对xml常用操作做了简单封装

• 需要用到的包：
  
  • jaxen
  • dom4j

public class XMLUtils {

    //-----------------------------------------------------------------document start
    /*创建document*/
    public Document create_doc(){
        Document doc = createDocument();
        return doc;
    }

    /*从str转换到document*/
    public Document str_to_doc(String xmlStr) {
        Document document = null;
        try {
            document = parseText(xmlStr);
        } catch (DocumentException e) {
            e.printStackTrace();
        }
        return document;
    }

    /*从inputstream转换到document*/
    public Document is_to_doc(InputStream is){
        Document document = null;
        SAXReader saxReader = new SAXReader();
        try {
            document = saxReader.read(is);
        } catch (DocumentException e) {
            e.printStackTrace();
        }
        return document;
    }

    /*从XML文件转换到document*/
    public Document file_to_doc(String fileName) {
        SAXReader reader = new SAXReader();
        Document document = null;
        try {
            document = reader.read(new File(fileName));
        } catch (DocumentException e) {
            e.printStackTrace();
        }
        return document;
    }

    /*从URL流构建dom4j document对象*/
    public Document url_to_doc(URL url){
        Document document = null;
        try{
            SAXReader sr = new SAXReader();
            document = sr.read(url);
        } catch (DocumentException e) {
            e.printStackTrace();
        }
        return document;
    }

    /*将document转换为String*/
    public String xml_to_Str(Document doc) {
        String documentStr = doc.asXML();
        return documentStr.toString();
    }

    /*将Document写入到file*/
    public boolean write_to_file(Document doc,File file) throws IOException {
        boolean flag = true;
        OutputFormat outFmt = new OutputFormat();
        outFmt.setEncoding("UTF-8");
        XMLWriter writer = new XMLWriter(new FileOutputStream(file),outFmt);
        writer.write(doc);
        writer.close();
        return flag;
    }
    //------------------------------------------------------------------document end

    /*获得root元素，默认编码为utf-8*/
    public Element Ele_root(Document document) {
        return document.getRootElement();
    }

    /*根据节点名获得第一个子节点*/
    public List Ele_first(Element element){
        List list = new ArrayList<>();
        Iterator it = element.elementIterator();
        while(it.hasNext()){
            Element ele = (Element)it.next();
            list.add(ele.getName());
        }
        return list;
    }

    /*获取指定节点所有属性值*/
    public Map<String,String> Ele_attr(Element root,String xpath){
        HashMap map = new LinkedHashMap();
        List list = root.selectNodes("//" + xpath);
        Iterator it = list.iterator();
        while (it.hasNext()) {
            Element ele = (Element)it.next();
            for (Iterator i = ele.attributeIterator(); i.hasNext(); ) {
                Attribute attribute = (Attribute)i.next();
                map.put(attribute.getValue(),((Attribute) i.next()).getValue());
            }
        }
        return map;
    }

    /*获取指定节点列表*/
    public List Elelist(Element root,String xpath){
        List list = new ArrayList<Attribute>();
        List element = root.selectNodes("//" + xpath);
        Iterator it = element.iterator();
        while (it.hasNext()) {
            Element ele = (Element)it.next();
            //do something
            //attrs = getAttr(ele);
        }
        return list;
    }

    /*获取指定名称的属性---（Condition部分） ("//@op")*/
    public List getAttr(Element element){
        List list = new ArrayList<>();
        List arry = element.selectNodes("//@name | //@value");
        Iterator iter = arry.iterator();
        while(iter.hasNext()){
            Attribute attribute=(Attribute)iter.next();
            list.add(attribute.getData());
        }
        return list;
    }

    /*获取指定节点下所有子节点的信息*/
    public List Ele_list(Element element){
        List list = new ArrayList();
        Iterator it = element.elementIterator();
        while(it.hasNext()){
            Element ele = (Element)it.next();
            if(ele.elements().size() > 0)
                list.add(Ele_list(ele));
            else
                list.add(ele.getText());
        }
        return list;
    }

    /*获取指定节点下所有子节点的信息---返回list*/
    public List<Map> Ele_map(Element element){
        List list = new ArrayList<>();
        for (Iterator it = element.elementIterator(); it.hasNext(); ){
            Element ele = (Element)it.next();
            Map map = new HashMap<>();
            for (Iterator iterator = ele.elementIterator(); iterator.hasNext(); ){
                Element itter = (Element)iterator.next();
                map.put(itter.getName(),itter.getText());
            }
            list.add(map);
        }
        return list;
    }

    /*根据节点名称得到指定的子节点*/
    public Map Ele_child(Element element,String childName){
        Element ele = element.element(childName);
        Map map = new HashMap<>();
        for (Iterator iterator = ele.elementIterator(); iterator.hasNext(); ){
            Element itter = (Element)iterator.next();
            map.put(itter.getName(),itter.getText());
        }
        return map;
    }

    /*使用xpath获取指定节点*/
    public Map Ele_xPath(Element root,String nodePath) {
        Map map = new LinkedHashMap<>();
        Element ele = (Element) root.selectSingleNode(nodePath);
        List list = ele.elements();

        for (Object obj : list) {
            Element element = (Element) obj;
            map.put(element.getName(),element.getTextTrim());
        }
        return map;
    }

    /*判断节点是否还有子节点*/
    public boolean hasChildNode(Element element){
        if (null == element)
            return false;
        return element.hasContent();
    }

    /*去掉声明头*/
    public String cutDecHeader(String xmlStr){
        return xmlStr.replaceFirst("\\s*<[^<>]+>\\s*","");
    }
}

xml解析后，将解析的节点放到Map或者Array中。用到xpath获取指定节点下的内容。