java(12)--小应用-基于xml的简单考试查询系统

需求：
考试系统需求文档
1、 以如的exam.xml文件为例

package zgq.UI;

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

import zgq.beans.Student;
import zgq.dao.StudentDao;
import zgq.exception.StudentNotExistException;

public class Main {
    public static void main(String[] args) {
        try {
            System.out.println("添加用户：（a） 删除用户：（b） 查询成绩（c");
            System.out.print("请输入操作类型：");

            // 获取用户输入
            BufferedReader bufr = new BufferedReader(new InputStreamReader(
                    System.in));
            String in = bufr.readLine();

            if ("a".equals(in)) {
                System.out.print("请输入学生姓名：");
                String name = bufr.readLine();

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

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

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

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

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

                StudentDao dao = new StudentDao();
                dao.add(s);

                System.out.println("添加成功！！");
            }

            else if ("b".equals(in)) {
                System.out.print("请输入要删除的学生的姓名：");
                String name  = bufr.readLine();
                try{
                    StudentDao dao = new StudentDao();
                    dao.delete(name);
                    System.out.println("删除成功！！");
                }catch (StudentNotExistException e) {
                    System.out.println("您要删除的用户不存在！！");
                }
            }

            else if ("c".equals(in)) {
                System.out.print("请输入要删除的学生的准考证号：");
                String examid  = bufr.readLine();

                StudentDao studentDao=new StudentDao();
                Student student= studentDao.find(examid);
                if(student!=null){
                    System.out.println("Examid:"+student.getExamid());
                    System.out.println("Idcard:"+student.getIdcard());
                    System.out.println("Name:"+student.getName());
                    System.out.println("Location:"+student.getLocation());
                    System.out.println("Grade:"+student.getGrade());
                }
                else {
                    System.out.println("您输入的准考证号有误，未能查到相关信息");
                }
            }
            else {
                System.out.println("您输入的有误！运行截止。");
                return;
            }

        } catch (IOException e) {
            e.printStackTrace();
            System.out.println("对不起，出错了！！");
        }

    }
}

utils包

package zgq.utils;

import java.io.FileOutputStream;

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

import org.w3c.dom.Document;

public class XmlUtils {

    //在工具类中，尽量将字段和方法定义为静态的
    private static String filename="src/exam.xml";

    //获取Document文档
    public static Document getDocument() throws Exception{
        DocumentBuilderFactory factory=DocumentBuilderFactory.newInstance();
        DocumentBuilder builder= factory.newDocumentBuilder();
        Document document=builder.parse(filename);
        return document;
    }

    //写入Document内容
    public static void writeToXml(Document document) throws Exception{
        TransformerFactory factory=TransformerFactory.newInstance();
        Transformer former= factory.newTransformer();
        former.transform(new DOMSource(document), new StreamResult(new FileOutputStream(filename)));
    }
}

bean包

package zgq.beans;

public class Student {

    private String idcard;
    private String examid;
    private String name;
    private String location;
    private double grade;
    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;
    }
}

DAO包

package zgq.dao;

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

import zgq.beans.Student;
import zgq.exception.StudentNotExistException;
import zgq.utils.XmlUtils;

public class StudentDao {

    //添加信息
    public void add(Student s){
        try {
            //获取exam.xml文档dom树
            Document document=XmlUtils.getDocument();

            //创建出封装学生信息的标签<student examid="222" idcard="111"></student>
            Element student_tag=document.createElement("student");
            student_tag.setAttribute("examid",s.getExamid());
            student_tag.setAttribute("idcard", s.getIdcard());

            //创建用于封装学生姓名的标签
            Element student_name=document.createElement("name");
            student_name.setTextContent(s.getName());

            //创建用于封装学生所在地的标签
            Element student_location=document.createElement("location");
            student_location.setTextContent(s.getLocation());

            //创建用于封装学生成绩的标签
            Element student_grade=document.createElement("grade");
            student_grade.setTextContent(s.getGrade()+"");

