1.界面介绍
2.系统结构介绍
我把各个包介绍一下
1.exam.xml文件就是用来模拟数据库的，代码在后面贴出来
2.dao层时操作数据包
3.utils是工具类包
4.bean是数据封装类包
5.exception是自定义异常类包
6.junit测试包
7.ui用户界面包
3.详细代码
1.exam.xml
1 <?xml version="1.0" encoding="UTF-8" standalone="no"?><exam> 2 <student examid="456" idcard="123"> 3 <name>a</name> 4 <location>b</location> 5 <grade>22</grade> 6 </student> 7 8 <student examid="000" idcard="789"> 9 <name>c</name> 10 <location>d</location> 11 <grade>20</grade> 12 </student> 13 14 15 </exam>
2.XmlUtils.java
1 package utils;
2
3 import java.io.FileOutputStream;
4
5 import javax.xml.parsers.DocumentBuilder;
6 import javax.xml.parsers.DocumentBuilderFactory;
7 import javax.xml.transform.Transformer;
8 import javax.xml.transform.TransformerFactory;
9 import javax.xml.transform.dom.DOMSource;
10 import javax.xml.transform.stream.StreamResult;
11
12 import org.w3c.dom.Document;
13
14 //工具类的所有方法都是静态的（约定俗成）
15 public class XmlUtils {
16
17 private static String filename = "src/exam.xml";
18
19 public static Document getDocument() throws Exception{
20
21 DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
22 DocumentBuilder builder = factory.newDocumentBuilder();
23 return builder.parse(filename);
24
25 }
26
27 public static void write2Xml(Document document) throws Exception{
28
29 TransformerFactory factory = TransformerFactory.newInstance();
30 Transformer tf = factory.newTransformer();
31 tf.transform(new DOMSource(document), new StreamResult(new FileOutputStream(filename)));
32
33 }
34
35 }
getDocument()方法用来获取标签对象
write2Xml(Document document)方法用来更新xml文件
3.StudentDao.java
1 package dao;
2
3 import org.w3c.dom.Document;
4 import org.w3c.dom.Element;
5 import org.w3c.dom.NodeList;
6
7 import bean.Student;
8 import exception.StudentNotExistException;
9 import utils.XmlUtils;
10
11 public class StudentDao {
12
13 public void add(Student s){
14
15 try {
16 Document document = XmlUtils.getDocument();
17
18 //创建出封装学生的标签
19 Element student_tag = document.createElement("student");
20 student_tag.setAttribute("idcard", s.getIdcard());
21 student_tag.setAttribute("examid", s.getExamid());
22
23 //创建用于封装学生姓名，所在地和成绩的标签
24 Element name = document.createElement("name");
25 Element location = document.createElement("location");
26 Element grade = document.createElement("grade");
27 name.setTextContent(s.getName());
28 location.setTextContent(s.getIdcard());
29 grade.setTextContent(s.getGrade()+"");
30
31 //设置标签之间的关系
32 student_tag.appendChild(name);
33 student_tag.appendChild(location);
34 student_tag.appendChild(grade);
35
36 //把封装信息的学生标签，要挂在文档上面
37 document.getElementsByTagName("exam").item(0).appendChild(student_tag);
38
39 //更新内存
40 XmlUtils.write2Xml(document);
41
42 } catch (Exception e) {
43 //把异常进行转型，把编译时异常转化成运行时异常
44 throw new RuntimeException(e);
45 }
46
47
48 }
49
50 public Student find(String examid){
51
52 try {
53 Document document = XmlUtils.getDocument();
54 NodeList list = document.getElementsByTagName("student");
55 for(int i=0; i<list.getLength(); i++){
56 Element student_tag = (Element) list.item(i);
57 if(student_tag.getAttribute("examid").equals(examid)){
58 //找到与examid相对应的学生，new出一个student对象封装这个学生的信息返回
59 Student s = new Student();
60 s.setExamid(examid);
61 s.setIdcard(student_tag.getAttribute("idcard"));
62 s.setName(student_tag.getElementsByTagName("name").item(0).getTextContent());
63 s.setLocation(student_tag.getElementsByTagName("location").item(0).getTextContent());
64 s.setGrade(Double.parseDouble(student_tag.getElementsByTagName("grade").item(0).getTextContent()));
65 return s;
66 }
67 }
68 return null;
69 } catch (Exception e) {
70 // TODO Auto-generated catch block
71 throw new RuntimeException(e);
72 }
73 }
74
75 public void delete(String name) throws StudentNotExistException{
76
77 try {
78 Document document = XmlUtils.getDocument();
79 NodeList list = document.getElementsByTagName("name");
80 for(int i=0; i<list.getLength(); i++){
81 if(list.item(i).getTextContent().equals(name)){
82 list.item(i).getParentNode().getParentNode().removeChild(list.item(i).getParentNode());
83 XmlUtils.write2Xml(document);
