【dom4j】java解析XML

dom4j】java解析XML"/>

【dom4j】java解析XML

dom4j用于解析xml，可以对xml文件进行操作，dom4j官方地址为dom4j

下面将演示使用dom4j对文件进行增删改查操作

xml原始文件为

<students><student id="001"><name>绘梨衣</name><age>20</age><gender>女</gender></student><student id="002"><name>北原伊织</name><age>20</age><gender>男</gender></student>
</students>

查询操作

代码如下

    public void query() throws DocumentException {//得到解析器SAXReader reader = new SAXReader();//指定解析文件Document document = reader.read(new File("src/student.xml"));//获取根节点Element rootElement = document.getRootElement();//获取所有student元素List<Element> students = rootElement.elements("student");for (Element student : students) {List<Element> list = student.elements();for (Element element : list) {System.out.println(element.getText());}}}

这段代码将查询xml文件中的所有student，下面为控制台输出

 增加操作

    public void add() throws DocumentException, IOException {//得到解析器SAXReader reader = new SAXReader();//指定解析文件Document document = reader.read(new File("src/student.xml"));//得到根节点Element rootElement = document.getRootElement();//创建一个新的student节点Element newElement = DocumentHelper.createElement("student");//为student节点添加属性newElement.addAttribute("id", "003");//创建student的子节点Element name = DocumentHelper.createElement("name");name.setText("路飞");Element age = DocumentHelper.createElement("age");age.setText("18");Element gender = DocumentHelper.createElement("gender");gender.setText("男");//将创建的子节点加入student中newElement.add(name);newElement.add(age);newElement.add(gender);rootElement.add(newElement);//将xml进行更新XMLWriter xmlWriter = new XMLWriter(new FileWriter("src/student.xml"));xmlWriter.write(document);xmlWriter.close();}

这端代码将添加一个新的student，并且student拥有name，age，gender元素，还有一个id属性,运行后的xml文件为

<students><student id="001"><name>绘梨衣</name><age>20</age><gender>女</gender></student><student id="002"><name>北原伊织</name><age>20</age><gender>男</gender></student><student id="003"><name>路飞</name><age>18</age><gender>男</gender></student>
</students>

更新操作

    public void update() throws DocumentException, IOException {//得到解析器SAXReader reader = new SAXReader();//指定解析文件Document document = reader.read(new File("src/student.xml"));//通过xpath进行查询Element age = (Element) document.selectSingleNode("//students//student[@id='003']//age");age.setText("20");//将xml进行更新XMLWriter xmlWriter = new XMLWriter(new FileWriter("src/student.xml"));xmlWriter.write(document);xmlWriter.close();}

这段代码使用xpath进行查询(注意：使用xpath需要引入一个jaxen包，链接为jaxen)，将student中id为003的age更新为20。更新后xml文件为

<students><student id="001"><name>绘梨衣</name><age>20</age><gender>女</gender></student><student id="002"><name>北原伊织</name><age>20</age><gender>男</gender></student><student id="003"><name>路飞</name><age>20</age><gender>男</gender></student>
</students>

删除操作

    public void delete() throws DocumentException, IOException {//得到解析器SAXReader reader = new SAXReader();//指定解析文件Document document = reader.read(new File("src/student.xml"));//通过xpath进行查询Element student = (Element) document.selectSingleNode("//students//student[@id='003']");//将该student删除student.getParent().remove(student);//将xml进行更新XMLWriter xmlWriter = new XMLWriter(new FileWriter("src/student.xml"));xmlWriter.write(document);xmlWriter.close();}

这段代码使用xpath找到student中id为003的，并将其删除。删除后的结果为

<students><student id="001"><name>绘梨衣</name><age>20</age><gender>女</gender></student><student id="002"><name>北原伊织</name><age>20</age><gender>男</gender></student>
</students>

总结

dom4j使用的并不多，会基本的增删改查即可，遇到不会的操作查询官方文档就行了，再一次的给出dom4j的官方网址dom4j