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成功实现了ajax--struts--spring无缝地结合构建

2007-01-30 11:34 295 查看
去年初,正好负责一个医药信息系统的设计开发,架构设计时,采用Struts+JDBC(自定义采用适配器模式封装了HashMap动态VO实现的持久层)。后来ajax热潮兴起,正好系统中有很多地方需要和服务器端交互数据,如采购销售系统中的订单头/订单明细等主从表结构的维护。

数据交互过程,我们考虑采用xml来组织数据结构,更新/保存:前台封装需要的xml,通过ajax提交---〉action解析xml ---〉改造原有的持久层实现xml持久化;

查询时:持久层根据实际需要返回xml,document对象,---〉action 处理 --〉前台自己封装js库来解析xml,并刷新部分页面。

ajax:已经有很多方法实现跨浏览器的方式,这里只介绍最简单的方式,同步模式下提交xmlStr给action(*.do)。

/**

* 将数据同步传递给后台请求url

*  @return 返回xmlhttp 响应的信息

*  @param-url = '/web/module/xxx.do?p1=YY&p2=RR';

*  @param-xmlStr:xml格式的字符串 <data><xpath><![CDATA[数据信息]]></xpath></data>

* @author zhipingch

* @date 2005-03-17

*/

function sendData(urlStr, xmlStr) {

var xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");

xmlhttp.open("POST", urlStr, false);

xmlhttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");

if (xmlStr) {

xmlhttp.send(xmlStr);

} else {

xmlhttp.send();

}

return xmlhttp.responseXml;

}

struts中我们扩展了Action,实现了xmlStr转化成document对象(dom4j),并且完善了转发方式。如:

1.DispatchAction

以一个Controller响应一组动作绝对是Controller界的真理,Struts的DispatchAction同样可以做到这点。

<action path="/admin/user" name="userForm" scope="request"
parameter="method" validate="false">

<forward name="list" path="/admin/userList.jsp"/>

</action>

其中parameter="method" 设置了用来指定响应方法名的url参数名为method,即/admin/user.do?method=list 将调用UserAction的public ActionForward list(....) 函数。 public ActionForward unspecified(....) 函数可以指定不带method方法时的默认方法。 但是这样需要在url后多传递参数method=list ;并且action节点配置中的parameter="method"也没有被充分利用,反而觉得是累赘! 因此我们直接在BaseDispatchAction中增加xml字符串解析,并充分利用action节点配置中的parameter="targetMethod" ,使得转发的时候,action能够直接转发到子类的相应方法中,减少了url参数传递,增强了配置信息可读性,方便团队开发。 同样以上述为例,扩展后的配置方式如下:

<action path="/admin/user" scope="request" parameter="list" validate="false">

<forward name="list" path="/admin/userList.jsp"/>

</action>

其中parameter="list" 设置了用来指定响应url=/admin/user.do的方法名,它将调用UserAction的public ActionForward list(....) 函数。

BaseDispatchDocumentAction 的代码如下,它做了三件重要的事情:

1、采用dom4j直接解析xml字符串,并返回document,如果没有提交xml数据,或者采用form形式提交的话,返回null;

2、采用模版方法处理系统异常,减少了子类中无尽的try{...}catch(){...};其中异常处理部分另作描述(你可以暂时去掉异常处理,实现xml提交和解析,如果你有兴趣,我们可以进一步交流);

3、提供了Spring配置Bean的直接调用,虽然她没有注入那么优雅,但是实现了ajax、struts、spring的结合。

BaseDispatchDocumentAction 的源码如下:

package com.ufida.haisheng.struts;

import java.io.IOException;

import java.io.PrintWriter;

import java.lang.reflect.InvocationTargetException;

import java.lang.reflect.Method;

import java.math.BigDecimal;

import java.sql.Timestamp;

import java.util.Date;

import java.util.HashMap;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

import org.apache.commons.beanutils.ConvertUtils;

import org.apache.commons.beanutils.converters.BigDecimalConverter;

import org.apache.commons.beanutils.converters.ClassConverter;

import org.apache.commons.beanutils.converters.IntegerConverter;

