对SAX解析XML的几个封装方法

最新推荐文章于 2021-03-12 06:53:53 发布

原创最新推荐文章于 2021-03-12 06:53:53 发布 · 1.3k 阅读

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文章标签：

#xml #string #null #parsing #exception #list

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本文提供了一种从URL加载XML文档并获取其根节点的方法。此外，还介绍了如何通过一系列实用函数来提取子节点的值和属性，这些函数可以方便地应用于各种XML解析任务。

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呵呵,从PetStore的代码中找到的,感觉方便很多.

1.获取根节点

public Element loadDocument(URL url) {
        Document doc = null;
        try {
            InputSource xmlInp = new InputSource(url.openStream());

            DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory.newInstance();
            DocumentBuilder parser = docBuilderFactory.newDocumentBuilder();
            doc = parser.parse(xmlInp);
            Element root = doc.getDocumentElement();
            root.normalize();
            return root;
        } catch (SAXParseException err) {
            System.out.println ("SignOnDAO ** Parsing error" + ", line " +
                        err.getLineNumber () + ", uri " + err.getSystemId ());
            System.out.println("SignOnDAO error: " + err.getMessage ());
        } catch (SAXException e) {
            System.out.println("SignOnDAO error: " + e);
        } catch (java.net.MalformedURLException mfx) {
            System.out.println("SignOnDAO error: " + mfx);
        } catch (java.io.IOException e) {
            System.out.println("SignOnDAO error: " + e);
        } catch (Exception pce) {
            System.out.println("SignOnDAO error: " + pce);
        }
        return null;
    }

2.获取子节点值和属性的几个方法:

//获取某个子节点的属性

public String getSubTagAttribute(Element root, String tagName, String subTagName, String attribute) {
        String returnString = "";
        NodeList list = root.getElementsByTagName(tagName);
        for (int loop = 0; loop < list.getLength(); loop++) {
            Node node = list.item(loop);
            if (node != null) {
                NodeList children = node.getChildNodes();
                for (int innerLoop =0; innerLoop < children.getLength(); innerLoop++) {
                    Node child = children.item(innerLoop);
                    if ((child != null) && (child.getNodeName() != null) && child.getNodeName().equals(subTagName) ) {
                        if (child instanceof Element) {
                            return ((Element)child).getAttribute(attribute);
                        }
                    }
                } // end inner loop
            }
        }
        return returnString;
    }

//获取子节点的值,重载的几个函数

public String getSubTagValue(Node node, String subTagName) {
        String returnString = "";
        if (node != null) {
            NodeList children = node.getChildNodes();
            for (int innerLoop =0; innerLoop < children.getLength(); innerLoop++) {
                Node child = children.item(innerLoop);
                if ((child != null) && (child.getNodeName() != null) && child.getNodeName().equals(subTagName) ) {
                    Node grandChild = child.getFirstChild();
                    if (grandChild.getNodeValue() != null) return grandChild.getNodeValue();
                }
            } // end inner loop
        }
        return returnString;
    }

   pubic String getSubTagValue(Element root, String tagName, String subTagName) {
        String returnString = "";
        NodeList list = root.getElementsByTagName(tagName);
        for (int loop = 0; loop < list.getLength(); loop++) {
            Node node = list.item(loop);
            if (node != null) {
                NodeList children = node.getChildNodes();
                for (int innerLoop =0; innerLoop < children.getLength(); innerLoop++) {
                    Node child = children.item(innerLoop);
                    if ((child != null) && (child.getNodeName() != null) && child.getNodeName().equals(subTagName) ) {
                        Node grandChild = child.getFirstChild();
                        if (grandChild.getNodeValue() != null) return grandChild.getNodeValue();
                    }
                } // end inner loop
            }
        }
        return returnString;
    }

public String getTagValue(Element root, String tagName) {
        String returnString = "";
        NodeList list = root.getElementsByTagName(tagName);
        for (int loop = 0; loop < list.getLength(); loop++) {
            Node node = list.item(loop);
            if (node != null) {
                Node child = node.getFirstChild();
                if ((child != null) && child.getNodeValue() != null) return child.getNodeValue();
            }
        }
        return returnString;
    }

最好做成一个工具类，以后用到就方便啦