dom4j使用

悠悠 2022-06-12 08:59 123阅读 0赞

引用大神的，特此加上原文链接：[http://blog.csdn.net/chenweitang123/article/details/6255108\#\_Toc288084410][http_blog.csdn.net_chenweitang123_article_details_6255108_Toc288084410]

### 1.读取XML文档： ###

读写XML文档主要依赖于org.dom4j.io包，有DOMReader和SAXReader两种方式。因为利用了相同的接口，它们的调用方式是一样的。  
**读取指定的xml文件之后返回一个Document对象，这个对象代表了整个XML文档，用于各种Dom运算。执照XML文件头所定义的编码来转换。**

public static Document load(String filename) {  
        Document document = null;  
        try {  
            SAXReader saxReader = new SAXReader();  
            document = saxReader.read(new File(filename)); // 读取XML文件,获得document对象 
        } catch (Exception ex) {  
            ex.printStackTrace();  
        }  
        return document;  
    }  
    
    public static Document load(URL url) {  
        Document document = null;  
        try {  
            SAXReader saxReader = new SAXReader();  
            document = saxReader.read(url); // 读取XML文件,获得document对象 
        } catch (Exception ex) {  
            ex.printStackTrace();  
        }  
        return document;  
    }

### 2.获取根节点 ###

根节点是xml分析的开始，任何xml分析工作都需要从根开始

Xml xml = new Xml();  
    
    Document dom = xml.load(path + "/" + file);  
    
    Element root = dom.getRootElement();

### 3. 新增一个节点以及其下的子节点与数据 ###

Element menuElement = root.addElement("menu");
    
    Element engNameElement = menuElement.addElement("engName");
    
    engNameElement.setText(catNameEn);
    
    Element chiNameElement = menuElement.addElement("chiName");
    
    chiNameElement.setText(catName);

### 4.写入XML文件 ###

注意文件操作的包装类是乱码的根源

public static boolean doc2XmlFile(Document document, String filename) {  
        boolean flag = true;  
        try {  
            XMLWriter writer = new XMLWriter(new OutputStreamWriter(  
                    new FileOutputStream(filename), "UTF-8"));  
            writer.write(document);  
            writer.close();  
        } catch (Exception ex) {  
            flag = false;  
            ex.printStackTrace();  
        }  
        System.out.println(flag);  
        return flag;  
    }

Dom4j通过XMLWriter将Document对象表示的XML树写入指定的文件，并使用OutputFormat格式对象指定写入的风格和编码方法。调用OutputFormat.createPrettyPrint()方法可以获得一个默认的pretty print风格的格式对象。对OutputFormat对象调用setEncoding()方法可以指定XML文件的编码方法。

public void writeTo(OutputStream out, String encoding)  
            throws UnsupportedEncodingException, IOException {  
        OutputFormat format = OutputFormat.createPrettyPrint();  
    
        format.setEncoding("gb2312");  
    
        XMLWriter writer = new XMLWriter(System.out, format);  
    
        writer.write(doc);  
    
        writer.flush();  
    
        return;  
    
    }

### 5.遍历xml节点 ###

对Document对象调用getRootElement()方法可以返回代表根节点的Element对象。拥有了一个Element对象后，可以对该对象调用elementIterator()方法获得它的子节点的Element对象们的一个迭代器。使用(Element)iterator.next()方法遍历一个iterator并把每个取出的元素转化为Element类型。

public boolean isOnly(String catNameEn, HttpServletRequest request,  
            String xml) {  
        boolean flag = true;  
        String path = request.getRealPath("");  
        Document doc = load(path + "/" + xml);  
        Element root = doc.getRootElement();  
        for (Iterator i = root.elementIterator(); i.hasNext();) {  
            Element el = (Element) i.next();  
            if (catNameEn.equals(el.elementTextTrim("engName"))) {  
                flag = false;  
                break;  
            }  
        }  
        return flag;  
    }

### 6.创建xml文件 ###

public static void main(String args[]) {  
    
        String fileName = "c:/text.xml";  
    
        Document document = DocumentHelper.createDocument();// 建立document对象，用来操作xml文件 
    
        Element booksElement = document.addElement("books");// 建立根节点 
    
        booksElement.addComment("This is a test for dom4j ");// 加入一行注释 
    
        Element bookElement = booksElement.addElement("book");// 添加一个book节点 
    
        bookElement.addAttribute("show", "yes");// 添加属性内容 
    
        Element titleElement = bookElement.addElement("title");// 添加文本节点 
    
        titleElement.setText("ajax in action");// 添加文本内容 
    
        try {  
    
            XMLWriter writer = new XMLWriter(new FileWriter(new File(fileName)));  
    
            writer.close();  
    
        } catch (Exception e) {  
    
            e.printStackTrace();  
    
        }  
    
    }

### 7.修改节点属性 ###

public static void modifyXMLFile() {  
    
        String oldStr = "c:/text.xml";  
    
        String newStr = "c:/text1.xml";  
    
        Document document = null;  
    
        //修改节点的属性 
    
        try {  
    
        SAXReader saxReader = new SAXReader(); // 用来读取xml文档 
    
        document = saxReader.read(new File(oldStr)); // 读取xml文档 
    
        List list = document.selectNodes("/books/book/@show");// 用xpath查找节点book的属性 
    
        Iterator iter = list.iterator();  
    
        while (iter.hasNext()) {  
    
        Attribute attribute = (Attribute) iter.next();  
    
        if (attribute.getValue().equals("yes"))   
    
            attribute.setValue("no");  
    