import org.apache.commons.beanutils.converters.LongConverter;

import org.apache.log4j.Logger;

import org.apache.struts.action.Action;

import org.apache.struts.action.ActionForm;

import org.apache.struts.action.ActionForward;

import org.apache.struts.action.ActionMapping;

import org.apache.struts.util.MessageResources;

import org.dom4j.Document;

import org.dom4j.io.SAXReader;

import org.hibernate.HibernateException;

import org.springframework.beans.BeansException;

import org.springframework.context.ApplicationContext;

import org.springframework.dao.DataAccessException;

import org.springframework.web.context.support.WebApplicationContextUtils;

import com.ufida.haisheng.constants.Globals;

import com.ufida.haisheng.converter.DateConverter;

import com.ufida.haisheng.converter.TimestampConverter;

import com.ufida.haisheng.exp.ExceptionDTO;

import com.ufida.haisheng.exp.ExceptionDisplayDTO;

import com.ufida.haisheng.exp.exceptionhandler.ExceptionHandlerFactory;

import com.ufida.haisheng.exp.exceptionhandler.ExceptionUtil;

import com.ufida.haisheng.exp.exceptionhandler.IExceptionHandler;

import com.ufida.haisheng.exp.exceptions.BaseAppException;

import com.ufida.haisheng.exp.exceptions.MappingConfigException;

import com.ufida.haisheng.exp.exceptions.NoSuchBeanConfigException;

/**

* 系统的Ajax转发基类。增加模版处理异常信息。

*

* @author 陈志平 chenzp

* @desc BaseDispatchDocumentAction.java

*

* @说明: web 应用基础平台

* @date 2005-03-02 11:18:01 AM

* @版权所有: All Right Reserved 2006-2008

*/

public abstract class BaseDispatchDocumentAction extends Action {

protected Class clazz = this.getClass();

protected static Logger log = Logger.getLogger(
BaseDispatchDocumentAction.class);

/**

* 异常信息

*/

protected static ThreadLocal<ExceptionDisplayDTO>
expDisplayDetails = new ThreadLocal<ExceptionDisplayDTO>();

private static final Long defaultLong = null;

private static ApplicationContext ctx = null;

/**

* 注册转换的工具类 使得From中的string --

* Model中的对应的类型(Date,BigDecimal,Timestamp,Double...)

*/

static {

ConvertUtils.register(new ClassConverter(), Double.class);

ConvertUtils.register(new DateConverter(), Date.class);

ConvertUtils.register(new DateConverter(), String.class);

ConvertUtils.register(new LongConverter(defaultLong), Long.class);

ConvertUtils.register(new IntegerConverter(defaultLong), Integer.class);

ConvertUtils.register(new TimestampConverter(), Timestamp.class);

ConvertUtils.register(new BigDecimalConverter(defaultLong),
BigDecimal.class);

}

/**

* The message resources for this package.

*/

protected static MessageResources messages =
MessageResources.getMessageResources("org.apache.struts.actions.LocalStrings");

/**

* The set of Method objects we have introspected for this class, keyed by

* method name. This collection is populated as different methods are

* called, so that introspection needs to occur only once per method name.

*/

protected HashMap<String, Method> methods = new HashMap<String, Method>();

/**

* The set of argument type classes for the reflected method call. These are

* the same for all calls, so calculate them only once.

*/

protected Class[] types = { ActionMapping.class, ActionForm.class,
Document.class, HttpServletRequest.class,

HttpServletResponse.class };

/**

* Process the specified HTTP request, and create the corresponding HTTP

* response (or forward to another web component that will create it).

* Return an <code>ActionForward</code> instance describing where and how

* control should be forwarded, or <code>null</code> if the response has

* already been completed.

