Java parses xml using DOM

Recently, our project is configuring the color of the system interface, and uses java dom to parse xml files to automatically generate css. I checked some information online and listed the methods and examples of using DOM to parse XML documents in java in the article for my reference.

1. DOM (Document Object Model)

DOM is the official W3C standard for XML documents in a way unrelated to the platform and language. DOM is a set of nodes organized in hierarchies. Because it is based on information layers, DOM is regarded as tree-based or object-based. You can think of it as a DOM tree and operate XML documents through the relationship between nodes and nodes. However, DOM-based XML operations require loading the entire XML document to construct a hierarchy, which consumes a lot of resources.

The following XML file is used to generate the css interface.

                            #header                               margin-bottom:20px;             min-height: 70px;             padding: 28px 0px 0;             box-shadow: 0 5px 10px rgba(0, 0, 0, 0.4);             background-image: -moz-linear-gradient(top, rgba(255, 255, 255, 0.1) 0%, rgba(0, 0, 0, 0.1) 40%, rgba(0, 0, 0, 0.2) 98%, #FFFFFF 100%);                                   color-stop(40%, rgba(0, 0, 0, 0.1)), color-stop(98%, rgba(0, 0, 0, 0.2)),color-stop(100%, #FFFFFF));             background-image: -webkit-linear-gradient(top, rgba(255, 255, 255, 0.1) 0%, rgba(0, 0, 0, 0.1) 40%, rgba(0, 0, 0, 0.2) 98%, #FFFFFF 100%);             background-image: -o-linear-gradient(top, rgba(255, 255, 255, 0.1) 0%, rgba(0, 0, 0, 0.1) 40%, rgba(0, 0, 0, 0.2) 98%, #FFFFFF 100%);                filter: progid:DXImageTransform.Microsoft.Gradient(GradientType=0, StartColorStr='#22FFFFFF', EndColorStr='#33000000');             background-image: linear-gradient(to bottom, rgba(255, 255, 255, 0.1) 0%, rgba(0, 0, 0, 0.1) 40%, rgba(0, 0, 0, 0.2) 98%, #FFFFFF 100%);                               background-color:               

 

Java calls DOM to parse XML

                                  String IMPORTANT = "important";         String CSS_CLASS_ID = "cssClass_id";         String CONFIG_CSS = "configCss";         String INHERENT_CSS = "inherentCss";         String CSS_CLASS = "cssClass";         String WRAPPER = "    ";        Map<String, String>       CssStyleBuilderAdv(Map<String, String>         .cssElementMap =                                 buildCssFile(String currentTheme)                                 String rebuiltCss = ""         DocumentBuilderFactory domfac =                      DocumentBuilder domBuilder =             String cssTemplateUrl = SystemParameters.getConfigPath() + "/" + currentTheme + "/cssTemplate.xml";              File file =              InputStream is =              Document doc =             NodeList cssItemList = doc.getElementsByTagName("cssItem");               (cssItemList !=                   ( i = 0; i < cssItemList.getLength(); i++) {                       StringBuffer cssClassList =  StringBuffer();                       StringBuffer inherentCssList =  StringBuffer();                      StringBuffer configCssList =  StringBuffer();                       Node cssItem =                     NodeList childNodes = cssItem.getChildNodes();                        ( j = 0; j < childNodes.getLength(); j++) {                           StringBuffer cssClassItem =                          StringBuffer inherentCss =                          StringBuffer configCss =                          Node cssNode =                          (cssNode.getNodeType() ==                             NodeList elementNodes = cssNode.getChildNodes();                               ( z = 0; z < elementNodes.getLength(); z++) {                                  Node elementNode =                                  (elementNode.getNodeType() ==                                                                              cssClassItem.append(elementNode.getTextContent());                                          cssClassItem.append(",\n"                                                                                inherentCss.append(elementNode.getTextContent());                                          inherentCss.append("\n"                                                                               configCss = configCss.append(switchValueByAttrId(elementNode, configCss));                              rebuiltCss += cssClassList.toString().substring(0, cssClassList.length() - 2) + "{\n"                             + inherentCssList + configCssList + "}\n\n";            }              LOGGER.warn("ParserConfigurationException : "         }              LOGGER.warn("FileNotFoundException : "         }              LOGGER.warn("SAXException : "         }              LOGGER.warn("IOException : "           rebuiltCss;                                 String packageName = currentTheme.substring(0, 1).toLowerCase() + currentTheme.substring(1         String url = SystemParameters.getCssPath() + "/" + packageName + "/CSS_Build.css"                      File f =                               BufferedWriter output =  BufferedWriter(                 f.setWritable(               }                                       f.setWritable(                     BufferedWriter output =  BufferedWriter(                   }                      LOGGER.info("Create Failed"           }              LOGGER.warn("Exception : "                                 NamedNodeMap elementAttMap =         String attributeValue = elementAttMap.getNamedItem(CSS_CLASS_ID).getTextContent();          String importantValue = ""         String nodeTextContext = WRAPPER + elementNode.getTextContent() + " "          (elementAttMap.getNamedItem(IMPORTANT) !=              importantValue = "!important";           configCss.append(nodeTextContext + cssElementMap.get(attributeValue));            configCss.append(";\n"          configCss;   }