Struts 2 用XSLT输出XML响应

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(); 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");