*

* @param mapping

*            The ActionMapping used to select this instance

* @param form

*            The optional ActionForm bean for this request (if any)

* @param request

*            The HTTP request we are processing

* @param response

*            The HTTP response we are creating

*

* @exception Exception

*                if an exception occurs

*/

public ActionForward execute(ActionMapping mapping, ActionForm form,
HttpServletRequest request,

HttpServletResponse response) throws Exception {

response.setContentType("text/html; charset=UTF-8");

ExceptionDisplayDTO expDTO = null;

try {

Document doc = createDocumentFromRequest(request);

/*

* 这里直接调用mapping的parameter配置

*/

String actionMethod = mapping.getParameter();

/*

* 校验配置的方法是否正确、有效

*/

isValidMethod(actionMethod);

return dispatchMethod(mapping, form, doc, request,
response, actionMethod);

} catch (BaseAppException ex) {

expDTO = handlerException(request, response, ex);

} catch (Exception ex) {

ExceptionUtil.logException(this.getClass(), ex);

renderText(response,"[Error :对不起,系统出现错误了,
请向管理员报告以下异常信息./n" + ex.getMessage() + "]");

request.setAttribute(Globals.ERRORMSG, "对不起,
系统出现错误了,请向管理员报告以下异常信息./n" + ex.getMessage());

expDTO = handlerException(request,response, ex);

} finally {

expDisplayDetails.set(null);

}

return null == expDTO ? null : (expDTO.getActionForwardName() ==
null ? null : mapping.findForward(expDTO.getActionForwardName()));

}

/**

* 直接输出纯字符串

*/

public void renderText(HttpServletResponse response, String text) {

PrintWriter out = null;

try {

out = response.getWriter();

response.setContentType("text/plain;charset=UTF-8");

out.write(text);

} catch (IOException e) {

log.error(e);

} finally {

if (out != null) {

out.flush();

out.close();

out = null;

}

}

}

/**

* 直接输出纯HTML

*/

public void renderHtml(HttpServletResponse response, String text) {

PrintWriter out = null;

try {

out = response.getWriter();

response.setContentType("text/html;charset=UTF-8");

out.write(text);

} catch (IOException e) {

log.error(e);

} finally {

if (out != null) {

out.flush();

out.close();

out = null;

}

}

}

/**

* 直接输出纯XML

*/

public void renderXML(HttpServletResponse response, String text) {

PrintWriter out = null;

try {

out = response.getWriter();

response.setContentType("text/xml;charset=UTF-8");

out.write(text);

} catch (IOException e) {

log.error(e);

} finally {

if (out != null) {

out.flush();

out.close();

out = null;

}

}

}

/**

* 异常处理

* @param request

* @param out

* @param ex

* @return ExceptionDisplayDTO异常描述对象

*/

private ExceptionDisplayDTO handlerException(HttpServletRequest
request,HttpServletResponse response, Exception ex) {

ExceptionDisplayDTO expDTO = (ExceptionDisplayDTO)
expDisplayDetails.get();

if (null == expDTO) {

expDTO = new ExceptionDisplayDTO(null,this.getClass().getName());

}

IExceptionHandler expHandler =
ExceptionHandlerFactory.getInstance().create();

ExceptionDTO exDto = expHandler.handleException(expDTO.getContext(), ex);

request.setAttribute("ExceptionDTO", exDto);

renderText(response,"[Error:" + (exDto == null ?
"ExceptionDTO is null,请检查expinfo.xml配置文件." : exDto.getMessageCode())

+ "]");

return expDTO;

}

private void isValidMethod(String actionMethod) throws MappingConfigException {

if (actionMethod == null || "execute".equals(actionMethod) ||
"perform".equals(actionMethod)) {

log.error("[BaseDispatchAction->error] parameter = " + actionMethod);

expDisplayDetails.set(new ExceptionDisplayDTO(null,
"MappingConfigException"));

throw new MappingConfigException("对不起,
配置的方法名不能为 " + actionMethod);

}

}

/**

* 解析xml流

* @param request

* @return Document对象

*/

protected static Document createDocumentFromRequest(HttpServletRequest request)
throws Exception {

try {

request.setCharacterEncoding("UTF-8");

Document document = null;

SAXReader reader = new SAXReader();

document = reader.read(request.getInputStream());

return document;

} catch (Exception ex) {

log.warn("TIPS:没有提交获取XML格式数据流! ");

return null;

}

}

/**

* Dispatch to the specified method.

