Xml—dom4j解析—学生信息管理系统

Xml文档—exam.xml

<?xml version="1.0" encoding="UTF-8"?>

<exam>
  <student examid="111" idcard="111123123">
    <name>张三</name> 
    <location>沈阳</location> 
    <grade>89</grade>
  </student> 
  <student examid="222" idcard="22212342323">
    <name>李四</name> 
    <location>大连</location> 
    <grade>97</grade>
  </student>
</exam>

程序实现：用户对xml文档的添加、删除、查询。

 

封装数据的Student类

package yyy.exam.domain;

 

public class Student {
 private String examid;
 private String idcard;
 private String name;
 private String location;
 private double grade;
 public String getExamid() {
  return examid;
 }
 public void setExamid(String examid) {
  this.examid = examid;
 }
 public String getIdcard() {
  return idcard;
 }
 public void setIdcard(String idcard) {
  this.idcard = idcard;
 }
 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() {
  return "学生姓名:"+name+"/r/n准考证号:"+examid+"/r/n身份证号:"+idcard+"/r/n家庭住址:"+location+"/r/n成绩:"+grade;
 }
 
}

 

 

工具类—XmlUtils

package yyy.exam.utils;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;

 

public class XmlUtils {
 private static File file = new File("src/exam.xml");
 
 public static Document getDocument() throws DocumentException{
  SAXReader reader = new SAXReader();
  Document document = reader.read(file);
  return document;
 }
 
 public static void write2Xml(Document document) throws IOException{
  OutputFormat format = OutputFormat.createPrettyPrint();   //特别要注意乱码问题
  XMLWriter writer = new XMLWriter(new FileOutputStream(file),format);
  writer.write(document);
  writer.close();
 }
}

 

方法类—StudentDao

package yyy.exam.dao;

import java.util.ArrayList;
import java.util.List;

import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.Node;

import yyy.exam.domain.Student;
import yyy.exam.utils.XmlUtils;

 

public class StudentDao {
 
 public static void add(Student student){
  try {
   Document document = XmlUtils.getDocument();   //获得document对象
   Element root = document.getRootElement();   //获得跟节点
   Element student_node = root.addElement("student");   //添加名为student的新节点
   student_node.addAttribute("examid", student.getExamid());  //为student节点添加属性
   student_node.addAttribute("idcard", student.getIdcard());
   student_node.addElement("name").setText(student.getName());   //为student节点添加子节点
   student_node.addElement("location").setText(student.getLocation());
   student_node.addElement("grade").setText(student.getGrade()+"");  //任何对象和字符串相连都是字符串
   
   XmlUtils.write2Xml(document);    //写入xml文档
   
  } catch (Exception e) {
   throw new RuntimeException(e);
  }
 }
 
 public static int delete(String examid){
  try {
   int count = 0;   //定义count记录所删除的学生信息个数
   Document document = XmlUtils.getDocument();
   List<Element> list = document.selectNodes("//student[@examid]");  //获得所有包含examid属性的student元素的集合   Xpath技术
   for(Element node : list){
    if(node.attributeValue("examid").equals(examid)){
     node.getParent().remove(node);
     XmlUtils.write2Xml(document);
     count++;
    }
   }
   return count;
  } catch (Exception e) {
   throw new RuntimeException(e);
  }
 }
 public static ArrayList<Student> find(String name){
  try {
   ArrayList<Student> students = new ArrayList<Student>();  //创建ArrayList集合用于存储查找到的student对象
   Document document = XmlUtils.getDocument();
   List<Node> list = document.selectNodes("//name");   //获得所有的name节点   Xpath技术
   for(Node node : list){
    if(node.getText().equals(name)){
     Student student = new Student();
     student.setName(name);
     student.setExamid(node.getParent().attributeValue("examid"));
     student.setGrade(Double.parseDouble(node.getParent().elementText("grade")));
     student.setIdcard(node.getParent().attributeValue("idcard"));
     student.setLocation(node.getParent().elementText("location"));
     students.add(student);
    }
   }
   return students;   //返回包含所查到的所有student对象的ArrayList集合
  } catch (Exception e) {
   throw new RuntimeException(e);
  }
 }
}

 

 

 

用户界面—主运行类—Main

package yyy.exam.UI;

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

import yyy.exam.dao.StudentDao;
import yyy.exam.domain.Student;

