Java对XML的增删改查的一个例子 - 联系人操作

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效果：

 

   

一.准备XML

<?xml version="1.0" encoding="UTF-8" standalone="no"?><contacts>
	<user>
		<name>sam</name>
		<password>111111</password>
		<contacts>
			<contact>
				<name>nanana</name>
				<phone>234567</phone>
			</contact>
			<contact>
				<name>老干爹</name>
				<phone>222222</phone>
			</contact>
		</contacts>
	</user>
	<user>
		<name>jack</name>
		<password>111111</password>
		<contacts>
			<contact>
				<name>老干妈</name>
				<phone>1234556</phone>
			</contact>
		</contacts>
	</user>
</contacts>

二.一个联系人实体类

<?xml version="1.0" encoding="UTF-8" standalone="no"?><contacts>
	<user>
		<name>sam</name>
		<password>111111</password>
		<contacts>
			<contact>
				<name>nanana</name>
				<phone>234567</phone>
			</contact>
			<contact>
				<name>老干爹</name>
				<phone>222222</phone>
			</contact>
		</contacts>
	</user>
	<user>
		<name>jack</name>
		<password>111111</password>
		<contacts>
			<contact>
				<name>老干妈</name>
				<phone>1234556</phone>
			</contact>
		</contacts>
	</user>
</contacts>

三.程序入口

package cn.hncu.xml.contact;

import java.io.IOException;
import java.util.List;
import java.util.Scanner;

import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.xml.sax.SAXException;

/**
 * dos版
 * 对contacts.xml进行添删改查
 * 
 * 菜单：
 * 1.登录
 * 2.注册
 * 0.退出
 * 		登录成功后的菜单：
 * 		1.查找所有联系人
 * 		2.添加一个联系人
 * 		3.修改一个联系人
 * 		4.删除一个联系人
 * 		0.退出
 * @author BarryLee
 * @2018年8月21日@上午9:23:56
 */

public class Main {
	public static Document dom = null;
	public static Element root = null;
	public static Element curUser = null;//当前用户
	public static Scanner sc = new Scanner(System.in);
	public static final String fileName = "./xmls/contacts.xml";
	private static Service service = new Service();
	public static void main(String[] args) {
		System.out.println("******欢迎使用******");
		while(true) {
			printMenu1();
			String n = sc.next();
			switch (n) {
			case "1"://登录
				if(service.loginService()) {
					System.out.println("登录成功");
					loginSuccess();
				}else {
					System.out.println("登录失败");
				}
				System.out.println();
				break;
			case "2"://注册
				if(service.registerService()) {
					System.out.println("注册成功");
				}else {
					System.out.println("注册失败");
				}
				System.out.println();
				break;
			case "0"://退出系统
				return;
			default:
				System.out.println("请输入正确的指令");
				System.out.println();
			}
		}
	}
	public static void loginSuccess() {
		while(true) {
			printMenu2();
			String n = sc.next();
			switch (n) {
			case "1"://查找所有联系人
				List<Contact> list = service.getMyContactsService();
				Utils.printContact(list);
				break;
			case "2"://添加一个联系人
				if(service.addContactService()) {
					System.out.println("添加成功");
				}else {
					System.out.println("添加失败");
				}
				System.out.println();
				break;
			case "3"://修改一个联系人
				service.getMyContacts();
				if(service.modContactService()) {
					System.out.println("修改成功");
				}else {
					System.out.println("修改失败");
				}
				System.out.println();
				break;
			case "4"://删除一个联系人
				if(service.delContactService()) {
					System.out.println("删除成功");
				}else {
					System.out.println("删除失败");
				}
				System.out.println();
				break;
			case "0"://退出登录
				curUser = null;
				return ;
			default:
				System.out.println("请输入正确的指令");
			}
		}
	}
	public static void printMenu1() {
		System.out.println();
		System.out.println("请输入命令：");
		System.out.println("1.登录，2.注册，0.退出");
		System.out.print("->");
	}
	public static void printMenu2() {
		System.out.println();
		System.out.println("请输入命令：");
		System.out.println("1.查看所有联系人，2.添加一个联系人");
		System.out.println("3.修改一个联系人，4.删除一个联系人");
		System.out.println("0.退出登录");
		System.out.print("->");
	}
	
	static {
		try {
			//保证只有一个dom
			dom = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(fileName);
			root = (Element)dom.getFirstChild();
		} catch (SAXException | IOException | ParserConfigurationException e) {
			//e.printStackTrace();
		}
	}
	
