用dom4解析XML并校验schema

解析并不难，schema校验比较麻烦，以下是全部代码

 private Document readXmlFromFile(File file) {
      Document protocolDoc = null;
      SAXReader reader = new SAXReader();
      XMLErrorHandler errorHandler = new XMLErrorHandler();
      SAXParserFactory factory = SAXParserFactory.newInstance();
      System.out.println(file.getAbsolutePath());
      factory.setValidating(true); // 要加入校验一定要写这句
      factory.setNamespaceAware(true);
      try {
         //先读取xml文件，再验证
         protocolDoc = reader.read(file);
         SAXParser parser = factory.newSAXParser();

         parser.setProperty("http://java.sun.com/xml/jaxp/properties/schemaLanguage",
               "http://www.w3.org/2001/XMLSchema");
         parser.setProperty("http://java.sun.com/xml/jaxp/properties/schemaSource", "file:"
               + this.getClass().getResource("/").getPath().toString() + PROTOCOL_XSD_FILE_NAME);

         SAXValidator validator = new SAXValidator(parser.getXMLReader());

         validator.setErrorHandler(errorHandler);

         validator.validate(protocolDoc);

         XMLWriter writer = new XMLWriter(OutputFormat.createPrettyPrint());

         //如果出错errorHandler会记录所有错误信息
         if (errorHandler.getErrors().hasContent()) {
            System.out.println("faild");
            //利用 dom4j 提供的 XMLWriter 打印出所有错误信息
            writer.write(errorHandler.getErrors());
            logger.error("validate xml schema on File " + file.getAbsolutePath() + " fail.");
            throw new ParseProtocolException("validate xml schema on File " + file.getAbsolutePath() + " fail.");
         }
      } catch (ParserConfigurationException e) {
         logger.error("Read xml From File " + file.getAbsolutePath() + " occur ParserConfigurationException.", e);
         throw new ParseProtocolException("Read xml From File " + file.getAbsolutePath()
               + " occur ParserConfigurationException.", e);
      } catch (SAXException e) {
         logger.error("Read xml From File " + file.getAbsolutePath() + " occur SAXException.", e);
         throw new ParseProtocolException("Read xml From File " + file.getAbsolutePath() + " occur SAXException.", e);
      } catch (UnsupportedEncodingException e) {
         logger.error("Read xml From File " + file.getAbsolutePath() + " occur UnsupportedEncodingException.", e);
         throw new ParseProtocolException("Read xml From File " + file.getAbsolutePath()
               + " occur UnsupportedEncodingException.", e);
      } catch (IOException e) {
         logger.error("Read xml From File " + file.getAbsolutePath() + " occur IOException.", e);
         throw new ParseProtocolException("Read xml From File " + file.getAbsolutePath() + " occur IOException.", e);
      } catch (DocumentException e) {
         logger.error("Read xml From File " + file.getAbsolutePath() + " occur DocumentException.", e);
         throw new ParseProtocolException("Read xml From File " + file.getAbsolutePath() + " occur DocumentException.",
               e);
      }
      return protocolDoc;
   }


      //以下是解析过程
      Document protocolDoc = readXmlFromFile(file);

      //得到根节点
      Element openremoteElement = protocolDoc.getRootElement();
      //遍历下面的子结点
      Iterator<Element> protocolItr = openremoteElement.elementIterator(PROTOCOL_ELEMENT_NAME);
      while (protocolItr.hasNext()) {
         Element protocolElement = protocolItr.next();
         ProtocolDefinition protocolDefinition = new ProtocolDefinition();
         // set protocol name
         // 获取节点中的属性
         protocolDefinition.setName(protocolElement.attributeValue(NAME_ATTR_NAME));

         // parse attr element start
         protocolDefinition.getAttrs().addAll(parseAttributs(protocolElement));
         map.put(protocolDefinition.getName(), protocolDefinition);
      }
      return map;