 

public class Main {

 private static Student student = new Student();
 private static StudentDao dao = new StudentDao();
 public static void main(String[] args) {
  
  Operation();
 }

 private static void Operation() {
  try {
   System.out.println("请选择操作类型: 添加学生信息:(a)  删除学生信息:(b)  查看学生信息:(c)  退出;(quit)");
   System.out.print("请选择操作类型:");
   BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
   String type = br.readLine();   //定义type记录用户选择的操作类型
   if("a".equals(type)){
    addStudent(br);
   
   }else if("b".equals(type)){
    deleteStudent(br);
    return;
   }else if("c".equals(type)){
    findStudent(br);
    return;
   }else if("quit".equals(type)){
    System.out.println("谢谢使用,欢迎下次光临！！！！");
    return;
   }else{
    System.out.println("选择操作类型错误，请重新选择！！");
    System.out.print("请选择操作类型:");
    Operation();
   }
  } catch (Exception e) {
   e.printStackTrace();
   System.out.println("程序出现未知错误，请致电1384389438！！！");
  }
 }

 private static void findStudent(BufferedReader br)  {
  try {
   System.out.print("请输入学生姓名:");
   String name = br.readLine();
   ArrayList<Student> list = dao.find(name);
   if(list.size()>0){  //不能用"list==null"做条件，因为list不为空。
    int count = 1;   //定义count记录list集合中存储的学生信息个数
    System.out.println("共找到"+list.size()+"个符合条件的学生信息");
    for(Student student : list){   //遍历list集合打印学生信息
     System.out.println();
     System.out.println("学生"+count+":");
     System.out.println(student);
     count++;
    }
   }else{
    System.out.println("没有此学生信息，请检查姓名是否输入正确！！！");
   }
   System.out.println("yes:继续查找   no:返回上一层");
   String type = br.readLine();
   if("yes".equals(type))
    findStudent(br);  //用户输入yes继续该操作
   else if("no".equals(type))
    Operation();  //用户输入no返回上层继续操作
   else
    System.out.println("输入错误，你个傻B！！！");
  } catch (Exception e) {
   e.printStackTrace();
   System.out.println("程序出现未知错误，请致电1384389438！！！");
  }
 }

 private static void deleteStudent(BufferedReader br) {
  try {
   System.out.print("请输入学生准考证号:");
   String examid = br.readLine();
   int count = dao.delete(examid);   //count记录所删除的学生信息的个数
   if(count!=0){
    System.out.println("删除学生信息成功！！");
    System.out.println("共删除"+count+"个准考证号为"+examid+"的学生信息");
   }else{
    System.out.println("没有此学生信息，请检查准考证号是否输入正确！！！");
   }
   System.out.println("yes:继续删除   no:返回上一层");
   String type = br.readLine();
   if("yes".equals(type))
    deleteStudent(br);  //用户输入yes继续该操作
   else if("no".equals(type))
    Operation();  //用户输入no返回上层继续操作
   else
    System.out.println("输入错误，你个傻B！！！");
  } catch (Exception e) {
   e.printStackTrace();
   System.out.println("程序出现未知错误，请致电1384389438！！！");
  }
 }

 private static void addStudent(BufferedReader br) {
  try {
   System.out.print("请输入学生姓名:");
   String name = br.readLine();
   System.out.print("请输入学生准考证号:");
   String examid = br.readLine();
   System.out.print("请输入学生身份证号:");
   String idcard = br.readLine();
   System.out.print("请输入学生家庭住址:");
   String location = br.readLine();
   System.out.print("请输入学生成绩:");
   String grade = br.readLine();
   
   student.setExamid(examid); 
   student.setGrade(Double.parseDouble(grade));
   student.setIdcard(idcard);
   student.setLocation(location);
   student.setName(name);
   dao.add(student);
   
   System.out.println("添加学生信息成功");
   System.out.println("yes:继续添加   no:返回上一层");
   String type = br.readLine();
   if("yes".equals(type))
    addStudent(br);  //用户输入yes继续该操作
   else if("no".equals(type))
    Operation();  //用户输入no返回上层继续操作
   else
    System.out.println("输入错误，你个傻B！！！");
  } catch (Exception e) {
   e.printStackTrace();
   System.out.println("程序出现未知错误，请致电1384389438！！！");
  }
 }

}