xml的增删改查

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import java.io.FileOutputStream;

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;

public class Demo3 {

//读取xml文档中的标签
@Test
public void read() throws Exception{
  //1、创建工厂
  DocumentBuilderFactoryfactory=DocumentBuilderFactory.newInstance();
  //2、得到dom解析器
  DocumentBuilderbuilder=factory.newDocumentBuilder();
  //3、解析xml文档，得到代表文档的document
  Documentdocument=builder.parse("src/enumration/nan/book.xml");
  NodeListlist=document.getElementsByTagName_r("书名");
  Node node=list.item(0);
  Stringcontent=node.getTextContent();
  System.out.println(content);

}
@Test
public void test2() throws Exception{
  DocumentBuilderFactoryfactory=DocumentBuilderFactory.newInstance();
  DocumentBuilderbuilder=factory.newDocumentBuilder();
  Documentdocument=builder.parse("src/enumration/nan/book.xml");
  //得到根节点
  Noderoot=document.getElementsByTagName_r("书架").item(0);
  list(root);
}
private void list(Node node){
  if(node instanceofElement){
   System.out.println(node.getNodeName());
  }
  NodeListlist=node.getChildNodes();
  for(inti=0;i<list.getLength();i++){
   Nodechild=list.item(i);
   list(child);
  }
}

//得到xml文档中的标签属性值
@Test
public void test3() throws Exception{
  DocumentBuilderFactoryfactory=DocumentBuilderFactory.newInstance();
  DocumentBuilderbuilder=factory.newDocumentBuilder();
  Documentdocument=builder.parse("src/enumration/nan/book.xml");

  Element bookname=(Element)document.getElementsByTagName_r("书名").item(0);
  Stringname=bookname.getAttribute("name");
  System.out.println(name);
}

//向xml文档中添加结点：
@Test
public void add() throws Exception{
  DocumentBuilderFactoryfactory=DocumentBuilderFactory.newInstance();
  DocumentBuilderbuilder=factory.newDocumentBuilder();
  Documentdocument=builder.parse("src/enumration/nan/book.xml");
  //创建节点
  Elementprice=document.createElement_x("售价");
  price.setTextContent("59.00元");

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

  //把更新后内存写回到xml文档
  TransformerFactorytfactory=TransformerFactory.newInstance();
  Transformertf=tfactory.newTransformer();
  tf.transform(newDOMSource(document), new StreamResult(newFileOutputStream("src/enumration/nan/book.xml")));
}
//向xml文档中指定位置插入
@Test
public void add2() throws Exception{
  DocumentBuilderFactoryfactory=DocumentBuilderFactory.newInstance();
  DocumentBuilderbuilder=factory.newDocumentBuilder();
  Documentdocument=builder.parse("src/enumration/nan/book.xml");

  //创建节点
  Elementprice=document.createElement_x("售价");
  price.setTextContent("53.00元");

  //得到要参考节点
  Element refNode=(Element)document.getElementsByTagName_r("售价").item(0);

  //得到要挂孩子的节点
  Element book=(Element)document.getElementsByTagName_r("书").item(0);

  //往book节点的指定位置插入
  book.insertBefore(price,refNode);

  //把更新后内存写回到xml文档中

  TransformerFactorytfactory=TransformerFactory.newInstance();
  Transformertf=tfactory.newTransformer();
  tf.transform(newDOMSource(document), new StreamResult(newFileOutputStream("src/enumration/nan/book.xml")));
}

//向xml文档节点中添加属性：
@Test
public void addAttr() throws Exception{
  DocumentBuilderFactoryfactory=DocumentBuilderFactory.newInstance();
  DocumentBuilderbuilder=factory.newDocumentBuilder();
  Documentdocument=builder.parse("src/enumration/nan/book.xml");

  Element bookname=(Element)document.getElementsByTagName_r("书名").item(0);
  bookname.setAttribute("name","xxx");

  //把更新后内存写回到xml文档
  TransformerFactorytfactory=TransformerFactory.newInstance();
  Transformertf=tfactory.newTransformer();
  tf.transform(newDOMSource(document), new StreamResult(newFileOutputStream("src/enumration/nan/book.xml")));
}

@Test
public void delete() throws Exception{
  DocumentBuilderFactoryfactory=DocumentBuilderFactory.newInstance();
  DocumentBuilderbuilder=factory.newDocumentBuilder();
  Documentdocument=builder.parse("src/enumration/nan/book.xml");

  //得到要删除的节点
  Element e=(Element)document.getElementsByTagName_r("售价").item(0);

  //得到要删除的节点的父节点
  Element book=(Element)document.getElementsByTagName_r("书").item(0);

  //父节点再删孩子
  book.removeChild(e);

  //再把删除后的写回到内存中
  TransformerFactorytfactory=TransformerFactory.newInstance();
  Transformertf=tfactory.newTransformer();
  tf.transform(newDOMSource(document), new StreamResult(newFileOutputStream("src/enumration/nan/book.xml")));
}

//删整个xml文件
@Test
public void delete2() throws Exception{
  DocumentBuilderFactoryfactory=DocumentBuilderFactory.newInstance();
  DocumentBuilderbuilder=factory.newDocumentBuilder();
  Documentdocument=builder.parse("src/enumration/nan/book.xml");

  //得到要删除的节点
  Element e=(Element)document.getElementsByTagName_r("售价").item(0);
  //e.getParentNode().removeChild(e);
  //e.getParentNode().getParentNode().removeChild(e.getParentNode());这个是把书给删了
  e.getParentNode().getParentNode().getParentNode().removeChild(e.getParentNode().getParentNode());
  //把更新后写回到内存中
  TransformerFactorytfactory=TransformerFactory.newInstance();
  Transformertf=tfactory.newTransformer();
  tf.transform(newDOMSource(document), new StreamResult(newFileOutputStream("src/enumration/nan/book.xml")));
}

//更新xml文件
@Test
public void update() throws Exception{
  DocumentBuilderFactoryfactory=DocumentBuilderFactory.newInstance();
  DocumentBuilderbuilder=factory.newDocumentBuilder();
  Documentdocument=builder.parse("src/enumration/nan/book.xml");

  //得到要更新的数据
  Element price=(Element)document.getElementsByTagName_r("售价").item(0);

  price.setTextContent("109");

  //更新后写回到内存中
  TransformerFactorytfactory=TransformerFactory.newInstance();
  Transformertf=tfactory.newTransformer();
  tf.transform(newDOMSource(document), new StreamResult(newFileOutputStream("src/enumration/nan/book.xml")));

}
}

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