github地址：https://github.com/qscqesze/StudentManager
简单描述一下：
UI层面用于接受用户的处理信息，然后移交给StudentDao去处理数据。
其中StudentDao通过修改Xml充当的数据库，来反馈数据。
StudentDomain是用来定义数据类型，Studentutils是处理数据时候封装的工具类型。
写了个额外的异常，Exception。
我也是参考着教程写的：《30天轻松掌握JavaWeb视频》 方立勋，网易云课堂里面有这个课程。
然后这个代码就结束了。
具体代码如下：
exam.xml //数据库文件
<?xml version="1.0" encoding="UTF-8" standalone="no"?><exam>
<student examid="222" idcard="111">
<name>张三</name>
<location>沈阳</location>
<grade>89</grade>
</student>
<student examid="444" idcard="333">
<name>李四</name>
<location>大连</location>
<grade>97</grade>
</student>
</exam>
StudentDaoTest.java //测试文件
package junit.test;
import org.junit.Test;
import en.itcast.dao.StudentDao;
import en.itcast.domain.Student;
import en.itcast.exception.StudentNotExistException;
public class StudentDaoTest {
@Test
public void testAdd(){
StudentDao dao = new StudentDao();
Student s = new Student();
s.setExamid("121");
s.setGrade(89);
s.setIdcard("121");
s.setLocation("北京");
s.setName("aa");
dao.add(s);
}
@Test
public void testFind(){
StudentDao dao = new StudentDao();
dao.find("222");
}
@Test
public void testdelete() throws StudentNotExistException{
StudentDao dao = new StudentDao();
dao.delete("aa");
}
}
XmlUtils.java //工具类文件
package en.itcast.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 {
// 工具类约定俗成为静态类
private static String filename = "src/exam.xml";
public static Document getDocument() throws Exception {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
return builder.parse(filename);
}
// 编译异常就是垃圾
public static void write2Xml(Document document) throws Exception {
TransformerFactory factory = TransformerFactory.newInstance();
Transformer tf = factory.newTransformer();
tf.transform(new DOMSource(document),new StreamResult(new FileOutputStream(filename)));
}
}
Main.java //主程序，ui界面的
package en.itcast.UI;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import en.itcast.dao.StudentDao;
import en.itcast.domain.Student;
import en.itcast.exception.StudentNotExistException;
public class Main {
public static void main(String[] args) {
System.out.println("添加用户(a) 删除用户(b) 查找用户(c)");
System.out.print("请输入操作类型:");
BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
try {
String type = bf.readLine();
if ("a".equals(type)) {
System.out.print("请输入学生姓名:");
String name = bf.readLine();
System.out.print("请输入学生准考证号:");
String examid = bf.readLine();
System.out.print("请输入学生所在地:");
String location = bf.readLine();
System.out.print("请输入学生身份证:");
String idcard = bf.readLine();
System.out.print("请输入学生成绩:");
String grade = bf.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(type)) {
System.out.print("请输入要删除的学生姓名:");
String name = bf.readLine();
try {
StudentDao dao = new StudentDao();
dao.delete(name);
System.out.println("删除成功.");
} catch (StudentNotExistException e) {
System.out.println("你删除的用户不存在.");
}
} else if ("c".equals(type)) {
System.out.print("请输入你要查询的准考证id:");
String examid = bf.readLine();
StudentDao dao = new StudentDao();
Student find_student = dao.find(examid);
if(find_student.equals(null)){
System.out.println("对不起，找不到该学生.");
}else{
System.out.println("该学生的姓名是:"+find_student.getName());
}
} else {
System.out.println("不支持你的操作");
}
} catch (IOException e) {
e.printStackTrace();
;
System.out.println("sorry");
}
}
}
StudentNotExistException.java //自定义异常，处理删除的时候不存在用
package en.itcast.exception;
public class StudentNotExistException extends Exception {
public StudentNotExistException() {
// TODO Auto-generated constructor stub
}
public StudentNotExistException(String message) {
super(message);
// TODO Auto-generated constructor stub
}
public StudentNotExistException(Throwable cause) {
super(cause);
// TODO Auto-generated constructor stub
}
public StudentNotExistException(String message, Throwable cause) {
super(message, cause);
// TODO Auto-generated constructor stub
}
public StudentNotExistException(String message, Throwable cause, boolean enableSuppression,
boolean writableStackTrace) {
super(message, cause, enableSuppression, writableStackTrace);
// TODO Auto-generated constructor stub
}
}
Student.java //封装Student的数据类型
package en.itcast.domain;
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;
}
}
StudentDao.java //程序处理
package en.itcast.dao;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;
import en.itcast.domain.Student;
import en.itcast.exception.StudentNotExistException;
import en.itcast.utils.XmlUtils;
public class StudentDao {
public void add(Student s) {
try {
Document document = XmlUtils.getDocument();
// 创建出封装学生信息的标签
Element student_tag = document.createElement("student");
student_tag.setAttribute("idcard", s.getIdcard());
student_tag.setAttribute("examid", s.getExamid());
// 创建用于封装学生其他信息的标签
Element name = document.createElement("name");
Element location = document.createElement("location");
Element grade = document.createElement("grade");
name.setTextContent(s.getName());
location.setTextContent(s.getLocation());
grade.setTextContent(s.getGrade() + "");
student_tag.appendChild(name);
student_tag.appendChild(location);
student_tag.appendChild(grade);
// 把封装的信息挂在文档上
document.getElementsByTagName("exam").item(0).appendChild(student_tag);
XmlUtils.write2Xml(document);
} catch (Exception e) {
throw new RuntimeException(e);
}
}
public Student find(String examid) {
try {
Document document = XmlUtils.getDocument();
NodeList list = document.getElementsByTagName("student");
for (int i = 0; i < list.getLength(); i++) {
Element student_tag = (Element) list.item(i);
if (student_tag.getAttribute("examid").equals(examid)) {
// 找到匹配的学生了,new一个student对象
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 {
try {
Document document = XmlUtils.getDocument();
NodeList list = document.getElementsByTagName("name");
for (int i = 0; i < list.getLength(); i++) {
if (list.item(i).getTextContent().equals(name)) {
list.item(i).getParentNode().getParentNode().removeChild(list.item(i).getParentNode());
XmlUtils.write2Xml(document);
return;
}
}
throw new StudentNotExistException(name + "不存在");
} catch (StudentNotExistException e) {
throw e;
} catch (Exception e) {
throw new RuntimeException(e);
}
}
}