DispatchAction类

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DispatchAction类

DispatchAction类是为了执行聚合操作而设计的Action类。用HTML标签和<html:html>标签都可以实现，但是要写js脚本代码。（用<html:html>实现时，要设置<html:form method=”post”>）使用请求参数值确定调用哪种方法。Struts-config.xml中配置如下：

DispatchAction类使用

Html方式：

1 编写脚本文件:

function doSubmit(operate)

{

document.forms[0].elements["operate"].value=operate;

document.forms[0].submit();

}

2 设置隐藏域，用于传值。

3 struts.config.xml中的parameter="operate"要与<input type="hidden" name="operate">中的name属性一致。

<html:html>

前三步都相同，但要设置<html:form>为method=”post” <action

attribute="calcForm"

name="calcForm"

path="/calc"

scope="request"

type="cn.action.CalcAction"

parameter="operate">

</action>

属性

描述

Path

Action类的相对路径

Name

与本操作关联的Action bean的名称

Type

连接到本映射的Action类的全称（可有包名）

Scope

ActionForm bean的作用域（请求或会话）

Prefix

用来匹配请求参数与bean属性的前缀

Suffix

用来匹配请求参数与bean属性的后缀

attribute

作用域名称。

className

ActionMapping对象的类的完全限定名默认的类是org.apache.struts.action.ActionMapping

input

输入表单的路径，指向bean发生输入错误必须返回的控制

unknown

设为true，操作将被作为所有没有定义的ActionMapping的URI的默认操作

validate

设置为true，则在调用Action对象上的perform()方法前，ActionServlet将调用ActionForm bean的validate()方法来进行输入检查

parameter

指定请求中方法名称参数对应的参数名称。

在编写DispatchAction的代码时，不仅指明映射路径，还要附加一个method的参数，指用调用的方法名称。

<form>中的method属性也要设为post方式。

如：http://localhost:8080/action/calc.do?operate=doAdd

例子：用html标签实现的四则运算,不带验证！

Input.jsp代码如下：

<%@ page language="java" pageEncoding="gb18030"%>

<html>

<head>

<title>DispatchAction</title>

function doSubmit(operate)

{

document.forms[0].elements["operate"].value=operate;

document.forms[0].submit();

}

</script>

</head>

<body>

第一个数 : <input type="text" name="num1"/><br/>

第二个数 : <input type="text" name="num2"/><br/>

<input type="hidden" name="operate">//主要是用隐藏域来实现

</form>

</body>

</html>

CalcAction.java代码如下：

package cn.action;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

import org.apache.struts.action.ActionForm;

import org.apache.struts.action.ActionForward;

import org.apache.struts.action.ActionMapping;

import org.apache.struts.actions.DispatchAction;

import cn.form.CalcForm;

import org.apache.struts.action.ActionMessages;

import org.apache.struts.action.ActionMessage;

publicclass CalcAction extends DispatchAction {

privateintnum1=0;

privateintnum2=0;

//加

public ActionForward doAdd(ActionMapping mapping, ActionForm form,

HttpServletRequest request, HttpServletResponse response) {

CalcForm calcForm = (CalcForm) form;// TODO Auto-generated method stub

//ActionMessages errors=new ActionMessages();

HttpSession session=request.getSession();

session=request.getSession();

num1=Integer.parseInt(calcForm.getNum1());

num2=Integer.parseInt(calcForm.getNum2());

session.setAttribute("result", Integer.valueOf((num1+num2)));

return mapping.findForward("result");

}

//减

public ActionForward doSubtract(ActionMapping mapping, ActionForm form,

HttpServletRequest request, HttpServletResponse response) {

CalcForm calcForm = (CalcForm) form;// TODO Auto-generated method stub

HttpSession session=request.getSession();

session=request.getSession();

num1=Integer.parseInt(calcForm.getNum1());

num2=Integer.parseInt(calcForm.getNum2());

session.setAttribute("result", Integer.valueOf((num1-num2)));

return mapping.findForward("result");

}

//乘

public ActionForward doMultiply(ActionMapping mapping, ActionForm form,

HttpServletRequest request, HttpServletResponse response) {

CalcForm calcForm = (CalcForm) form;// TODO Auto-generated method stub

HttpSession session=request.getSession();

session=request.getSession();

num1=Integer.parseInt(calcForm.getNum1());

num2=Integer.parseInt(calcForm.getNum2());

session.setAttribute("result", Integer.valueOf((num1*num2)));

return mapping.findForward("result");

