dom4j CURD

Love The Way You Lie 2021-09-11 00:34 290阅读 0赞

import java.io.File;  
import java.io.FileOutputStream;  
import java.io.OutputStream;  
import org.dom4j.Document;  
import org.dom4j.DocumentHelper;  
import org.dom4j.Element;  
import org.dom4j.io.OutputFormat;  
import org.dom4j.io.SAXReader;  
import org.dom4j.io.XMLWriter;  
import cn.itcast.xml.example3.domain.Student;  
  
  
public class StudentDao \{  
//根据编号更新学员信息  
public void update(Student student) throws Exception \{  
Document document = getDocument();  
String xpath = "//student\[@id='"+student.getId()+"'\]";  
Element element = (Element) document.selectSingleNode(xpath);  
if(element!=null)\{  
element.element("name").setText(student.getName());  
element.element("age").setText(student.getAge());  
write2xml(document);  
\}else\{  
System.out.println("查无此学员");  
\}  
  
  
\}  
//根据编号显示学员信息  
public void read(String id) throws Exception\{  
Document document = getDocument();  
String xpath = "//student\[@id='"+id+"'\]";  
Element element = (Element) document.selectSingleNode(xpath);  
if(element!=null)\{  
System.out.println("编号：" + element.attributeValue("id"));  
System.out.println("姓名：" + element.elementText("name"));  
System.out.println("年龄：" + element.elementText("age"));  
\}else\{  
System.out.println("查无此学员");  
\}  
\}  
//根据编号删除某位学员的信息  
public void delete(String id) throws Exception\{  
Document document = getDocument();  
String xpath = "//student\[@id='"+id+"'\]";  
Element element = (Element) document.selectSingleNode(xpath);  
if(element!=null)\{  
element.getParent().remove(element);  
write2xml(document);  
\}else\{  
System.out.println("查无此学员");  
\}  
\}  
//增加学员的信息  
public boolean create(Student student) throws Exception\{  
boolean flag = false;  
if(student!=null)\{  
Document document = null;  
try \{  
document = getDocument();  
\} catch (Exception e) \{  
//创建空XML文件  
document = DocumentHelper.createDocument();  
//创建<students>根元素  
document.addElement("students");  
\}  
Element rootElement = document.getRootElement();  
Element studentElement = rootElement.addElement("student");  
studentElement.addAttribute("id",student.getId());  
studentElement.addElement("name").setText(student.getName());  
studentElement.addElement("age").setText(student.getAge());  
write2xml(document);  
flag = true;  
\}  
return flag;  
\}  
//将内存中的Document写到硬盘  
private void write2xml(Document document) throws Exception \{  
OutputFormat format = OutputFormat.createPrettyPrint();  
OutputStream os = new FileOutputStream("src/cn/itcast/xml/example3/db/students.xml");  
XMLWriter xmlWriter = new XMLWriter(os,format);  
xmlWriter.write(document);  
xmlWriter.close();  
\}  
//取得Document对象  
private Document getDocument() throws Exception \{  
SAXReader saxReader = new SAXReader();  
Document document = saxReader.read(new File("src/cn/itcast/xml/example3/db/students.xml"));  
return document;  
\}  
  
  
\}