每日日报

Dom解析

① 把整个文档先加载到内存中-> Document  所以可以对文档进行修改

② 如果文件比较大 可能会导致内存溢出

编程思路 DocumentBuilderFactory->DocumentBuilder->Document->通过节点获得NodeList->具体的Node

如果想修改 TransformerFactory->Transformer->transform(Souce, result)

public class DomParseTest {
2.    
3.    @Test
4.    public void domParse() throws Exception{
5.        //获取DocumentBuilderFactory
6.        DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
7.        //获取DocumentBuilder
8.        DocumentBuilder documentBuilder = builderFactory.newDocumentBuilder();
9.        //通过documentBuilder 解析xml文档获得Document对象
10.        Document document = documentBuilder.parse("book.xml");
11.        //通过元素的名字可以找到元素的集合
12.        NodeList nodeList = document.getElementsByTagName("售价");
13.        //nodeList.getLength();
14.        for(int i = 0;i<nodeList.getLength();i++){
15.            Node node = nodeList.item(i);
16.            String content = node.getTextContent();
17.            System.out.println(content);
18.        }
19.        //找到第二个元素
20.        Node node = nodeList.item(0);
21.        //读出对应节点的文本内容
22.        String content = node.getTextContent();
23.        System.out.println(content);
24.    }
25.
26.    @Test
27.    public void domModifyxml() throws Exception{
28.        DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
29.        DocumentBuilder builder = documentBuilderFactory.newDocumentBuilder();
30.        Document document = builder.parse("book.xml");
31.        NodeList nodeList = document.getElementsByTagName("售价");
32.        Node node = nodeList.item(1);
33.        //修改节点的内容
34.        node.setTextContent("199.00元");
35.        
36.        TransformerFactory transformerFactory = TransformerFactory.newInstance();
37.        Transformer transformer = transformerFactory.newTransformer();
38.        //数据源
39.        Source xmlSource = new DOMSource(document);
40.        //要输出到的目的地
41.        Result outputTarget = new StreamResult("book.xml");
42.        transformer.transform(xmlSource, outputTarget);
43.    }
44.}