如果你使用过struts先前的版本，你就会注意到你需要花费大量的时候来写ActionForm类文件，而这些类文件
对于struts都是非常关键的（它充当“View”的一部分），通常它的结构就是bean properties在加上一个
validate方法（有时还有reset方法）。 随着struts1.1版本的推出，开发员有了另外一种方法来完成前面的任务：使用DynaBeans。DynaBeans动态生
成Java Beans。这就意味着我们可以通过配置（通常利用xml） 来生成formbean而不是在formbean中硬编码。 为了了解DynaBeans（struts中为Dynaforms）是如何工做的，让我们看一个简单的表单，字段有：name，
address，telephone等，下面的代码为通常的写法（没有使用Dynaforms）。 article1.CustomerForm package article1; import org.apache.struts.action.ActionForm; import org.apache.struts.action.ActionErrors; import org.apache.struts.action.ActionMapping; import org.apache.struts.action.ActionError; import javax.servlet.http.HttpServletRequest; public class CustomerForm extends ActionForm { protected boolean nullOrBlank (String str) { return ((str == null) || (str.length() == 0)); } public ActionErrors validate(ActionMapping mapping, HttpServletRequest request) { ActionErrors errors = new ActionErrors(); if (nullOrBlank(lastName)) { errors.add("lastName", new ActionError("article1.lastName.missing")); } if (nullOrBlank(firstName)) { errors.add("firstName", new ActionError("article1.firstName.missing")); } if (nullOrBlank(street)) { errors.add("street", new ActionError("article1.street.missing")); } if (nullOrBlank(city)) { errors.add("city", new ActionError("article1.city.missing")); } if (nullOrBlank(state)) { errors.add("state", new ActionError("article1.state.missing")); } if (nullOrBlank(postalCode)) { errors.add("postalCode", new ActionError("article1.postalCode.missing")); } if (nullOrBlank(phone)) { errors.add("phone", new ActionError("article1.phone.missing")); } return errors; } private String lastName; private String firstName; private String street; private String city; private String state; private String postalCode; private String phone; public String getLastName() { return lastName; } public void setLastName(String lastName) { this.lastName = lastName; } public String getFirstName() { return firstName; } public void setFirstName(String firstName) { this.firstName = firstName; } public String getStreet() { return street; } public void setStreet(String street) { this.street = street; } public String getCity() { return city; } public void setCity(String city) { this.city = city; } public String getState() { return state; } public void setState(String state) { this.state = state; } public String getPostalCode() { return postalCode; } public void setPostalCode(String postalCode) { this.postalCode = postalCode; } public String getPhone() { return phone; } public void setPhone(String phone) { this.phone = phone; } } 看到上边的写法（这么长一段代码[虽然大多的工具都可以自动生成set和get方法]感想如何？如果要为每一个表
单配备一个formbean，那么将是一件多了令人痛苦的事情??译者注），你知道了它是一个标准的JavaBean，只
是多了一个validate方法，validate方法确保client断的输入都是合法的。 相应的jsp页面同样也是很简单的，如下： customer.jsp <%@ taglib uri="/WEB-INF/c.tld" prefix="c" %> <%@ taglib prefix="fmt" uri="/WEB-INF/fmt.tld" %> <%@ taglib uri="/WEB-INF/struts-tiles.tld" prefix="tiles" %> <%@ taglib uri="/WEB-INF/struts-html.tld" prefix="html" %> <head> <title>Example of a standard Customer form</title> </head> <h1>Example of a standard Customer form</h1> <html:form action="/addCustomer"> Last Name: <html:text property="lastName"/> <html:errors property="lastName" /><br> First Name: <html:text property="firstName"/> <html:errors property="firstName" /><br> Street Addr: <html:text property="street"/> <html:errors property="street" /><br> City: <html:text property="city"/> <html:errors property="city" /><br> State: <html:text property="state" maxlength="2" size="2" /> <html:errors property="state" /><br> Postal Code: <html:text property="postalCode" maxlength="5" size="5" /> <html:errors property="postalCode" /><br> Telephone: <html:text property="phone" maxlength="11" size="11" /> <html:errors property="phone" /><br> <html:submit/> </html:form> 相应的action也没有复杂的业务代码，只是将从client端传过来的值打印到控制台。 article1.AddCustomerAction package article1; import org.apache.struts.action.Action; import org.apache.struts.action.ActionMapping; import org.apache.struts.action.ActionForward; import org.apache.struts.action.ActionForm; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.ServletException; import java.io.IOException; public class AddCustomerAction extends Action { public ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{ CustomerForm custForm = (CustomerForm) form; System.out.println("lastName = " + custForm.getLastName()); System.out.println("firstName = " + custForm.getFirstName()); System.out.println("street = " + custForm.getStreet()); System.out.println("city = " + custForm.getCity()); System.out.println("state = " + custForm.getState()); System.out.println("postalCode = " + custForm.getPostalCode()); System.out.println("phone = " + custForm.getPhone()); return mapping.findForward("success"); } } 下面看看struts-config.xml的配置，struts利用该配置文件将上述文件联系到一起来协同完成任务。 <struts-config> <form-beans> <form-bean name="customerForm" type="jdj.article1.Customer" /> </form-beans> <action-mappings> <action path="/addCustomer" type="article1.AddCustomerAction" name="customerForm" scope="request" input="/addCustomer.jsp"> <forward name="success" path="/addCustomerSucceeded.jsp" redirect="false" /> </action> </action-mappings> <message-resources parameter="ApplicationResources" /> <plug-in className="org.apache.struts.validator.ValidatorPlugIn"> <set-property value="/WEB-INF/validator-rules.xml" property="pathnames" /> struts-config.xml</plug-in></struts-config> <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE struts-config PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 1.1//EN" "http://jakarta.apache.org/struts/dtds/struts-config_1_1.dtd"> <struts-config> <form-beans> <form-bean name="customerForm" type="article1.CustomerForm" /> </form-beans> <action-mappings> <action path="/addCustomer" type="article1.AddCustomerAction" name="customerForm" scope="request" input="/customer.jsp"> <forward name="success" path="/addCustomerSucceeded.jsp" redirect="false" /> </action> </action-mappings> <message-resources parameter="ApplicationResources" /> <plug-in className="org.apache.struts.validator.ValidatorPlugIn"> <set-property value="/WEB-INF/validator-rules.xml" property="pathnames" /> </plug-in> </struts-config> 上边通过配置，customerForm来引用CustemerForm类， “/addCustomer”action使用customerForm并
且触发article1.AddCustomerAction来处理请求。 到现在为止，上边代码熟悉struts得都应该很熟悉但是，如果应用struts1.1的新特性，你将会用更少的代码
来完成上述同样的功能。使用Dynaforms,我们应该更改customerForm在struts-config.xml中信息来使用
org.apache.struts.action.DynaActionForm （为了便于读者比较使用前后的差别，我们将使用新的类新
的jsp页面来完成同样的功能） 使用DynaActionForm，你可以利用form-property xml标签，它允许你在struts-config.xml中定义
formbean的属性元素。以我们的例子来说，struts-config.xml中将是如下这个样子： <form-bean name="dynaCustomerForm" type="org.apache.struts.action.DynaActionForm"> <form-property name="lastName" type="java.lang.String"/> <form-property name="firstName" type="java.lang.String"/> <form-property type="java.lang.String" name="street"/> <form-property name="city" type="java.lang.String"/> <form-property name="state" type="java.lang.String"/> <form-property name="postalCode" type="java.lang.String"/> </form-bean> 上边的改动对于jsp页面没有任何的影响。不过你要对于原来的action进行稍微的改动应为：你现在已经不在向
execute()中传递formbean（没有get set方法），所以 你应该把form转型到DynaActionForm，然后利用
方法get(filename)来取得client端数据新的action代码如下： article1.AddDynaCustomerAction package article1; import org.apache.struts.action.*; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.ServletException; import java.io.IOException; public class AddDynaCustomerAction extends Action { public ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{ DynaActionForm custForm = (DynaActionForm) form; System.out.println("lastName = " + custForm.get("lastName")); System.out.println("firstName = " + custForm.get("firstName")); System.out.println("street = " + custForm.get("street")); System.out.println("city = " + custForm.get("city")); System.out.println("state = " + custForm.get("state")); System.out.println("postalCode = " + custForm.get("postalCode")); System.out.println("phone = " + custForm.get("phone")); return mapping.findForward("success"); } } 从上边的代码可以看出，似乎”屏蔽“了actionform，然而我们也“丢失”了一些其他的，譬如：严整输入合
法性的问题。有两种方法可以恢复校验功能：一是创建一个DynaActionForm的子类，然后在子类中实现
validate()方法。如下代码： article1.DynaCustomerForm package article1; import org.apache.struts.action.*; import javax.servlet.http.HttpServletRequest; public class DynaCustomerForm extends DynaActionForm { protected boolean nullOrBlank (String str) { return ((str == null) || (str.length() == 0)); } public ActionErrors validate(ActionMapping mapping, HttpServletRequest request) { ActionErrors errors = new ActionErrors(); if (nullOrBlank((String)this.get("lastName"))) { errors.add("lastName", new ActionError("article1.lastName.missing")); } if (nullOrBlank((String)this.get("firstName"))) { errors.add("firstName", new ActionError("article1.firstName.missing")); } if (nullOrBlank((String)this.get("street"))) { errors.add("street", new ActionError("article1.street.missing")); } if (nullOrBlank((String)this.get("city"))) { errors.add("city", new ActionError("article1.city.missing")); } if (nullOrBlank((String)this.get("state"))) { errors.add("state", new ActionError("article1.state.missing")); } if (nullOrBlank((String)this.get("postalCode"))) { errors.add("postalCode", new ActionError("article1.postalCode.missing")); } if (nullOrBlank((String)this.get("phone"))) { errors.add("phone", new ActionError("article1.phone.missing")); } return errors; } } 如果是这样，我们就要更改struts-config.xml来使用DynaActionForm的子类，这样的效果似乎是又回到了
先前的样子（为每一个表单写DynaActionForm
），
