java笔记: Dom4j的使用Sax篇

    //获取第一个p1里面的属性id1的值
    public static void GetValue()throws Exception{
        //1.创建解析器
        SAXReader saxReader = new SAXReader();

        //2.得到document
        Document document = saxReader.read(PATH);

        //3.得到根目录
        Element rootElement = document.getRootElement();

        //4.得到p1标签
        Element p1 = rootElement.element("p1");

        //5.得到属性id1的值
        String id1 = p1.attributeValue("id");

        System.out.println("id:" + id1);

    }

    //删除某个元素p1标签下的age标签
    public static void DeleteAge() throws Exception{

        //1.创建解析器
        SAXReader saxReader = new SAXReader();

        //2.得到Document
        Document document = saxReader.read(PATH);

        //3.得到根目录
        Element root = document.getRootElement();

        //4.得到P1标签
        Element p1 = root.element("p1");

        //5. 得到age标签
        Element age = p1.element("age");

        //6.删除age标签
        p1.remove(age);

        //7. 回写XML
        OutputFormat format = OutputFormat.createCompactFormat();

        XMLWriter xmlWriter = new XMLWriter(new FileOutputStream(PATH),format);

        xmlWriter.write(document);

        xmlWriter.close();

    }

    //修改第一个p1下面的name元素的值
    public static void ChangeName() throws Exception{

        //1.创建解析器
        SAXReader saxReader = new SAXReader();

        //2.得到Document
        Document document = saxReader.read(PATH);

        //3.得到根ELEMENT
        Element root = document.getRootElement();

        //4.得到p1
        Element p1 = root.element("p1");

        //5. 得到 p1标签下的name标签
        Element name = p1.element("name");

        //6.更改标签的值
        //name.attributeValue("WangWu"); //错误的修改方式
        name.setText("WangWu");

        //7.回写XML
        OutputFormat outputFormat = new OutputFormat();

        XMLWriter xmlWriter = new XMLWriter(new FileOutputStream(PATH),outputFormat);

        xmlWriter.write(document);

        xmlWriter.close();

    }

    //在第一个p1下面的age标签之前添加<School>duchangerzhong</School>
    public static void AddSchool() throws Exception{

        //1. 创建解析器
        SAXReader saxReader = new SAXReader();

        //2.创建Document
        Document document = saxReader.read(PATH);

        //3.获取根Element
        Element root = document.getRootElement();

        //4.获取p1下所有的子元素
        Element p1 = root.element("p1");

        //5.获取p1下所有的子元素
        List list = p1.elements();

        //6.创建School元素
        Element school = DocumentHelper.createElement("school");

        school.setText("duchangerzhong");

        //7.在指定位置插入元素
        list.add(1,school);

        //list.add(list.size() - 1,school); //在末尾添加元素

        //回写XML
        OutputFormat outputFormat = new OutputFormat();

        XMLWriter writer = new XMLWriter(new FileOutputStream(PATH),outputFormat);

        writer.write(document);

        writer.close();


    }

    //在第一个p1标签末尾添加一个元素 <sex>nv</sex>
    public static void AddLastSex() throws Exception{

        //1. 创建解析器
        SAXReader saxReader = new SAXReader();

        //2. 创建Document
        Document document = saxReader.read(PATH);

        //3.获取根目录
        Element root = document.getRootElement();

        //4. 获取p1标签
        Element p1 = root.element("p1");

        //5.在p1标签内的末尾添加标签
        Element sex = p1.addElement("Sex");

        //6.给sex标签添加内容
        sex.setText("nv");

        //7.回写XML
        OutputFormat outputFormat = new OutputFormat();

        XMLWriter writer = new XMLWriter(new FileOutputStream(PATH),outputFormat);

        writer.write(document);

        writer.close();

    }

    //获取第二个name元素里面的值
    public static void GetSecondValue() throws Exception{
        //1.创建解析器
        SAXReader saxReader = new SAXReader();

        //2.获取Document
        Document document = saxReader.read(PATH);

        //3.获取根目录
        Element root = document.getRootElement();

        //4.获取根目录下所有的子元素
        List list1 = root.elements();

        //5.获取指定元素
        Element p1 = (Element) list1.get(1);

        //6.获取第二个p1下的name元素
        Element name = p1.element("name");

        String s = name.getText(); //获取标签中的值

        System.out.println("name标签中的值: " + s);


    }

    //查询xml中所有name元素的值
    public static void AllNameValue() throws Exception{

        //1.创建构造器
        SAXReader saxReader = new SAXReader();

        //获取Document
        Document document = saxReader.read(PATH);

        //获取根目录
        Element root = document.getRootElement();

        //获取根目录下所有的元素
        List<Element> list = root.elements();

        //遍历数据
        for (Element element:list){

            if (element.element("name") != null){
                Element name = element.element("name");

                System.out.println( name.getText());
            }else {
                System.out.println("本元素没有name子元素!");
            }
        }

    }