xml版本学生管理系统

一： 需求描述

学生成绩管理系统，使用xml存储学生信息，可以对学生信息进行增、删、删除操作。

主要目的：练习操作xml元素的增删改查

二：代码结构

1：xml存储数据如下

exam.xml

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<students>
    <student>
        <name sid="111">李四</name>
        <age>23</age>
        <gender>男</gender>
    </student>
    <student>
        <name sid="222">张三</name>
        <age>21</age>
        <gender>女</gender>
    </student>
</students>

2：Student类封装学生信息

/**
 * 
 */
package com.hlcui.entity;

/**
 * @author Administrator
 * 
 */
public class Student {
    private int id;
    private String name;
    private int age;
    private String gender;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

}

3:数据访问层，封装操作xml数据的方法

/**
 * 
 */
package com.hlcui.dao;

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

import com.hlcui.entity.Student;
import com.hlcui.exception.NameNotFoundException;
import com.hlcui.utils.StudentUtils;

/**
 * @author Administrator
 * 
 */
public class StudentDAO {
    // 添加学生信息
    public void add(Student stu) {
        try {
            Document doc = StudentUtils.getDocument();
            Element student = doc.createElement("student");
            student.setAttribute("id", stu.getId() + ""); // 给学生元素添加属性

            // 分别创建姓名、年龄、性别节点
            Element name = doc.createElement("name");
            name.setTextContent(stu.getName());
            Element age = doc.createElement("age");
            age.setTextContent(stu.getAge() + "");
            Element gender = doc.createElement("gender");
            gender.setTextContent(stu.getGender());

            // 将姓名、年龄、性别节点添加到学生节点上
            student.appendChild(name);
            student.appendChild(age);
            student.appendChild(gender);

            // 在将student节点添加到students节点上
            doc.getElementsByTagName("students").item(0).appendChild(student);
            StudentUtils.write2XML(doc);
            System.out.println("添加成功！");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    // 根据学生姓名查询学生信息
    public Student find(String name) throws NameNotFoundException {
        try {
            Document doc = StudentUtils.getDocument();
            NodeList list = doc.getElementsByTagName("student");
            for (int i = 0; i < list.getLength(); i++) {
                Element ele = (Element) list.item(i);
                if (name.equals((ele.getElementsByTagName("name")).item(0)
                        .getTextContent())) {
                    Student stu = new Student();
                    stu.setId(Integer.parseInt(ele.getAttribute("id")));
                    stu.setName(name);
                    stu.setAge(Integer.parseInt((ele
                            .getElementsByTagName("age")).item(0)
                            .getTextContent()));
                    stu.setGender(ele.getElementsByTagName("gender").item(0)
                            .getTextContent());
                    return stu;
                }
            }
            throw new NameNotFoundException(name + "不存在！！！");
        } catch (NameNotFoundException e) {
            throw e;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    // 根据id删除学生信息
    public boolean delete(int id) {
        try {
            Document doc = StudentUtils.getDocument();
            NodeList list = doc.getElementsByTagName("student");
            for (int i = 0; i < list.getLength(); i++) {
                Element ele = (Element) list.item(i);
                if (String.valueOf(id).equals(ele.getAttribute("id"))) {
                    ele.getParentNode().removeChild(ele);
                    StudentUtils.write2XML(doc);
                    return true;
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return false;
    }
}

4：自定义异常类，封装异常

/**
 * 
 */
package com.hlcui.exception;

/**
 * @author Administrator
 *
 */
public class NameNotFoundException extends Exception {

    /**
     * 
     */
    private static final long serialVersionUID = 1L;

    /**
     * 
     */
    public NameNotFoundException() {
    }

    /**
     * @param message
     */
    public NameNotFoundException(String message) {
        super(message);
    }

    /**
     * @param cause
     */
    public NameNotFoundException(Throwable cause) {
        super(cause);
    }

    /**
     * @param message
     * @param cause
     */
    public NameNotFoundException(String message, Throwable cause) {
        super(message, cause);
    }

}

5：junit框架测试DAO方法

/**
 * 
 */
package com.hlcui.test;

import org.junit.Test;

import com.hlcui.dao.StudentDAO;
import com.hlcui.entity.Student;
import com.hlcui.exception.NameNotFoundException;