        }  
    
        } catch (Exception e) {  
    
            e.printStackTrace();  
    
        }  
    
        //修改节点的内容 
    
        try {  
    
        SAXReader saxReader = new SAXReader(); // 用来读取xml文档 
    
        document = saxReader.read(new File(oldStr)); // 读取xml文档 
    
        List list = document.selectNodes("/books/book/title");// 用xpath查找节点book的内容 
    
        Iterator iter = list.iterator();  
    
        while (iter.hasNext()) {  
    
        Element element = (Element) iter.next();  
    
        element.setText("xxx");// 设置相应的内容 
    
        }  
    
        } catch (Exception e) {  
    
            e.printStackTrace();  
    
        }  
    
    
    
        try {  
    
        XMLWriter writer = new XMLWriter(new FileWriter(new File(newStr)));  
    
        writer.write(document);  
    
        writer.close();  
    
        } catch (Exception ex) {  
    
            ex.printStackTrace();  
    
        }  
    
    }

### 8.删除节点 ###

public static void removeNode() {  
    
        String oldStr = "c:/text.xml";  
    
        String newStr = "c:/text1.xml";  
    
        Document document = null;  
    
        try {  
    
            SAXReader saxReader = new SAXReader();// 用来读取xml文档 
    
            document = saxReader.read(new File(oldStr));// 读取xml文档 
    
            List list = document.selectNodes("/books/book");// 用xpath查找对象 
    
            Iterator iter = list.iterator();  
    
            while (iter.hasNext()) {  
    
                Element bookElement = (Element) iter.next();  
    
                // 创建迭代器，用来查找要删除的节点,迭代器相当于指针，指向book下所有的title节点 
    
                Iterator iterator = bookElement.elementIterator("title");  
    
                while (iterator.hasNext()) {  
    
                    Element titleElement = (Element) iterator.next();  
    
                    if (titleElement.getText().equals("ajax in action")) {  
    
                        bookElement.remove(titleElement);  
    
                    }  
    
                }  
    
            }  
    
        } catch (Exception e) {  
    
            e.printStackTrace();  
    
        }  
    
        try {  
    
            XMLWriter writer = new XMLWriter(new FileWriter(new File(newStr)));  
    
            writer.write(document);  
    
            writer.close();  
    
        } catch (Exception ex) {  
    
            ex.printStackTrace();  
    
        }  
    
    }

### 2、XML文档操作2 ###

### 2.1、Document对象相关 ###

#### 1、读取XML文件,获得document对象. ####

SAXReader reader = new SAXReader();  
    Document   document = reader.read(new File("input.xml"));

#### 2、解析XML形式的文本,得到document对象. ####

String text = "<members></members>";      
    Document document = DocumentHelper.parseText(text);

#### 3、主动创建document对象. ####

Document document = DocumentHelper.createDocument();      
    Element root = document.addElement("members");// 创建根节点

#### 9.添加一个CDATA节点. ####

Element contentElm = infoElm.addElement("content");      
    contentElm.addCDATA(diary.getContent());

### 2.3、属性相关. ###

#### 1.取得节点的指定的属性 ####

Element root=document.getRootElement();          
    Attribute attribute=root.attribute("size");    // 属性名name

#### 2.取得属性的文字 ####

String text=attribute.getText();    
    String text2=root.element("name").attributeValue("firstname");
    //这个是取得根节点下name字节点的firstname属性的值.

#### 3.遍历某节点的所有属性 ####

Element root=document.getRootElement();
    for(Iterator it=root.attributeIterator();it.hasNext();){
    Attribute attribute = (Attribute) it.next();
    String text=attribute.getText();
    System.out.println(text);
    }

#### 4.设置某节点的属性和文字. ####

newMemberElm.addAttribute("name", "sitinspring");

#### 5.设置属性的文字 ####

Attribute attribute=root.attribute("name");      
    attribute.setText("sitinspring");

#### 6.删除某属性 ####

Attribute attribute=root.attribute("size");// 属性名name 
    root.remove(attribute);

### 2.4、将文档写入XML文件. ###

#### 1.文档中全为英文,不设置编码,直接写入. ####

XMLWriter writer = new XMLWriter(new FileWriter("output.xml"));      
    writer.write(document);      
    writer.close();

#### 2.文档中含有中文,设置编码格式再写入. ####

OutputFormat format = OutputFormat.createPrettyPrint();
    format.setEncoding("GBK");    // 指定XML编码
    XMLWriter writer = new XMLWriter(new FileWriter("output.xml"),format);
    writer.write(document);
    writer.close();

### 2.5、字符串与XML的转换 ###

#### 1.将字符串转化为XML ####

String text = "<members> <member>sitinspring</member> </members>";      
    Document document = DocumentHelper.parseText(text);

### 2.将文档或节点的XML转化为字符串. ###

SAXReader reader = new SAXReader();
    Document document = reader.read(new File("input.xml"));
    Element root=document.getRootElement();
    String docXmlText=document.asXML();
    String rootXmlText=root.asXML();
    Element memberElm=root.element("member");
    String memberXmlText=memberElm.asXML();

[http_blog.csdn.net_chenweitang123_article_details_6255108_Toc288084410]: http://blog.csdn.net/chenweitang123/article/details/6255108#_Toc288084410