xml小项目学习笔记

表示层：

public class StudentUI {

	//入口
	public static void main(String[] args) throws Exception {
		input();
	}
	public static void input() throws Exception{

		Scanner scanner = new Scanner(System.in);
		System.out.print("学员的编号：");
		String id = scanner.nextLine();
		System.out.print("更新学员的姓名：");
		String name = scanner.nextLine();
		System.out.print("更新学员的年龄：");
		String age = scanner.nextLine();
		Student student = new Student();
		student.setId(id);
		student.setName(name);
		student.setAge(age);
		StudentDao studentDao = new StudentDao();
		studentDao.update(student);
		
		
		/*键盘输入学员信息
		Scanner scanner = new Scanner(System.in);
		System.out.print("查询学员的编号：");
		String id = scanner.nextLine();
		StudentDao studentDao = new StudentDao();
		studentDao.read(id);
		Scanner scanner = new Scanner(System.in);
		System.out.print("删除学员的编号：");
		String id = scanner.nextLine();
		StudentDao studentDao = new StudentDao();
		studentDao.delete(id);
		Scanner scanner = new Scanner(System.in);
		System.out.print("用户名：" );
		String name = scanner.nextLine();
		System.out.print("年龄：" );
		String age = scanner.nextLine();
		//封装成JavaBean对象
		Student student = new Student();
		student.setId(IdUtil.getId());
		student.setName(name);
		student.setAge(age);
		//调用Dao对象
		StudentDao studentDao = new StudentDao();
		boolean flag = studentDao.create(student);
		if(flag){
			System.out.println("操作成功");
		}else{
			System.out.println("操作失败");
		}
		*/
	}
}


工具：
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

public class IDUtil {
	
	public static  String getID() throws Exception
	{
		//
		BufferedReader br = new BufferedReader(new FileReader("src/day2/mode2/ui/id.txt"));
		String id = br.readLine();		
		int temp = Integer.parseInt(id)+1;  //(int 型)
		BufferedWriter bw = new BufferedWriter(new FileWriter("src/day2/mode2/ui/id.txt"));
		bw.write(temp+"");
		bw.flush();
		bw.close();
		
		return id;
	}

}

访问层：

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;
	}

}

数据层：

<?xml version="1.0" encoding="UTF-8"?>

<students> 
  <student id="2011100801"> 
    <name>keke</name>  
    <age>11</age> 
  </student> 
</students>

实体层

public class Student {
	private String id;
	private String name;
	private String age;
	public Student(){}
	public String getId() {
		return id;
	}
	public void setId(String id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) throws Exception {
		if(name.matches("[a-zA-Z]+")){
			this.name = name;
		}else{
			throw new Exception();
		}
	}
	public String getAge() {
		return age;
	}
	public void setAge(String age) throws Exception {
		if(age.matches("[0-9]+")){
			this.age = age;
		}else{
			throw new Exception();
		}
	}
}