}

//除

public ActionForward doDivide(ActionMapping mapping, ActionForm form,

HttpServletRequest request, HttpServletResponse response) {

CalcForm calcForm = (CalcForm) form;// TODO Auto-generated method stub

ActionMessages errors=calcForm.validate(mapping, request);

if(Integer.parseInt(calcForm.getNum2())==0){

errors.add("error2", new ActionMessage("errors.validate.zero"));

super.saveErrors(request, errors);//调用ActionForm方法保存这个错误信息

return mapping.findForward("input");

}

HttpSession session=request.getSession();

session=request.getSession();

num1=Integer.parseInt(calcForm.getNum1());

num2=Integer.parseInt(calcForm.getNum2());

session.setAttribute("result", Integer.valueOf((num1/num2)));

return mapping.findForward("result");

}

Struct-config.xml配置如下：

<action-mappings >

<action

attribute="calcForm"

name="calcForm"

path="/calc"

scope="request"

type="cn.action.CalcAction"

parameter="operate">

</action>

</action-mappings>

例子：用<html:html>标签实现的四则运算，带验证！

Input.jsp页面代码如下：

<%@ page language="java" pageEncoding="gb18030"%>

<%@ taglib uri="http://jakarta.apache.org/struts/tags-bean" prefix="bean"%>

<%@ taglib uri="http://jakarta.apache.org/struts/tags-html" prefix="html"%>

<html:html>

<head>

<title>DispatchAction2</title>

function doSubmit(operate)

{

document.forms[0].elements["operate"].value=operate;

alert(document.forms[0].elements["operate"].value);

document.forms[0].submit();

//document.forms[0].action = "calc.do?operation=display";

//document.forms[0].submit();

}

</script>

</head>

<body>

<html:form action="/calc.do" method="post">

第一个数 : <html:text property="num1"/><html:errors property="error1"/><br/>

第二个数 : <html:text property="num2"/><html:errors property="error2"/><br/>

<html:button property="button" value="加" onclick="doSubmit('doAdd')" />

<html:button property="button" value="减" onclick="doSubmit('doSubtract')"/>

<html:button property="button" value="乘" onclick="doSubmit('doMultiply')"/>

<html:button property="button" value="除" onclick="doSubmit('doDivide')"/>

<html:reset property="reset" value="清除"></html:reset>

</html:form>

</body>

</html:html>

CalcForm.java代码如下

* Generated by MyEclipse Struts

* Template path: templates/java/JavaClass.vtl

package cn.form;

import javax.servlet.http.HttpServletRequest;

import org.apache.struts.action.ActionErrors;

import org.apache.struts.action.ActionForm;

import org.apache.struts.action.ActionMapping;

import org.apache.struts.action.ActionMessages;

import org.apache.struts.action.ActionMessage;

import org.apache.struts.action.ActionErrors;

import org.apache.struts.action.ActionError;

import org.apache.*;

/**

* MyEclipse Struts

* Creation date: 03-22-2008

* XDoclet definition:

* @struts.form name="calcForm"

public class CalcForm extends ActionForm {

* Generated fields

/** num2 property */

private String num2;

/** num1 property */

private String num1;

* Generated Methods

/**

* Method validate

* @param mapping

* @param request

* @return ActionErrors

public ActionErrors validate(ActionMapping mapping,

HttpServletRequest request) {

// TODO Auto-generated method stub

ActionErrors errors=new ActionErrors();

if(this.getNum1().length()==0 || this.getNum2().length()==0 ){

errors.add("error1",new ActionMessage("errors.validate.number","第一个数"));

errors.add("error2",new ActionMessage("errors.validate.number","第二个数"));

}

return errors;

}

/**

* Method reset

* @param mapping

* @param request

public void reset(ActionMapping mapping, HttpServletRequest request) {

// TODO Auto-generated method stub

this.setNum1("");

this.setNum2("");

}

/**

* Returns the num2.

* @return String

public String getNum2() {

return num2;

}

/**

* Set the num2.

* @param num2 The num2 to set

public void setNum2(String num2) {

this.num2 = num2;

}

/**

* Returns the num1.