84 return;
85 }
86 }
87 throw new StudentNotExistException(name + "不存在！");
88 }catch(StudentNotExistException e){
89 throw e;
90 }catch (Exception e) {
91 // TODO Auto-generated catch block
92 throw new RuntimeException();
93 }
94
95 }
96
97 }
4.student.java
1 package bean;
2
3 public class Student {
4
5 @Override
6 public String toString() {
7 return "Student [name=" + name + ", location=" + location + ", grade=" + grade + ", idcard=" + idcard
8 + ", examid=" + examid + "]";
9 }
10 private String name;
11 private String location;
12 private double grade;
13 private String idcard;
14 private String examid;
15
16 public String getName() {
17 return name;
18 }
19 public void setName(String name) {
20 this.name = name;
21 }
22 public String getLocation() {
23 return location;
24 }
25 public void setLocation(String location) {
26 this.location = location;
27 }
28 public double getGrade() {
29 return grade;
30 }
31 public void setGrade(double grade) {
32 this.grade = grade;
33 }
34 public String getIdcard() {
35 return idcard;
36 }
37 public void setIdcard(String idcard) {
38 this.idcard = idcard;
39 }
40 public String getExamid() {
41 return examid;
42 }
43 public void setExamid(String examid) {
44 this.examid = examid;
45 }
46
47 }
5.StudentNotExistException.java
1 package exception;
2
3 public class StudentNotExistException extends Exception {
4
5 public StudentNotExistException() {
6 // TODO Auto-generated constructor stub
7 }
8
9 public StudentNotExistException(String message) {
10 super(message);
11 // TODO Auto-generated constructor stub
12 }
13
14 public StudentNotExistException(Throwable cause) {
15 super(cause);
16 // TODO Auto-generated constructor stub
17 }
18
19 public StudentNotExistException(String message, Throwable cause) {
20 super(message, cause);
21 // TODO Auto-generated constructor stub
22 }
23
24 public StudentNotExistException(String message, Throwable cause, boolean enableSuppression,
25 boolean writableStackTrace) {
26 super(message, cause, enableSuppression, writableStackTrace);
27 // TODO Auto-generated constructor stub
28 }
29
30 }
6.Main.java
1 package ui;
2
3 import java.io.BufferedReader;
4 import java.io.InputStreamReader;
5
6 import bean.Student;
7 import dao.StudentDao;
8 import exception.StudentNotExistException;
9
10 public class Main {
11
12 public static void main(String[] args) {
13 // TODO Auto-generated method stub
14 try{
15 System.out.println("添加学生：（a） 删除学生（b） 查找学生（c） 退出（e）");
16 System.out.print("请输入操作类型：");
17 BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
18 String type = br.readLine();
19 //switch不能用String
20 if("a".equals(type)){
21
22 System.out.println("请输入学生姓名：");
23 String name = br.readLine();
24
25 System.out.println("请输入学生准考证号：");
26 String examid = br.readLine();
27
28 System.out.println("请输入学生身份证号：");
29 String idcard = br.readLine();
30
31 System.out.println("请输入学生所在地：");
32 String location = br.readLine();
33
34 System.out.println("请输入学生成绩：");
35 String grade = br.readLine();
36
37 Student s = new Student();
38 s.setExamid(examid);
39 s.setGrade(Double.parseDouble(grade));
40 s.setIdcard(idcard);
41 s.setName(name);
42 s.setLocation(location);
43
44 StudentDao dao = new StudentDao();
45 dao.add(s);
46 System.out.println("添加成功");
47
48 }else if("b".equals(type)){
49
50 System.out.print("请输入要删除学生的姓名：");
51 String name = br.readLine();
52 try{
53 StudentDao dao = new StudentDao();
54 dao.delete(name);
55 System.out.println("删除成功！");
56 }catch(StudentNotExistException e){
57 System.out.println("此学生不存在！");
58 }
59
60 }else if("c".equals(type)){
61
62 System.out.println("请输入要查找用户的准考证号");
63 String examid = br.readLine();
64 StudentDao dao = new StudentDao();
65 Student s = dao.find(examid);
66 System.out.println(s);
67
68 }else if("e".equals(type)){
69
70 System.out.println("退出成功！");
71 return;
72
73 }else{
74 System.out.println("不支持你的操作！");
75 }
76 }catch(Exception e){
77 e.printStackTrace();
78 System.out.println("对不起，出错误了");
79 }
80 }
81
82 }
原文地址：https://www.cnblogs.com/Vamps0911/p/10804546.html
时间： 2024-10-10 17:54:28