Struts2 使用xslt返回xml

1.       Action其实是一个POJO,所以我们可以直接把Action生成一个XML.只要把Result Type设为xslt就可以了:

      <action name="XmlModel" class="cpu.XmlModelAction">

            <result name="success" type="xslt" />

      </action>

里面包含了Action的所有属性,还有Locale等信息. 可以在浏览器里输入http://localhost:8080/XXX/XXX/XmlModel.action来看.

 

2.       为了定制自己想要的XML,我们可以输入参数来输出自己想要的Action的某个属性(属性可以是一个List).

      <action name="XmlModel" class="cpu.XmlModelAction">

            <result name="success" type="xslt">

                  <param name=”exposedValue”>modelList</param>

            </result>

      </action>

 

3.       如果有多于一个属性呢.加个大括号围起来

      <action name="XmlModel" class="cpu.XmlModelAction">

            <result name="success" type="xslt">

                  <param name=”exposedValue”>{modelList, type}</param>

            </result>

</action>

 

4.       以上三个方法都是由Action 来控制生成格式.那么对于我们这种控制欲很强的人来说并不满足,最好是由我们自己来定义生成样子.那么这时我们就要做的就是在属性里生成一个org.w3c.dom.Document属性.注意:不要用org.dom4j.Document类.要不会出现转化错误,死得很惨.

      <action name="XmlModel" class="cpu.XmlModelAction">

      <result name="success" type="xslt">

            <param name="exposedValue">xmlDoc</param>

      </result>

</action>

上面的xmlDoc就是 Action里的org.w3c.dom.Document类型.

 

5.       我只会用并且非要用org.dom4j.Document类怎么办? 那就在最后转化成 org.w3c.dom.Document:

package zju.cs.lr.util;

 

import java.io.ByteArrayInputStream;

import java.io.IOException;

 

import javax.xml.parsers.DocumentBuilderFactory;

import javax.xml.parsers.ParserConfigurationException;

 

import org.xml.sax.SAXException;

 

public class XmlUtil {

 

      private XmlUtil() {

      }

 

      public static org.w3c.dom.Document XmlString2W3cDom(String xml)

                  throws SAXException, IOException, ParserConfigurationException {

            byte[] byteArray = xml.getBytes("UTF-8");

            ByteArrayInputStream baos = new ByteArrayInputStream(byteArray);

            DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();

            org.w3c.dom.Document doc = factory.newDocumentBuilder().parse(baos);

            return doc;

      }

 

      public static org.dom4j.Document W3c2Dom4j(org.w3c.dom.Document doc) {

            if (doc == null) {

                  return (null);

            }

            org.dom4j.io.DOMReader xmlReader = new org.dom4j.io.DOMReader();

            return (xmlReader.read(doc));

      }

 

} 

Action里加上一句: xmlDoc = Xmlutil.XmlString2W3cDom(dom4jDoc.asXML());

上面的xmlDoc就是 Action里的org.w3c.dom.Document类型.

 

6.       上面写一个类很烦,有没有更简单的方法? 还真有.这就用到了Java里interface的强大之处了.用org.dom4j.dom.DOMDocumentFactory()来建立Document.而不要用DocumentHelper.createDocument()来产生.最后直接cast一下.

 

    public String execute() throws UnsupportedEncodingException, ParserConfigurationException, SAXException, IOException {

       InfoCpuService cpuSvc = null;

       cpuSvc = (InfoCpuService) ServiceLocator.getInstance().getService(InfoCpuService.class);

 

       modelList = cpuSvc.getModels(prodBrand);

 

       log.info(ReflectionToStringBuilder.toString(this));

 

       org.dom4j.Document dom4jDoc = new org.dom4j.dom.DOMDocumentFactory().createDocument();

 

       // doc = DocumentHelper.createDocument();

       // Element root = DocumentHelper.createElement("root");

Element root = dom4jDoc.addElement("root");

       root.addAttribute("prodType", "CPU");

 

       for (Object o : modelList) {

           root.addElement("model").addAttribute("name", (String) o);

       }

 

       //xmlDoc = XmlUtil.XmlString2W3cDom(doc.asXML());

       xmlDoc = (Document) dom4jDoc;

 

        HttpServletResponse response = ServletActionContext.getResponse();

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

        response.setHeader("Cache-Control", "no-cache");

        

       return SUCCESS;

    }

 

其中三句代码是为了防止生成中文乱码

        HttpServletResponse response = ServletActionContext.getResponse();

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

        response.setHeader("Cache-Control", "no-cache");

如果配置后报：



javax.xml.transform.TransformerException: Operation not supported.错误；



可以创建 template.xml模板文件-其内容：



<?xml version="1.0" encoding="UTF-8"?>



    <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">



        <xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes"/>



        <xsl:template match="/">



            <xsl:copy-of select="*"/>



        </xsl:template>



    </xsl:stylesheet>



修改配置为：



<result name="monthCount" type="xslt">



   <param name="exposedValue">doc</param>



   <param name="location">/master/count/template.xml</param>



</result>