XML案例（使用JAXP进行DOM解析）

1.book.xml

<?xml version="1.0" encoding="UTF-8" standalone="no"?><书架>
<书>
<书名 name="sss">Java就业培训教程</书名>
<作者>张孝祥</作者>

<售价>109元</售价>
<售价>59.00元</售价>
<售价>1.00元</售价>
</书>
</书架>

package cn.itcast.xml;

import java.io.FileOutputStream;
import java.util.List;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.junit.Test;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

//使用dom方式对xml文档进行crud
public class Demo2 {
@Test
public void read1() throws Exception {
// 1.创建工厂
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();

// 2.得到dom解析器
DocumentBuilder builder = factory.newDocumentBuilder();

// 3.解析xml文档，得到代表文档的document
Document document = builder.parse("src/cn/itcast/xml/book.xml");

NodeList list = document.getElementsByTagName("书名");
Node node = list.item(0);
String content = node.getTextContent();
System.out.println(content);
}

// 得到xml文档中的所有标签
@Test
public void read2() throws Exception {
// 1.创建工厂
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
// 2.得到dom解析器
DocumentBuilder builder = factory.newDocumentBuilder();
// 3.解析xml文档，得到代表文档的document
Document document = builder.parse("src/cn/itcast/xml/book.xml");
// 得到根节点
Node root = document.getElementsByTagName("书架").item(0);
list(root);
}

private void list(Node node) {
if (node instanceof Element) {
System.out.println(node.getNodeName());
}
NodeList list = node.getChildNodes();
for (int i = 0; i < list.getLength(); i++) {
Node child = list.item(i);
list(child);
}
}

// 得到xml文档中标签属性
@Test
public void read3() throws Exception {
// 1.创建工厂
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
// 2.得到dom解析器
DocumentBuilder builder = factory.newDocumentBuilder();
// 3.解析xml文档，得到代表文档的document
Document document = builder.parse("src/cn/itcast/xml/book.xml");
// 得到根节点
Element bookname = (Element) document.getElementsByTagName("书名")
.item(0);
String value = bookname.getAttribute("name");
System.out.println(value);
}

// 向xml文档中添加节点:<售价>1.00</售价>
@Test
public void add() throws Exception {
// 1.创建工厂
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
// 2.得到dom解析器
DocumentBuilder builder = factory.newDocumentBuilder();
// 3.解析xml文档，得到代表文档的document
Document document = builder.parse("src/cn/itcast/xml/book.xml");

// 创建节点
Element price = document.createElement("售价");
price.setTextContent("1.00元");

// 把创建的节点挂到第一本书上
Element book = (Element) document.getElementsByTagName("书").item(0);
book.appendChild(price);

// 把更新后内存写回到xml文档
TransformerFactory tffactory = TransformerFactory.newInstance();
Transformer tf = tffactory.newTransformer();
tf.transform(new DOMSource(document), new StreamResult(
new FileOutputStream("src/cn/itcast/xml/book.xml")));

}

// 向xml文档中指定位置上添加节点:<售价>20.00</售价>
@Test
public void add1() throws Exception {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.parse("src/cn/itcast/xml/book.xml");

// 创建节点
Element price = document.createElement("售价");
price.setTextContent("20.00元");

// 得到参考节点
Element refNode = (Element) document.getElementsByTagName("售价").item(1);

// 得到要挂载的节点
Element book = (Element) document.getElementsByTagName("书").item(0);
// 往book节点的指定位置插入
book.insertBefore(price, refNode);

}

// 向xml文档节点上添加属性:<书名>Java就业培训教程</书名>上添加name="sss"
@Test
public void addAttr() throws Exception {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.parse("src/cn/itcast/xml/book.xml");

Element bookname = (Element) document.getElementsByTagName("书名")
.item(0);
bookname.setAttribute("name", "sss");

//删除节点
@Test
public void delete() throws Exception {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.parse("src/cn/itcast/xml/book.xml");

// 得到要删除的节点
Element e = (Element) document.getElementsByTagName("售价").item(0);
//方法一：e.getParentNode().removeChild(e);

//方法二：
// 得到要删除节点的父节点
Element book = (Element) document.getElementsByTagName("书").item(0);
// 父节点删除子节点
book.removeChild(e);

}

//更新价格
@Test
public void update() throws Exception {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.parse("src/cn/itcast/xml/book.xml");

Element e = (Element) document.getElementsByTagName("售价").item(0);
e.setTextContent("109元");

// 把更新后内存写回到xml文档
TransformerFactory tffactory = TransformerFactory.newInstance();
Transformer tf = tffactory.newTransformer();
tf.transform(new DOMSource(document), new StreamResult(
new FileOutputStream("src/cn/itcast/xml/book.xml")));

}
}