DOM解析XML文件例項之學生管理系統
阿新 • • 發佈：2019-01-07
/**
*@ author StormMaybin
*@ date 2016-10-06
*/生命不息，奮鬥不止！
需求分析：
用XML文件來儲存學生資訊，
通過對XML文件的增刪改，來實現管理學生資訊的功能。
主體結構
學生類
package com.stormma.domain;
public class Student
{
private String idCard;
private String examId;
private String name;
private String location;
private XML工具類
package com.stormma.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;
/**
* @author StormMaybin writeToXML()方法 getDocument()方法
*/
public class XMLUtils
{
private static final String fileName = "src/exam.xml";
public static Document getDocument() throws Exception
{
// 獲得工廠例項
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
// 獲得解析器
DocumentBuilder builder = factory.newDocumentBuilder();
// 解析文件
return builder.parse(fileName);
}
public static void writeToXML(Document document) throws Exception
{
Transformer tf = TransformerFactory.newInstance().newTransformer();
tf.transform(new DOMSource(document), new StreamResult(
new FileOutputStream(fileName)));
}
}
操作XML文件的StudentDao類
package com.stormma.dao;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;
import com.stormma.domain.Student;
import com.stormma.exception.StudentNotExistException;
import com.stormma.utils.XMLUtils;
/**
* 用來和資料庫（XML檔案）互動
* @author StormMaybin
* 操作：新增學生、查詢學生、刪除學生
*/
public class StudentDao
{
public void add (Student s)
{
try
{
//得到對應XML文件物件
Document document = XMLUtils.getDocument();
//建立學生標籤
Element student_tag = document.createElement("student");
//設定student標籤的屬性
student_tag.setAttribute("idCard", s.getIdCard());
student_tag.setAttribute("examId", s.getExamId());
//建立student標籤的子標籤
Element name = document.createElement("name");
Element location = document.createElement("location");
Element grade = document.createElement("grade");
//設定標籤內容
name.setTextContent(s.getName());
location.setTextContent(s.getLocation());
grade.setTextContent(s.getGrade()+"");
//建立標籤關係
student_tag.appendChild(name);
student_tag.appendChild(location);
student_tag.appendChild(grade);
//得到student父節點
Element exam = (Element) document.getElementsByTagName("exam").item(0);
exam.appendChild(student_tag);
//更新文件內容
XMLUtils.writeToXML(document);
}
catch (Exception e)
{
// TODO Auto-generated catch block
//異常轉型
throw new RuntimeException(e);
}
}
public Student find (String examId)
{
try
{
//得到對應XML文件物件
Document document = XMLUtils.getDocument();
//得到學生標籤集合
NodeList sList = document.getElementsByTagName("student");
for (int i = 0; i < sList.getLength(); i++)
{
Element student = (Element) sList.item(i);
if (student.getAttribute("examId").equals(examId))
{
//封裝學生物件，返回
Student s = new Student();
s.setExamId(examId);
s.setIdCard(student.getAttribute("idCard"));
s.setName(student.getElementsByTagName("name").item(0).getTextContent());
s.setLocation(student.getElementsByTagName("location").item(0).getTextContent());
s.setGrade(Double.parseDouble(student.getElementsByTagName("grade").item(0).getTextContent()));
//返回學生物件
return s;
}
}
return null;
}
catch (Exception e)
{
// TODO Auto-generated catch block
// e.printStackTrace();
throw new RuntimeException(e);
}
}
public void delete (String name) throws StudentNotExistException
{
try
{
//得到對應XML文件物件
Document document = XMLUtils.getDocument();
//得到學生姓名集合
NodeList nList = document.getElementsByTagName("name");
for (int i = 0; i < nList.getLength(); i++)
{
if (nList.item(i).getTextContent().equals(name))
{
nList.item(i).getParentNode().getParentNode().removeChild(nList.item(i).getParentNode());
//更新文件
XMLUtils.writeToXML(document);
return;
}
}
throw new StudentNotExistException(name+"不存在");
}
catch (StudentNotExistException e)
{
throw e;
}
catch (Exception e)
{
// TODO Auto-generated catch block
throw new RuntimeException(e);
}
}
}
程式入口
package com.stormma.ui;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Scanner;
import com.stormma.dao.StudentDao;
import com.stormma.domain.Student;
import com.stormma.exception.StudentNotExistException;
public class Main
{
/**
* @param args
*/
public static void main(String[] args)
{
// TODO Auto-generated method stub
meun();
// BufferedReader br = new BufferedReader(new
// InputStreamReader(System.in));
Scanner br = new Scanner(System.in);
while (br.hasNext())
{
try
{
String type = br.next();
if (type.equals("a"))
{
System.out.println("請輸入要新增學生的姓名 ");
String name = br.next();
System.out.println("請輸入要新增學生的准考證號 ");
String examId = br.next();
System.out.println("請輸入要新增學生的身份證號 ");
String idCard = br.next();
System.out.println("請輸入要新增學生的出生地 ");
String location = br.next();
System.out.println("請輸入要新增學生的分數 ");
String grade = br.next();
Student s = new Student();
s.setExamId(examId);
s.setName(name);
s.setGrade(Double.parseDouble(grade));
s.setLocation(location);
s.setIdCard(idCard);
StudentDao sd = new StudentDao();
sd.add(s);
System.out.println("新增成功");
} else if (type.equals("b"))
{
System.out.println("請輸入你要刪除的學生的姓名");
String name = br.next();
try
{
StudentDao sd = new StudentDao();
sd.delete(name);
System.out.println("刪除成功");
} catch (StudentNotExistException e)
{
System.out.println("您要刪除的學生不存在");
}
} else if (type.equals("c"))
{
System.out.println("請輸入你要查詢的學生的准考證號");
String examId = br.next();
StudentDao sd = new StudentDao();
if (sd.find(examId) != null)
{
System.out.println(sd.find(examId));
} else
{
System.out.println("您要查詢的學生不存在");
}
} else
{
System.out.println("請鍵入正確的操作");
}
} catch (Exception e)
{
e.printStackTrace();
System.out.println("系統正忙······");
}
}
}
public static void meun()
{
System.out.println("********歡迎進入學生管理系統********");
System.out.println("\t新增使用者：a");
System.out.println("\t刪除使用者：b");
System.out.println("\t查詢使用者：c");
System.out.println("*********************************");
System.out.print("請選擇：");
}
}
自定義異常
package com.stormma.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
}
}