XML学生管理系统_Java版

整个系统的结构是这个样子的。
总共大概三百行代码，供初学者学习。

    <exam>
    <student examid="1111" idcard="5555">
        <name>张三name>
        <location>上海location>
        <grade>9grade>
    student>
    <student>
        <name>李四name>
        <location>大连location>
        <grade>97grade>
    student>
exam>

//StudentDao.java
package cn.itcast.dao;

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

import cn.itcast.domain.Student;
import cn.itcast.utils.XmlUtils;

/**
 * 
        张三
        沈阳
        89
    
 * @author Logan
 *
 */
public class StudentDao {

    public void add(Student student){

        try{
            Document document = XmlUtils.getDocument();
            //student_node  //ctrl+1 rename in file
            Element student_node = document.createElement("student");
            student_node.setAttribute("examid", student.getExamid());
            student_node.setAttribute("idcard", student.getIdcard());

            Element name = document.createElement("name");
            name.setTextContent(student.getName());

            Element location = document.createElement("location");
            location.setTextContent(student.getLocation());

            Element grade = document.createElement("grade");
            grade.setTextContent(student.getGrade()+"");

            student_node.appendChild(name);
            student_node.appendChild(location);
            student_node.appendChild(grade);

            //得到exam节点，并把student挂上去
            document.getElementsByTagName("exam").item(0).appendChild(student_node);

            XmlUtils.write2Xml(document);
        }catch(Exception e){
            throw new RuntimeException(e);
        }

    }

    //删除
    public void delete(String name){
        try{
            Document document = XmlUtils.getDocument();
            NodeList list = document.getElementsByTagName("name");
            for(int i = 0;i
                if(list.item(i).getTextContent().equals(name)){
                    list.item(i).getParentNode().getParentNode().removeChild(list.item(i).getParentNode());
                    XmlUtils.write2Xml(document);
                    return;
                }
            }
            throw new RuntimeException("对不起，您要删除的学生不存在！");//异常也是一种返回值 
        }catch(Exception e){
            throw new RuntimeException(e);
        }
    }

    //查找
    public Student find(String examid){
        try{
            Document document = XmlUtils.getDocument();
            NodeList list = document.getElementsByTagName("student");
            Student student = new Student();
            for(int i = 0;i
                Element student_node = (Element) list.item(i);

                if(student_node.getAttribute("examid").equals(examid)){
                    Student s = new Student();

                    s.setExamid(examid);

                    student.setExamid(student_node.getAttribute("examid"));
                    student.setIdcard(student_node.getAttribute("idcard"));

                    s.setName(student_node.getElementsByTagName("name").item(0).getTextContent());
                    s.setGrade(Double.parseDouble(student_node.getElementsByTagName("grade").item(0).getTextContent()));
                    s.setLocation(student_node.getElementsByTagName("location").item(0).getTextContent());

                    return s;
                }
            }
            return null;
        }catch(Exception e){
            throw new RuntimeException(e);
        }
    }

}

//Student.java
package cn.itcast.domain;

public class Student {

    private String idcard;
    private String examid;
    private String name;
    private String location;
    private Double grade;

    //alt+shift+s

    public String getIdcard() {
        return idcard;
    }
    public void setIdcard(String idcard) {
        this.idcard = idcard;
    }
    public String getExamid() {
        return examid;
    }
    public void setExamid(String examid) {
        this.examid = examid;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getLocation() {
        return location;
    }
    public void setLocation(String location) {
        this.location = location;
    }
    public double getGrade() {
        return grade;
    }
    public void setGrade(double grade) {
        this.grade = grade;
    }
}

//XmlUtils.java
package cn.itcast.utils;

import java.io.File;
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.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

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

public class XmlUtils {
    public static Document getDocument() throws ParserConfigurationException, SAXException, IOException{


        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        DocumentBuilder builder = factory.newDocumentBuilder();
        return builder.parse(new File("src/student.xml"));
    }

    public static void write2Xml(Document document) throws TransformerException{
        TransformerFactory factory = TransformerFactory.newInstance();
        Transformer tf = factory.newTransformer();
        tf.transform(new DOMSource(document), new StreamResult(new File("src/student.xml")));
    }

}

//Main.java
package cn.itcast.view;

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

import cn.itcast.dao.StudentDao;
import cn.itcast.domain.Student;

public class Main {

    public static void main(String[] args) throws IOException {
        // TODO Auto-generated method stub
        System.out.println("添加学生(a)  查找学生(b)  删除学生(c)");
        System.out.print("请输入操作类型:");

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String type = br.readLine();

        if(type.equalsIgnoreCase("a")){
            //添加学生

            try{
                System.out.print("请输入学生姓名：");
                String name = br.readLine();

