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XML学习经验实例总结2，
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DTD约束
Book.dtd：
<!ELEMENT 书架 (书+)>
<!ELEMENT 书 (书名,价格,介绍)>
<!ELEMENT 书名 (#PCDATA)>
<!ELEMENT 价格 (#PCDATA)>
<!ELEMENT 介绍 (#PCDATA)> 为书名设置属性 name（必须）
<!ATTLIST 书名 name CDATA #required>
Book.xml:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE 书架
SYSTEM "book.dtd">
<书架>
<书>
<书名 name="wy">计算机科学与技术</书名>
<价格>36.0</价格>
<介绍>这本书很好</介绍>
</书>
<书>
<书名 name="ztt">科学管理课</书名>
<价格>30.0</价格>
<介绍>这本书挺好</介绍>
</书>
<书>
<书名 name="wu">李清照集注</书名>
<价格>60.0</价格>
<介绍>这本书非常好</介绍>
</书>
</书架>
Jaxp对xml进行DOM解析---读取
（1）获取XML中的书名
public void read() throws Exception {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.parse("src/book.xml");
NodeList list = document.getElementsByTagName("书名");
Node node = list.item(1);
String content = node.getTextContent();
System.out.println(content);
}
（2）获取所有的节点
public void read2() throws Exception {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.parse("src/book.xml");
Node root = document.getElementsByTagName("书架").item(0);
list(root);
}
private void list(Node root) {
if(root instanceof Element)
System.out.println(root.getNodeName());
NodeList list=root.getChildNodes();
for(int i=0;i<list.getLength();i++)
{
Node child=list.item(i);
list(child);
}
}
（3）获取文档中的属性
public void read3() throws Exception {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.parse("src/book.xml");
Element bookname =(Element) document.getElementsByTagName("书名").item(0);
String value=bookname.getAttribute("name");
System.out.println(value);
}
XML解析---增加
（1）默认在末尾添加节点
@Test
public void add() throws Exception
{
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.parse("src/book.xml");
//创建节点
Element ele=document.createElement("价格");
ele.setTextContent("10元");
//创建节点挂在第一个节点上
Element book=(Element)document.getElementsByTagName("书").item(0);
book.appendChild(ele);
//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/book.xml")));
}
（2） 在文档指定位置添加节点
@Test
public void add2() throws Exception {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.parse("src/book.xml");
// 创建节点
Element ele = document.createElement("价格");
ele.setTextContent("10元");
// 得到参考节点
Element refNode = (Element) document.getElementsByTagName("价格").item(0);
// 得到要挂的节点
Element book = (Element) document.getElementsByTagName("书").item(0);
// 往book节点的指定位置插孩子节点
book.insertBefore(ele,refNode);
// 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/book.xml")));
}
(3) 在文档中为标签添加属性
@Test
public void addAttr() throws Exception {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.parse("src/book.xml");
Element bookname = (Element) document.getElementsByTagName("书名")
.item(0);
bookname.setAttribute("name","wy");
TransformerFactory tffactory = TransformerFactory.newInstance();
Transformer tf = tffactory.newTransformer();
tf.transform(new DOMSource(document),new StreamResult(
new FileOutputStream("src/book.xml")));
}
删除
1.删除1
@Test
public void delete1() throws Exception {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.parse("src/book.xml");
// 得到要删除的节点
Element ele = (Element) document.getElementsByTagName("价格").item(0);
// 得到要删除的节点的父节点
Element book = (Element) document.getElementsByTagName("书").item(0);
// 父节点删除子节点
book.removeChild(ele);
TransformerFactory tffactory = TransformerFactory.newInstance();
Transformer tf = tffactory.newTransformer();
tf.transform(new DOMSource(document),new StreamResult(
new FileOutputStream("src/book.xml")));
}
(2)删除2
@Test
public void delete2() throws Exception {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.parse("src/book.xml");
// 得到要删除的节点
Element ele = (Element) document.getElementsByTagName("价格").item(0);
ele.getParentNode().getParentNode().removeChild(ele.getParentNode());
TransformerFactory tffactory = TransformerFactory.newInstance();
Transformer tf = tffactory.newTransformer();
tf.transform(new DOMSource(document),new StreamResult(
new FileOutputStream("src/book.xml")));
}
5更新
@Test
public void update() throws Exception
{
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.parse("src/book.xml");
Element ele=(Element)document.getElementsByTagName("价格").item(0);
ele.setTextContent("100元");
//把更新后的内存写到xml文档中去
TransformerFactory tffactory = TransformerFactory.newInstance();
Transformer tf = tffactory.newTransformer();
tf.transform(new DOMSource(document),new StreamResult(new FileOutputStream("src/book.xml")));
}
SAX解析XML
1.步骤：
//创建工厂
SAXParserFactory factory=SAXParserFactory.newInstance();
//得到解析器
SAXParser sp=factory.newSAXParser();
//得到读取器
XMLReader reader=sp.getXMLReader();
//设置内容处理器
reader.setContentHandler(new ListHandler());
//读取xml文档内容
reader.parse("src/book.xml");