/**
 * @author Administrator
 * 
 */
public class TestStudentDAO {
    private StudentDAO dao = new StudentDAO();

    @Test
    public void testAdd() {
        Student stu = new Student();
        stu.setId(333);
        stu.setName("王二");
        stu.setAge(27);
        stu.setGender("男");
        dao.add(stu);
    }

    @Test
    public void testFind() throws NameNotFoundException {
        String name = "王二";
        Student stu = dao.find(name);
        System.out.println("学号：" + stu.getId() + "
姓名：" + stu.getName()
                + "
年龄：" + stu.getAge() + "
性别：" + stu.getGender());

    }

    @Test
    public void testDelete() {
        int id = 333;
        boolean flag = dao.delete(id);
        System.out.println(flag ? "删除成功！！" : "删除失败！！");
    }
}

6:封装操作dom文件功能方法

/**
 * 
 */
package com.hlcui.utils;

import java.io.FileOutputStream;
import java.io.IOException;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.w3c.dom.Document;

/**
 * @author Administrator
 * 
 */
public class StudentUtils {

    /* 获取Document对象* */
    public static Document getDocument() throws Exception {
        DocumentBuilderFactory sfb = DocumentBuilderFactory.newInstance();
        DocumentBuilder db = sfb.newDocumentBuilder();
        Document doc = db.parse("xml/exam.xml");
        return doc;
    }

    /* 将内存中的内容写到硬盘* */
    public static void write2XML(Document doc) throws Exception {
        TransformerFactory factory = TransformerFactory.newInstance();
        Transformer tf = factory.newTransformer();
        tf.transform(new DOMSource(doc), new StreamResult(new FileOutputStream(
                "xml/exam.xml")));
    }
}

7：用户交互界面

/**
 * 
 */
package com.hlcui.ui;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

import com.hlcui.dao.StudentDAO;
import com.hlcui.entity.Student;
import com.hlcui.exception.NameNotFoundException;

/**
 * @author Administrator 用户交互界面
 */
public class Main {

    public static StudentDAO dao = new StudentDAO();

    /**
     * 
     * @param args
     */
    public static void main(String[] args) {

        System.out.println("请选择操作模式：a:添加用户    b：查找用户    c：删除用户   exit:退出系统");
        BufferedReader br = null;
        try {
            while (true) {
                br = new BufferedReader(new InputStreamReader(System.in));
                String type = br.readLine();
                if ("a".equals(type)) {

                    // 录入数据
                    System.out.println("请输入学号：");
                    int id = Integer.parseInt(br.readLine());
                    System.out.println("请输入姓名：");
                    String name = br.readLine();
                    System.out.println("请输入年龄：");
                    int age = Integer.parseInt(br.readLine());
                    System.out.println("请输入性别：");
                    String gender = br.readLine();
                    // 封装数据
                    Student stu = new Student();
                    stu.setId(id);
                    stu.setName(name);
                    stu.setAge(age);
                    stu.setGender(gender);

                    // 插入数据
                    dao.add(stu);
                } else if ("b".equals(type)) {
                    System.out.println("请输入姓名：");
                    String name = br.readLine();
                    try {
                        Student stu = dao.find(name);
                        System.out.println("***********学生信息如下***********");
                        System.out.println("学号：" + stu.getId() + "
姓名："
                                + stu.getName() + "
年龄：" + stu.getAge()
                                + "
性别：" + stu.getGender());
                    } catch (NameNotFoundException e) {
                        System.out.println(e.getMessage());
                    }
                } else if ("c".equals(type)) {
                    System.out.println("请输入学号：");
                    int id = Integer.parseInt(br.readLine());
                    boolean flag = dao.delete(id);
                    if (flag) {
                        System.out.println("删除成功！");
                    } else {
                        System.out.println("删除失败!");
                    }
                } else if ("exit".equals(type.toLowerCase())) {
                    System.out.println("系统正在退出...");
                    try {
                        Thread.sleep(3000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    break;
                } else {
                    System.out.println("您的操作暂不支持，请重新输入:");
                }
            }

        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (null != br) {
                try {
                    br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

代码均已经验证正确！