*

* @since Struts 1.1

*/

protected ActionForward dispatchMethod(ActionMapping mapping,
ActionForm form, Document doc,HttpServletRequest request,
HttpServletResponse response, String name) throws Exception {

Method method = null;

try {

method = getMethod(name);

} catch (NoSuchMethodException e) {

String message = messages.getMessage("dispatch.method",
mapping.getPath(), name);

log.error(message, e);

expDisplayDetails.set(new ExceptionDisplayDTO(null,
"MappingConfigException"));

throw new MappingConfigException(message, e);

}

ActionForward forward = null;

try {

Object args[] = { mapping, form, doc, request, response };

log.debug("[execute-begin] -> " + mapping.getPath() + "->
[" + clazz.getName() + "->" + name + "]");

forward = (ActionForward) method.invoke(this, args);

log.debug(" [execute-end] -> " + (null == forward ? "
use ajax send to html/htm" : forward.getPath()));

} catch (ClassCastException e) {

String message = messages.getMessage("dispatch.return",
mapping.getPath(), name);

log.error(message, e);

throw new BaseAppException(message, e);

} catch (IllegalAccessException e) {

String message = messages.getMessage("dispatch.error",
mapping.getPath(), name);

log.error(message, e);

throw new BaseAppException(message, e);

} catch (InvocationTargetException e) {

Throwable t = e.getTargetException();

String message = messages.getMessage("dispatch.error",
mapping.getPath(), name);

throw new BaseAppException(message, t);

}

return (forward);

}

/**

* Introspect the current class to identify a method of the specified name

* that accepts the same parameter types as the <code>execute</code>

* method does.

*

* @param name

*            Name of the method to be introspected

*

* @exception NoSuchMethodException

*                if no such method can be found

*/

protected Method getMethod(String name) throws NoSuchMethodException {

synchronized (methods) {

Method method = (Method) methods.get(name);

if (method == null) {

method = clazz.getMethod(name, types);

methods.put(name, method);

}

return (method);

}

}

/**

* 返回spring bean对象

* @param name Spring Bean的名称

* @exception BaseAppException

*/

protected Object getSpringBean(String name) throws BaseAppException {

if (ctx == null) {

ctx = WebApplicationContextUtils.getWebApplicationContext
(this.getServlet().getServletContext());

}

Object bean = null;

try {

bean = ctx.getBean(name);

} catch (BeansException ex) {

throw new NoSuchBeanConfigException("对不起,您没有配置名为:"
+ name + "的bean。请检查配置文件!", ex.getRootCause());

}

if (null == bean) {

throw new NoSuchBeanConfigException("对不起,您没有配置名为:"
+ name + "的bean。请检查配置文件!");

}

return bean;

}

}

开发人员只需要继承它就可以了,我们写个简单的示例action,如下:

/**

* 带Ajax提交xml数据的action类模版

*

* @author 陈志平 chenzp

*

* @说明: web 应用基础平台

* @date Aug 1, 2006 10:52:13 AM

* @版权所有: All Right Reserved 2006-2008

*/

public class UserAction extends BaseDispatchDocumentAction {

/**

* 这里 actionForm 和 doc 参数必有一个为空,请聪明的你分析一下

* @param mapping --转发的映射对象

* @param actionForm --仍然支持表单提交,此时doc == null

* @param doc document对象,解析xml后的文档对象

* @param request --请求

* @param response --响应

*/

public ActionForward list(ActionMapping mapping, ActionForm actionForm,
Document doc,HttpServletRequest request, HttpServletResponse response)
throws BaseAppException {

/**

* 转发的名称 userAction.search: 系统上下文 用于异常处理

*/

expDisplayDetails.set(new ExceptionDisplayDTO(null,
"userAction.search"));

/**

* 处理业务逻辑部分:

*

* 获取各种类型的参数 RequestUtil.getStrParameter(request,"ParameterName");

*

* 调用父类的 getSpringBean("serviceID")方法获取spring的配置bean

*

*/

UserManager userManager = (LogManager) getSpringBean("userManager");

//返回xml对象到前台

renderXML(response, userManager.findUsersByDoc(doc));

return null;

}

至此,我们成功实现了ajax--struts--spring的无缝结合。欢迎大家拍砖!
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