}

	

四.Service层

package cn.hncu.xml.contact;

import java.util.List;
import java.util.Scanner;

public class Service {
	private Dao dao = new Dao();
	private Scanner sc = new Scanner(System.in);
	/**
	 * 登录
	 * @return
	 */
	public boolean loginService() {
		String[] user = getNamePwd();
		if (user != null) {
			return dao.login(user[0], user[1]);
		}
		return false;
	}

	/**
	 * 注册
	 * @return
	 */
	public boolean registerService() {
		String[] user = getNamePwd();
		if (user != null) {
			return dao.register(user[0], user[1]);
		}
		return false;
	}

	/**
	 * 获取用户名和密码 返回空时：输入错误 不为空时：[0]为用户名，[1]为密码
	 * @return
	 */
	public String[] getNamePwd() {
		// 用户名不允许空格，密码允许空格
		System.out.print("请输入用户名：");
		String name = sc.next();
		if (name == null || name.trim().length() == 0) {
			System.out.println("用户名不能为空");
			return null;
		}
		System.out.print("请输入用户密码：");
		String pwd = sc.next();
		if (pwd == null || pwd.length() == 0) {
			System.out.println("密码不能为空");
			return null;
		}
		return new String[] { name, pwd };
	}

	public String[] getNamePhone() {
		System.out.println("请输入用户名");
		String name = sc.next();
		if (name == null || name.trim().length() == 0) {
			System.out.println("用户名不能为空");
			return null;
		}
		System.out.println("请输入电话号码");
		String phone = sc.next();
		if (phone == null || phone.trim().length() == 0) {
			System.out.println("手机号不能为空");
			return null;
		}
		return new String[] { name, phone };
	}

	public List<Contact> getMyContactsService() {
		return getMyContacts();
	}

	public boolean addContactService() {
		String res[] = getNamePhone();
		if (res == null) {
			return false;
		}
		return dao.addContact(new Contact(res[0], res[1]));
	}

	public boolean modContactService() {
		System.out.print("请输入要修改的联系人的id->");
		int i = -1;
		try {
			i = Integer.parseInt(sc.next());
			if (i > 0 && i <= getMyContacts().size()) {
				String res[] = getNamePhone();
				if (res == null) {
					return false;
				}
				Contact contact = new Contact(res[0], res[1]);
				return dao.modContact(i - 1, contact);
			}
		} catch (NumberFormatException e) {
			//e.printStackTrace();
		}
		return false;
	}

	public boolean delContactService() {
		int i = -1;
		System.out.print("请输入要删除联系人的id->");
		try {
			i = Integer.parseInt(sc.next());
			if (i > 0 && i <= getMyContacts().size()) {
				return dao.delContact(i-1);
			}
		} catch (NumberFormatException e) {
			//e.printStackTrace();
		}
		return false;
	}

	public List<Contact> getMyContacts() {
		return dao.getMyContacts();
	}
}

五.DAO层

package cn.hncu.xml.contact;

import java.util.ArrayList;
import java.util.List;

import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactoryConfigurationError;

import org.w3c.dom.Element;
import org.w3c.dom.NodeList;

public class Dao {
	/**
	 * 根据用户名和密码进行登录
	 * 
	 * @param name
	 * @param pwd
	 */
	public boolean login(String name, String pwd) {
		try {
			NodeList list = Main.root.getElementsByTagName("user");
			// 遍历所有用户
			for (int i = 0; i < list.getLength(); i++) {
				String getName = ((Element) list.item(i)).getElementsByTagName("name").item(0).getTextContent();
				String getPwd = ((Element) list.item(i)).getElementsByTagName("password").item(0).getTextContent();
				if (getName.equals(name) && getPwd.equals(pwd)) {
					// 设置当前用户
					Main.curUser = (Element) (list.item(i));
					return true;// 找到
				}
			}
		} catch (Exception e) {
			//e.printStackTrace();
		}
		return false;
	}

	/**
	 * 用户注册
	 * 
	 * @param name
	 * @param pwd
	 * @return
	 */
	public boolean register(String name, String pwd) {
		try {
			// 创建用户节点
			Element eUser = Main.dom.createElement("user");
			Element eName = Main.dom.createElement("name");
			eName.setTextContent(name);
			Element ePwd = Main.dom.createElement("password");
			ePwd.setTextContent(pwd);
			Element eCon = Main.dom.createElement("contacts");
			// 添加到dom中
			eUser.appendChild(eName);
			eUser.appendChild(ePwd);
			eUser.appendChild(eCon);
			Main.root.appendChild(eUser);
			// 持久化
			return Utils.save(Main.dom);
		} catch (Exception e) {
			//e.printStackTrace();
		}
		return false;
	}

