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() + "\n姓名：" + stu.getName()
                 + "\n年龄：" + stu.getAge() + "\n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() + "\n姓名："
                                 + stu.getName() + "\n年龄：" + stu.getAge()
                                 + "\n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！