* @return String

public String getNum1() {

return num1;

}

/**

* Set the num1.

* @param num1 The num1 to set

public void setNum1(String num1) {

this.num1 = num1;

}

CalcAction.java代码如下：

* Generated by MyEclipse Struts

* Template path: templates/java/JavaClass.vtl

package cn.action;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

import org.apache.struts.action.ActionForm;

import org.apache.struts.action.ActionForward;

import org.apache.struts.action.ActionMapping;

import org.apache.struts.actions.DispatchAction;

import cn.form.CalcForm;

import org.apache.struts.action.ActionMessages;

import org.apache.struts.action.ActionMessage;

/**

*MyEclipseStruts

*Creationdate:03-22-2008

*XDocletdefinition:

*@struts.actionpath="/calc"name="calcForm"input="/result.jsp"scope="request"validate="true"

publicclass CalcAction extends DispatchAction {

* Generated Methods

privateintnum1=0;

privateintnum2=0;

//加

public ActionForward doAdd(ActionMapping mapping, ActionForm form,

HttpServletRequest request, HttpServletResponse response) {

CalcForm calcForm = (CalcForm) form;// TODO Auto-generated method stub

//ActionMessages errors=new ActionMessages();

HttpSession session=request.getSession();

session=request.getSession();

num1=Integer.parseInt(calcForm.getNum1());

num2=Integer.parseInt(calcForm.getNum2());

session.setAttribute("result", Integer.valueOf((num1+num2)));

return mapping.findForward("result");

}

//减

public ActionForward doSubtract(ActionMapping mapping, ActionForm form,

HttpServletRequest request, HttpServletResponse response) {

CalcForm calcForm = (CalcForm) form;// TODO Auto-generated method stub

HttpSession session=request.getSession();

session=request.getSession();

num1=Integer.parseInt(calcForm.getNum1());

num2=Integer.parseInt(calcForm.getNum2());

session.setAttribute("result", Integer.valueOf((num1-num2)));

return mapping.findForward("result");

}

//乘

public ActionForward doMultiply(ActionMapping mapping, ActionForm form,

HttpServletRequest request, HttpServletResponse response) {

CalcForm calcForm = (CalcForm) form;// TODO Auto-generated method stub

HttpSession session=request.getSession();

session=request.getSession();

num1=Integer.parseInt(calcForm.getNum1());

num2=Integer.parseInt(calcForm.getNum2());

session.setAttribute("result", Integer.valueOf((num1*num2)));

return mapping.findForward("result");

}

//除

public ActionForward doDivide(ActionMapping mapping, ActionForm form,

HttpServletRequest request, HttpServletResponse response) {

CalcForm calcForm = (CalcForm) form;// TODO Auto-generated method stub

ActionMessages errors=calcForm.validate(mapping, request);

if(Integer.parseInt(calcForm.getNum2())==0){

errors.add("error2", new ActionMessage("errors.validate.zero"));

super.saveErrors(request, errors);//调用ActionForm方法保存这个错误信息

return mapping.findForward("input");

}

HttpSession session=request.getSession();

session=request.getSession();

num1=Integer.parseInt(calcForm.getNum1());

num2=Integer.parseInt(calcForm.getNum2());

session.setAttribute("result", Integer.valueOf((num1/num2)));

return mapping.findForward("result");

}

Struts-config.xml配置如下：

<struts-config>

<data-sources />

<form-beans >

<form-bean name="calcForm" type="cn.form.CalcForm" />

</form-beans>

<global-exceptions />

<global-forwards />

<action-mappings >

<action

input="/input.jsp"//验证必须

attribute="calcForm"

name="calcForm"

path="/calc"

scope="request"

type="cn.action.CalcAction"

validate="true"//验证必须

parameter="operate">//DispatchAction必须

</action>

</action-mappings>

<message-resources parameter="cn.ApplicationResources" />

</struts-config>

资源文件:

errors.footer = </span>

errors.header = <spanstyle="color:red;">

errors.validate.number = {0}/u4E0D/u80FD/u4E3A/u7A7A,/u4E14/u5FC5/u987B/u4E3A/u6570/u5B57!

errors.validate.zero = /u9664/u6570/u4E0D/u80FD/u4E3A0!