                System.out.print("请输入学生准考证号：");
                String examid = br.readLine();

                System.out.print("请输入学生身份证号：");
                String idcard = br.readLine();

                System.out.print("请输入学生所在地：");
                String location = br.readLine();

                System.out.print("请输入学生成绩：");
                String grade = br.readLine();

                Student student = new Student();
                student.setExamid(examid);
                student.setGrade(Double.parseDouble(grade));
                student.setIdcard(idcard);
                student.setLocation(location);
                student.setName(name);

                StudentDao dao = new StudentDao();
                dao.add(student);
                System.out.println("恭喜，添加成功！");
            }catch(Exception e){
                System.out.println("对不起，录入失败！");
            }

        }else if(type.equalsIgnoreCase("b")){
            //查找学生

            System.out.print("请输入查找的学生准考证号：");
            String examid = br.readLine();

            StudentDao dao = new StudentDao();
            Student student = dao.find(examid);
            if(student==null){
                System.out.println("对不起，您要查找的学生不存在！");
            }
            else{
                System.out.println("姓名："+student.getName()+",身份证号：" +student.getIdcard()
                +",准考证号:"+student.getExamid()+",地区:"+student.getLocation()+",成绩:"+student.getGrade());
            }
        }else if(type.equalsIgnoreCase("c")){
            //删除学生
            try{
                System.out.print("请输入删除的学生姓名：");
                String name = br.readLine();

                StudentDao dao = new StudentDao();
                dao.delete(name);
                System.out.println("已删除"+name);
                System.out.println("恭喜您，删除成功！");
            }catch(Exception e){
                System.out.println(e.getMessage());
            }

        }else{
            System.out.println("非法字符");
        }

    }
}

该项目也可以使用DOM4j的API实现
下面是部分代码

//StudentDaoWithDOM4j
package cn.itcast.dao;



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

import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;

import cn.itcast.domain.Student;
import cn.itcast.utils.XmlUtilWithDom4j;
public class StudentDaoByDom4j {
    public void add(Student student) throws Exception{
        Document document = XmlUtilWithDom4j.getdocument();
        Element root = document.getRootElement();

        Element student_element = DocumentHelper.createElement("student");
        Element name_element = DocumentHelper.createElement("name");
        Element location_element = DocumentHelper.createElement("location");
        Element grade_element = DocumentHelper.createElement("grade");
        //student_element.addElement("name").setText(student.getName());这种方法也是可以的。
        name_element.setText(student.getName());
        location_element.setText(student.getLocation());
        grade_element.setText(student.getGrade()+"");
        student_element.addAttribute("examid", student.getExamid());
        student_element.addAttribute("idcard", student.getIdcard());
        student_element.add(name_element);
        student_element.add(location_element);
        student_element.add(grade_element);

        root.add(student_element);
        XmlUtilWithDom4j.write2xml(document);
    }
    public void delete(String name) throws Exception{
        Document document = XmlUtilWithDom4j.getdocument();
        Element root = document.getRootElement();

        List list = document.getRootElement().elements("student");
        for(int i = 0;i
            Element student_element = (Element) list.get(i);
            if(student_element.element("name").getText().equals(name)){
                root.remove(student_element);
            }
        }


        XmlUtilWithDom4j.write2xml(document);


    }
    public Student find(String examid) throws Exception{
        Document document = XmlUtilWithDom4j.getdocument();
        Element root = document.getRootElement();

        Student student = new Student();
        List list = document.getRootElement().elements("student");
        for(int i = 0;i
            Element student_element = (Element) list.get(i);
            if(student_element.attributeValue("examid").equals(examid)){
                student.setExamid(examid);
                student.setIdcard(student_element.attributeValue("idcard"));
                student.setGrade(Double.parseDouble(student_element.element("grade").getText()));
                student.setLocation(student_element.element("location").getText());
                student.setName(student_element.element("name").getText());
                return student;
            }
        }
        return null;
    }

}

//XmlUtilWithDOM4j
package cn.itcast.utils;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.UnsupportedEncodingException;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;



public class XmlUtilWithDom4j {

    public static Document getdocument() throws Exception{
        SAXReader reader = new SAXReader();
        Document document = reader.read(new File("src/student.xml"));
        return document;

    }

    public static void write2xml(Document document) throws Exception, FileNotFoundException{
        OutputFormat format = OutputFormat.createPrettyPrint();
        format.setEncoding("UTF-8");

        XMLWriter writer = new XMLWriter(new FileOutputStream("src/student.xml"));
        writer.write(document);
        writer.close();
    }

}