实体类

public class User {    private String id;    private String username;    private String password;    public User(){}    public String getId() {        return id;    }    public void setId(String id) {        this.id = id;    }    public String getUsername() {        return username;    }    public void setUsername(String username) {        this.username = username;    }    public String getPassword() {        return password;    }    public void setPassword(String password) {        this.password = password;    }}

表现层：

//输入输出public class LoginUI {    public User input()    {        User user = new User();        Scanner scanner = new Scanner(System.in);        System.out.print("用户名：");        String username = scanner.nextLine();        System.out.print("密码：");        String password = scanner.nextLine();        user.setUsername(username);        user.setPassword(password);        return user;    }    public void output(boolean flag)    {        if(flag)        {            System.out.println("登陆成功");        }else        {            System.out.println("登陆失败");        }    }}

业务层：

import java.io.File;import org.dom4j.Document;import org.dom4j.Element;import org.dom4j.io.SAXReader;import org.junit.Test;public class LoginBusiness {    @Test    public void logingtet() throws Exception    {        LoginUI loginUI = new LoginUI();        LoginBusiness lognBusiness = new LoginBusiness();        User user = loginUI.input();        boolean flag = lognBusiness.check(user);        loginUI.output(flag);    }    //判断    public boolean check(User user) throws Exception    {        boolean flag = false;        SAXReader saxReader = new SAXReader();        Document document = saxReader.read(new File("src/day2/domx/users.xml"));        String xpath = "http://user[@username='"+user.getUsername()+"' and @password='"+user.getPassword()+"']";        Element element = (Element) document.selectSingleNode(xpath);        if(element !=null)        {            flag = true;        }        return flag;        }}

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

-<root>

<user password="123456" username="liwen" id="id001"/>

<user password="23456" username="python" id="id002"/>

</root>