
                var focusField = null;
                var i = 0;
                var fields = new Array();
                oRange = new compare();
                for (x in oRange) {
                    var field = form[oRange[x][0]];

                    if ((field.type == 'text' ||
                         field.type == 'textarea' ||
       field.type=='password') &&
                        (field.value.length > 0)) {
                       
                        var iCompareControl = oRange[x][2]("compareControl");
      
      var iValue=document.getElementsByName("iCompareControl").value;

      if(field.value!=iValue){
          if (i == 0) {
         focusField = field;
       }
       fields[i++] = oRange[x][1];
       isValid = false;
      }
                    }
                }
                if (fields.length > 0) {
                    focusField.focus();
                    alert(fields.join('/n'));
                }
                return isValid;
            }]]>
   </javascript>
  </validator>
==========================================================================
注意：classname是common.MyFieldChecks

3.在validation.xml中添加一个compare验证
-----------------------------------------------------------------------------------------------
   <field property="reply" depends="compare">
       <arg0 key="register_password"/>
    <arg1 key="${var:compareControl}" resource="false"/>
    <var>
        <var-name>compareControl</var-name>
     <var-value>password</var-value>
    </var>
   </field>
==========================================================================
注意：一定要定义compareControl，这和JS等都有关

4. 在JSP页面中使用验证
-----------------------------------------------------------------------------------------------
1）先测试不用JS方式
<html:messages id="error">
    <li><bean:write name="error"/></li>
</html:messages>
</ul>
</logic:messagesPresent>
<html:form action="/registerAction.do" method="post" >
......
结果：验证成功！

2）测试JS方式
<html:messages id="error">
    <li><bean:write name="error"/></li>
</html:messages>
</ul>
</logic:messagesPresent>
<html:form action="/registerAction.do" method="post" onsubmit="return validateRegisterForm(this)">
......
</html:form>
<html:javascript formName="registerForm"/>
结果：验证成功！
==========================================================================

总结：
1）环境：Winxp+JBuilder2006+Tomcat5.5+JDK1.5

2)  一开始怎么都不成功，跟踪调试后发现common.MyFieldChecks空指针异常，
百思不得其解，最后发现在“项目/RegisterModule/WEB-INF/classes/common”下没有MyFieldChecks类，
于是我把“项目/classes/common”下的MyFieldChecks类拷贝到上述目录，结果就可以了。
为了不让初学者绕圈子，请注意这点，并且，如果更改了MyFieldChecks类，也需要做上述复制。切记！

3）写JS验证时调试了很久，一方面不是很熟这种写法，另一方面每次调试都非常不方便，
后来干脆调试生成的HTML文本，调试通过后再写到validator-rules.xml中。

4）翻了很多资料、很多文章，写完整的实在太少，我想象我这样的初学者一定很多，
一次次的打击不仅仅是程序运行的失败，更是信心的考验。希望这篇文章能给你有所帮助！