            //将姓名所在地和成绩挂载到student_tag标签上
            student_tag.appendChild(student_name);
            student_tag.appendChild(student_location);
            student_tag.appendChild(student_grade);

            //将新得到的文件内容挂载到exam节点上
            document.getElementsByTagName("exam").item(0).appendChild(student_tag);

            //更新xml文件
            XmlUtils.writeToXml(document);

        } catch (Exception e) {
            throw new RuntimeException(e); //unchecked exception(运行时异常)
                                             //checked exception(编译时异常)
        }
    }

    //查找信息
    public Student find(String examid){
        try {
            Document document=XmlUtils.getDocument();

            //获取student标签集合
            NodeList students=document.getElementsByTagName("student");

            //循环获取 查看student的属性examid
            for(int i=0;i<students.getLength();i++){
                Element student_tag=(Element) students.item(i);
                if(student_tag.getAttribute("examid").equals(examid)){ //找到匹配学生
                    Student s=new Student();
                    s.setExamid(examid);
                    s.setIdcard(student_tag.getAttribute("idcard"));
                    s.setName(student_tag.getElementsByTagName("name").item(0).getTextContent());
                    s.setLocation(student_tag.getElementsByTagName("location").item(0).getTextContent());
                    s.setGrade(Double.parseDouble(student_tag.getElementsByTagName("grade").item(0).getTextContent()));
                    return s;
                }
            }
            return null;
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }


    public void delete(String name) throws StudentNotExistException{  //根据姓名进行删除操作
        Document document;
        try {
            document = XmlUtils.getDocument();
            NodeList students=document.getElementsByTagName("name"); //通过name获取学生集合
            for(int i=0;i<students.getLength();i++){
                if(students.item(i).getTextContent().equals(name)){
                    //得到指定节点 进行删除操作
                    students.item(i).getParentNode().getParentNode().removeChild(students.item(i).getParentNode());

                    //重新写入xml文件
                    XmlUtils.writeToXml(document);
                    return;
                }
            }
            throw new StudentNotExistException("删除节点不存在");

        }catch(StudentNotExistException e){
            throw e;
        } catch (Exception e) {
            throw new RuntimeException(e);
        }

    }
}

异常包

package zgq.exception;

public class StudentNotExistException extends Exception {
    //自定义类
    public StudentNotExistException() {
        // TODO 自动生成的构造函数存根
    }

    public StudentNotExistException(String message) {
        super(message);
        // TODO 自动生成的构造函数存根
    }

    public StudentNotExistException(Throwable cause) {
        super(cause);
        // TODO 自动生成的构造函数存根
    }

    public StudentNotExistException(String message, Throwable cause) {
        super(message, cause);
        // TODO 自动生成的构造函数存根
    }

// public StudentNotExistException(String message, Throwable cause,
// boolean enableSuppression, boolean writableStackTrace) {
// super(message, cause, enableSuppression, writableStackTrace);
// // TODO 自动生成的构造函数存根
// }

}

测试包：

package junit.test;

import org.junit.Test;

import zgq.beans.Student;
import zgq.dao.StudentDao;
import zgq.exception.StudentNotExistException;

public class StudentDaoTest {

    @Test
    public void testAdd(){
        StudentDao studentDao=new StudentDao();
        Student student=new Student();
        student.setExamid("123");
        student.setIdcard("321");
        student.setName("王五");
        student.setLocation("北京");
        student.setGrade(97);
        studentDao.add(student);
    }

    @Test
    public void testFind(){
        StudentDao studentDao=new StudentDao();
        Student student= studentDao.find("123");
        System.out.println("Examid:"+student.getExamid());
        System.out.println("Idcard:"+student.getIdcard());
        System.out.println("Name:"+student.getName());
        System.out.println("Location:"+student.getLocation());
        System.out.println("Grade:"+student.getGrade());
    }

    @Test
    public void testDelete() throws StudentNotExistException {
        StudentDao studentDao=new StudentDao();
        studentDao.delete("王五");
    }
}

项目地址：https://github.com/Mrzhoug/exam_base_xml.git