利用 JDK 自帶的 org.w3c.dom 進行對象, map 與 xml 的互相轉換

利用 JDK 自帶的 org.w3c.dom 進行對象,map 與 xml 的簡單互相轉換, 其中用到了一個工具類 Hutools 下面是hutools的maven依賴

<dependency>
	<groupId>cn.hutool</groupId>
	<artifactId>hutool-all</artifactId>
	<version>4.1.19</version>
</dependency>

下面是工具類

/**
 * xml 工具,基於 jdk 內置的 xml api
 * @author zcqshine
 * @date 2018/12/8
 */
@Slf4j
public class W3CXmlUtil {
    /**
     * Number 子類的類型名稱集合
     */
    private static final Set<String> NUMBER_CHILDREN_CLASS_NAME = new HashSet<>();

    static {
        NUMBER_CHILDREN_CLASS_NAME.add(Integer.class.getName());
        NUMBER_CHILDREN_CLASS_NAME.add(Float.class.getName());
        NUMBER_CHILDREN_CLASS_NAME.add(Short.class.getName());
        NUMBER_CHILDREN_CLASS_NAME.add(Double.class.getName());
        NUMBER_CHILDREN_CLASS_NAME.add(Long.class.getName());
        NUMBER_CHILDREN_CLASS_NAME.add(BigDecimal.class.getName());
        NUMBER_CHILDREN_CLASS_NAME.add(BigInteger.class.getName());
        NUMBER_CHILDREN_CLASS_NAME.add(int.class.getName());
        NUMBER_CHILDREN_CLASS_NAME.add(short.class.getName());
        NUMBER_CHILDREN_CLASS_NAME.add(float.class.getName());
        NUMBER_CHILDREN_CLASS_NAME.add(double.class.getName());
        NUMBER_CHILDREN_CLASS_NAME.add(long.class.getName());
    }

    /**
     * xml 字符串轉換爲 Object
     * @param xmlStr
     * @param clazz
     * @param <T>
     * @return
     * @throws Exception
     */
    public static <T> T readObjectFormXml(String xmlStr, Class<T> clazz) throws Exception {
        T t;
        if (xmlStr == null || xmlStr.trim().length() == 0){
            throw new IllegalArgumentException("XML content string is empty !");
        } else {
            try {
                t = clazz.newInstance();
                Document document = XmlUtil.parseXml(xmlStr);
                if (document != null){
                    Element element = document.getDocumentElement();
                    if (element != null){
                        NodeList nodeList = element.getChildNodes();
                        for (int i = 0; i<nodeList.getLength(); i++){
                            Node node = nodeList.item(i);
                            if (node instanceof Element){
                                String nodeName = node.getNodeName();
                                String nodeText = node.getTextContent();
                                try {
                                    Field field = t.getClass().getDeclaredField(nodeName);
                                    Method method = t.getClass().getMethod("set" + StrUtil.upperFirst(nodeName),field.getType());
                                    String fieldType = field.getGenericType().getTypeName();
                                    if (fieldType.equals(String.class.getName()) || fieldType.equals(char.class.getName())){
                                        method.invoke(t, nodeText);
                                    } else if (NUMBER_CHILDREN_CLASS_NAME.contains(fieldType) && NumberUtils.isCreatable(nodeText)){
                                        Number number = NumberUtils.createNumber(nodeText);
                                        method.invoke(t, number);
                                    } else if (fieldType.equals(Date.class.getName())){
                                        try {
                                            Date date = DateUtil.parse(nodeText);
                                            method.invoke(t, date);
                                        } catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException e) {
                                            log.info("字段:{} 不爲時間格式的字符串,放棄解析.", nodeText);
                                        }
                                    }
                                } catch (NoSuchFieldException | SecurityException e) {
                                    log.info("{}屬性不存在,繼續處理其餘屬性", nodeName);
                                }
                            }
                        }
                    }
                }
            } catch (InstantiationException | IllegalAccessException | NoSuchMethodException | InvocationTargetException e) {
                log.error("轉換 xml 字符串爲對象失敗. ",e);
                throw new Exception("parse xml to Bean failure.");
            }
        }
        return t;
    }

    /**
     * XML 字符串轉 TreeMap
     * @param xmlStr
     * @return
     */
    public static Map<String, String> xml2Map(String xmlStr){
        Map<String,String> map = new TreeMap<>();
        if (StrUtil.isBlank(xmlStr)){
            throw new IllegalArgumentException("xml is empty");
        }else{
            Document document = XmlUtil.parseXml(xmlStr);
            Element element = document.getDocumentElement();
            if (element != null){
                NodeList nodeList = element.getChildNodes();
                for (int i = 0; i < nodeList.getLength(); i++){
                    Node node = nodeList.item(i);
                    String nodeName = node.getNodeName();
                    String nodeText = node.getTextContent();
                    map.put(nodeName, nodeText);
                }
            }
        }
        return map;
    }

    /**
     * Object 轉 xml 字符串
     * @param t
     * @param <T>
     * @return
     */
    public static <T> String object2Xml(T t){
        try {
			//獲得 DOM 解析器的工廠實例
            DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
            //從 DOM 工廠中得到 DOM 解析器
            DocumentBuilder builder = factory.newDocumentBuilder();
            Document document = builder.newDocument();
            Element root = document.createElement("xml");
            document.appendChild(root);
            Class clazz = t.getClass();
            Field[] fields = clazz.getDeclaredFields();
            if (fields.length > 0){
                for (Field field : fields) {
                    field.setAccessible(true);
                    String fieldName = field.getName();
                    Element element = document.createElement(fieldName);
                    Object obj = field.get(t);
                    if (obj != null){
                        String value = String.valueOf(obj);
                        element.appendChild(document.createCDATASection(value));
                    }
                    root.appendChild(element);
                }
            }
            return XmlUtil.toStr(document);
        } catch (ParserConfigurationException | IllegalAccessException  e) {
            log.error("對象轉 XML 失敗. ", e);
        }
        return null;
    }

    /**
     * map 轉 xml
     * @param map
     * @return
     */
    public static <T> String map2Xml(Map<String, T> map){
        if (map != null && !map.isEmpty()){
            try {
                DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
                //從 DOM 工廠中得到 DOM 解析器
                DocumentBuilder builder = factory.newDocumentBuilder();
                Document document = builder.newDocument();
                Element root = document.createElement("xml");
                document.appendChild(root);
                map.entrySet().forEach(item -> {
                    String key = item.getKey();
                    T object = item.getValue();
                    String value = null;
                    if (object != null){
                        value = String.valueOf(object);
                    }
                    Element element = document.createElement(key);
                    element.appendChild(document.createCDATASection(value));
                    root.appendChild(element);
                });
                return XmlUtil.toStr(document);
            } catch (ParserConfigurationException e) {
                log.error("map轉 xml 失敗.", e);
            }
        }
        return null;
    }
}