	/**
	 * 找到当前用户的所有联系人
	 * 
	 * @return
	 */
	public List<Contact> getMyContacts() {
		List<Contact> list = new ArrayList<>();
		try {
			if (Main.curUser == null)
				return list;// 防范
			Element eCs = (Element) Main.curUser.getElementsByTagName("contacts").item(0);
			NodeList conList = eCs.getElementsByTagName("contact");// 获取到了当前用户的所有联系人
			for (int i = 0; i < conList.getLength(); i++) {
				// 获取用户名和手机号
				String name = ((Element) conList.item(i)).getElementsByTagName("name").item(0).getTextContent();
				String phone = ((Element) conList.item(i)).getElementsByTagName("phone").item(0).getTextContent();
				list.add(new Contact(name, phone));
			}
		} catch (Exception e) {
			//e.printStackTrace();
		}
		return list;
	}

	/**
	 * 为当前用户添加一个联系人
	 * 
	 * @param contact
	 * @return
	 */
	public boolean addContact(Contact contact) {
		try {
			if (Main.curUser == null)
				return false;
			// 创建联系人节点
			Element eCon = Main.dom.createElement("contact");
			Element eName = Main.dom.createElement("name");
			eName.setTextContent(contact.getName());
			Element ePhone = Main.dom.createElement("phone");
			ePhone.setTextContent(contact.getPhone());
			// 找到当前用户的contacts节点
			Element eCons = (Element) Main.curUser.getElementsByTagName("contacts").item(0);
			// 添加到dom中
			eCon.appendChild(eName);
			eCon.appendChild(ePhone);
			eCons.appendChild(eCon);
			// 持久化
			return Utils.save(Main.dom);
		} catch (Exception e) {
			//e.printStackTrace();
		}
		return false;
	}

	/**
	 * 根据是第几个孩子进行删除联系人
	 * 
	 * @param i
	 * @return
	 */
	public boolean delContact(int i) {
		if (Main.curUser == null)
			return false;
		Element eCons = (Element) (Main.curUser.getElementsByTagName("contacts")).item(0);
		Element eConi = (Element) (eCons.getElementsByTagName("contact")).item(i);
		System.out.println("eConi:"+eConi);
		System.out.println("eConiP:"+eConi.getParentNode());
		eConi.getParentNode().removeChild(eConi);
		try {
			Utils.save(Main.dom);
			return true;
		} catch (TransformerFactoryConfigurationError | TransformerException e) {
			//e.printStackTrace();
		}
		return false;
	}

	/**
	 * 修改当前联系人的指定某个联系人进行修改操作
	 * 
	 * @param contact
	 * @return
	 */
	public boolean modContact(int i, Contact contact) {
		if (Main.curUser == null)
			return false;
		// contacts
		Element eCons = (Element) ((Main.curUser.getElementsByTagName("contacts")).item(0));
		Element eConi = (Element) ((eCons.getElementsByTagName("contact")).item(i));
		eConi.getElementsByTagName("name").item(0).setTextContent(contact.getName());
		eConi.getElementsByTagName("phone").item(0).setTextContent(contact.getPhone());
		try {
			Utils.save(Main.dom);
			return true;
		} catch (TransformerFactoryConfigurationError | TransformerException e) {
			//e.printStackTrace();
		}
		return false;
	}
}

六.工具类

package cn.hncu.xml.contact;

import java.io.File;
import java.util.List;

import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.TransformerFactoryConfigurationError;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.w3c.dom.Document;

public class Utils {
	public static boolean save(Document dom) throws TransformerFactoryConfigurationError, TransformerException {
		Transformer tf = TransformerFactory.newInstance().newTransformer();
		tf.transform(new DOMSource(dom), new StreamResult(new File(Main.fileName)));
		return true;
	}

	/**
	 * 打印当前用户的所有联系人，id从1开始
	 * @param list
	 */
	public static void printContact(List<Contact> list) {
		if (list.size() == 0) {
			System.out.println("没有任何信息");
		} else {
			for(int i = 1;i<=list.size();i++) {
				System.out.println("id: "+i+", "+list.get(i-1));
			}
		}
	}
}