java解析xml

一.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

二.节点相关

 

1.获取文档的根节点.

Element rootElm = document.getRootElement();

2.取得某节点的单个子节点.

Element memberElm=root.element("member");// "member"是节点名

3.取得节点的文字

String text=memberElm.getText();

也可以用:

String text=root.elementText("name");这个是取得根节点下的name字节点的文字.

 

4.取得某节点下名为"member"的所有字节点并进行遍历.

List nodes = rootElm.elements("member");

 

for (Iterator it = nodes.iterator(); it.hasNext();) {

   Element elm = (Element) it.next();

   // do something

}

5.对某节点下的所有子节点进行遍历.

            for(Iterator it=root.elementIterator();it.hasNext();){

                Element element = (Element) it.next();

                // do something

            }

6.在某节点下添加子节点.

Element ageElm = newMemberElm.addElement("age");

7.设置节点文字.

ageElm.setText("29");

8.删除某节点.

parentElm.remove(childElm);// childElm是待删除的节点,parentElm是其父节点

三.属性相关.

1.取得某节点下的某属性

            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();

也可以用:

String text2=root.element("name").attributeValue("firstname");这个是取得根节点下name字节点的属性firstname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);

四.将文档写入XML文件.

1.文档中全为英文,不设置编码,直接写入的形式.

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

writer.write(document);

writer.close();

2.文档中含有中文,设置编码格式写入的形式.

            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();

五.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();

六.使用XPath快速找到节点.

读取的XML文档示例

<?xml version="1.0" encoding="UTF-8"?>

<projectDescription>

  <name>MemberManagement</name>

  <comment></comment>

  <projects>

    <project>PRJ1</project>

    <project>PRJ2</project>

    <project>PRJ3</project>

    <project>PRJ4</project>

  </projects>

  <buildSpec>

    <buildCommand>

      <name>org.eclipse.jdt.core.javabuilder</name>

      <arguments>

      </arguments>

    </buildCommand>

  </buildSpec>

  <natures>

    <nature>org.eclipse.jdt.core.javanature</nature>

  </natures>

</projectDescription>

 

使用XPath快速找到节点project.

 public static void main(String[] args){

    SAXReader reader = new SAXReader();

 

    try{

      Document doc = reader.read(new File("sample.xml"));

 

      List projects=doc.selectNodes("/projectDescription/projects/project");

 

      Iterator it=projects.iterator();

 

      while(it.hasNext()){

        Element elm=(Element)it.next();      

        System.out.println(elm.getText());

      }

 

    }

    catch(Exception ex){

       ex.printStackTrace();

    }

}

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