ここまでのまとめ。

Struts Validator

最終的なソース
LoginForm.java(WEB-INF/classes)

import org.apache.struts.validator.ValidatorForm;

public class LoginForm extends ValidatorForm {
  private String userID;
  private String password;
  
  public String getPassword() {
    return password;
  }

  public void setPassword(String password) {
    this.password = password;
  }

  public String getUserID() {
    return userID;
  }

  public void setUserID(String userID) {
    this.userID = userID;
  }
}

Login.jsp(/)

<%@page contentType="text/html; charset=Windows-31J"%>
<%@taglib uri="/tags/struts-html" prefix="html"%>

<html:html>
<head>
<meta HTTP-EQUIV="Content-Type" CONTENT="text/html;charset=Windows-31J">
<meta HTTP-EQUIV="Content-Language" CONTENT="ja">
<meta http-equiv="Pragma" content="no-cache">
<meta http-equiv="Cache-Control" content="no-cache">
</head>
<body>
<html:errors/>
<html:form action="/Login">
名前:<html:text property="userID"/><br>
パスワード:<html:text property="password"/><br>
<html:submit property="submit" value="ログイン"/>
</html:form>
</body>
</html:html>

struts-config.xml(WEB-INF)

<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE struts-config PUBLIC
          "-//Apache Software Foundation//DTD Struts Configuration 1.2//EN"
          "http://struts.apache.org/dtds/struts-config_1_2.dtd">
<struts-config>
  <data-sources />
  <form-beans>
      <form-bean name="loginForm" type="LoginForm" />
  </form-beans>
  <global-exceptions />
  <global-forwards />
  <action-mappings>
      <action path="/Login" type="LoginAction" name="loginForm" scope="request" input="/Login.jsp" validate="true">
          <forward name="next" path="/loginSuccess.jsp"/>
          <forward name="reject" path="/rejectUser.jsp"/>
      </action>
  </action-mappings>
  <message-resources parameter="MessageResources" />
  <plug-in className="org.apache.struts.validator.ValidatorPlugIn">
    <set-property property="pathnames" value="/WEB-INF/validator-rules.xml,/WEB-INF/validation.xml" />
    <set-property property="stopOnFirstError" value="true" />
  </plug-in>
</struts-config>

validation.xml(WEB-INF)

<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE form-validation PUBLIC
          "-//Apache Software Foundation//DTD Commons Validator Rules Configuration 1.1.3//EN"
          "http://jakarta.apache.org/commons/dtds/validator_1_1_3.dtd">
<form-validation>
  <formset>
    <form name="loginForm">
      <field property="userID" depends="required,maxlength">
        <arg0 key="loginForm.userID"/>
        <arg1 name="maxlength" key="${var:maxlength}" resource="false" />
        <var>
          <var-name>maxlength</var-name>
          <var-value>5</var-value>
        </var>
      </field>
      <field property="password" depends="required,maxlength">
        <arg0 key="loginForm.password"/>
        <arg1 name="maxlength" key="${var:maxlength}" resource="false" />
        <var>
          <var-name>maxlength</var-name>
          <var-value>5</var-value>
        </var>
      </field>
    </form>
  </formset>
</form-validation>

MessageResources.properties(WEB-INF/classes)

errors.required={0} is required.
errors.minlength={0} can not be less than {1} characters.
errors.maxlength={0} can not be greater than {1} characters.
errors.invalid={0} is invalid.

loginForm.userID=User ID
loginForm.password=Password

MessageResources_ja.properties(WEB-INF/classes)

errors.required={0} \u3092\u5165\u529b\u3057\u3066\u304f\u3060\u3055\u3044\u3002
errors.minlength={0} \u306f {1} \u6587\u5b57\u4ee5\u4e0a\u3067\u306a\u3051\u308c\u3070\u3044\u3051\u307e\u305b\u3093
errors.maxlength={0} \u306f {1} \u6587\u5b57\u4ee5\u4e0b\u3067\u306a\u3051\u308c\u3070\u306a\u308a\u307e\u305b\u3093\u3002
errors.invalid={0} \u306f\u6b63\u3057\u304f\u3042\u308a\u307e\u305b\u3093\u3002
errors.range={0} \u306f {1} \u304b\u3089 {2} \u306e\u9593\u3067\u306a\u3051\u308c\u3070\u306a\u308a\u307e\u305b\u3093\u3002

loginForm.userID=\u30e6\u30fc\u30b6\u30fcID
loginForm.password=\u30d1\u30b9\u30ef\u30fc\u30c9

validator-rules.xml(WEB-INF)
commons-validator.jar(WEB-INF/lib)

細かい設定とかは Struts のマニュアルでも、google 先生にでも問い合わせてみりゃ。
これでサーバーサイド検証機能はＯＫ。

次はクライアントサイト検証(Javascript)と Dynaform / DynaValidatorForm のあたりかなー
しかし、そろそろ Eclipse でも導入しないとしんどい感じになってきた。Struts の内部へステップインすればログ読みながら１歩１歩って感じじゃ無い駆け足での進化が可能な筈やから。

どうすっかなー