DOM解析XML文档实例之学生管理系统

/**
*@ author StormMaybin
*@ date 2016-10-06
*/

主体结构

学生类

package com.stormma.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;
}
@Override
public String toString()
{
// TODO Auto-generated method stub
return "姓名: "+this.name
+"\r\n"+"身份证号："+this.idCard
+"\r\n"+"准考证号："+this.examId
+"\r\n"+"出生地："+this.location
+"\r\n"+"成绩："+this.grade;
}
}

XML工具类

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
{
// 获得工厂实例
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
// 获得解析器
DocumentBuilder builder = factory.newDocumentBuilder();
// 解析文档
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文档的StudentDao类

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;
/**
* 用来和数据库（XML文件）交互
* @author StormMaybin
*  操作：添加学生、查询学生、删除学生
*/
public class StudentDao
{
public void add (Student s)
{
try
{
//得到对应XML文档对象
Document document = XMLUtils.getDocument();

//创建学生标签
Element student_tag = document.createElement("student");
//设置student标签的属性
student_tag.setAttribute("idCard", s.getIdCard());
student_tag.setAttribute("examId", s.getExamId());

//创建student标签的子标签
Element name = document.createElement("name");
Element location = document.createElement("location");
Element grade = document.createElement("grade");

//设置标签内容
name.setTextContent(s.getName());
location.setTextContent(s.getLocation());
grade.setTextContent(s.getGrade()+"");

//建立标签关系
student_tag.appendChild(name);
student_tag.appendChild(location);
student_tag.appendChild(grade);

//得到student父节点
Element exam = (Element) document.getElementsByTagName("exam").item(0);
exam.appendChild(student_tag);

//更新文档内容
XMLUtils.writeToXML(document);
}
catch (Exception e)
{
// TODO Auto-generated catch block
//异常转型
throw new RuntimeException(e);
}
}
public Student find (String examId)
{
try
{
//得到对应XML文档对象
Document document = XMLUtils.getDocument();

//得到学生标签集合
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))
{
//封装学生对象，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()));

//返回学生对象
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
{
//得到对应XML文档对象
Document document = XMLUtils.getDocument();

//得到学生姓名集合
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());
//更新文档
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);
}
}
}

程序入口

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("请输入要添加学生的姓名 ");
String name = br.next();

System.out.println("请输入要添加学生的准考证号 ");
String examId = br.next();

System.out.println("请输入要添加学生的身份证号 ");
String idCard = br.next();

System.out.println("请输入要添加学生的出生地 ");
String location = br.next();

System.out.println("请输入要添加学生的分数 ");
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("添加成功");
} else if (type.equals("b"))
{
System.out.println("请输入你要删除的学生的姓名");
String name = br.next();

try
{
StudentDao sd = new StudentDao();
sd.delete(name);
System.out.println("删除成功");
} catch (StudentNotExistException e)
{
System.out.println("您要删除的学生不存在");
}
} else if (type.equals("c"))
{
System.out.println("请输入你要查询的学生的准考证号");
String examId = br.next();
StudentDao sd = new StudentDao();

if (sd.find(examId) != null)
{
System.out.println(sd.find(examId));
} else
{
System.out.println("您要查找的学生不存在");
}
} else
{
System.out.println("请键入正确的操作");
}
} catch (Exception e)
{
e.printStackTrace();
System.out.println("系统正忙······");
}
}
}

public static void meun()
{
System.out.println("********欢迎进入学生管理系统********");
System.out.println("\t添加用户：a");
System.out.println("\t删除用户：b");
System.out.println("\t查找用户：c");
System.out.println("*********************************");
System.out.print("请选择：");
}
}

自定义异常

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
}
}