XML---学生成绩管理系统之 DOM解析 [方立勋视频讲解]

来源：互联网发布：最好的编程语言编辑：程序博客网时间：2024/04/29 19:40

考生成绩管理系统

可以参考我的有道笔记: http://note.youdao.com/share/?id=711382e33ea8329db35bd4cc5a623b07&type=note

也可直接下载源码: http://download.csdn.net/detail/iknownu/8266553

0、先把思路定下，自下而上构思

0、分析xml 文档

1、daomain/bean/entity

================================

package cn.itcast.domain;

/**
* 2014-12-16 16:10:37
* Student属性是XML文档的标签
* @author yungcs
*
*/
public class Student {

private String idcard; //属性1
private String examid; //属性2
private String name;//姓名
private String location;//住址
private double grade;//分数
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;
}

}
==================================

2、XmlUtils工具类

======================================

package cn.itcast.utils;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.w3c.dom.Document;

//工具包挺长是静态方法

/**
*
* 2014-12-16 下午04:18:50
* @author yungcs
* Xml工具类
*/
public class XmlUtils {

private static String filename = "src/exam.xml";
/**
* 将xml转成document
* @return
* @throws Exception
*/
public static Document getDocument() throws Exception{

  DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); //接口要不是调用静态方法，要不就newinstance
  DocumentBuilder builder = factory.newDocumentBuilder();

  return builder.parse(filename);
}

//thinking in java spring
/**
* 将document转成xml
*/
public static void write2Xml(Document document) throws Exception{

  TransformerFactory factory = TransformerFactory.newInstance();
  Transformer tf = factory.newTransformer();

  tf.transform(new DOMSource(document), new StreamResult(filename));
}

}

=========================================

3、StudentDao

============================

package cn.itcast.dao;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;

import cn.itcast.domain.Student;
import cn.itcast.exception.StudentNotExitsException;
import cn.itcast.utils.XmlUtils;

/**
*
* 2014-12-16 下午04:22:31
* TODO 操作对xml进行增删查
* @author yungcs
*/
public class StudentDao {

/**
* 增加学生根据学生对象 [Student] 增加
*/
public void add(Student s){

  try {
   Document document = XmlUtils.getDocument();//将xml转成document

   //创建出用于封装学生姓名、所在地和成绩的标签
   Element student_tag = document.createElement("student");
   student_tag.setAttribute("idcard", s.getIdcard());
   student_tag.setAttribute("examid", s.getExamid());


   //用于封装学生姓名、所在地和成绩的标签
   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);

   //把封装了信息学生标签，挂到文档上
   document.getElementsByTagName("exam").item(0).appendChild(student_tag);

   XmlUtils.write2Xml(document);//将document转成xml


  } catch (Exception e) {

  // System.out.println("=="+e);
   //[！！！！！！注意！！！！！！！]
   //将运行时异常转成编译时异常，并且在括号内传入异常参数
   //这样是为了把异常的种类报告给上一级
   throw new RuntimeException(e); //uncheck exception（运行时异常）
  }


}

/**
* 查询学生根据    [examid] 查询
*/
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)){
     //
     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;
    }
   }

  } catch (Exception e) {
   throw new RuntimeException(e); //uncheck exception（运行时异常）
  }

  return null;
}

/**
* 删除学生根据姓名 [name] 删
*/
public void delete(String name) throws StudentNotExitsException{
  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 StudentNotExitsException(name+"不存在");
  }catch (StudentNotExitsException e) {
   throw e; //uncheck exception（运行时异常）
  }
  catch (Exception e) {
   throw new RuntimeException(e); //uncheck exception（运行时异常）
  }

}
}

======================================

4、自定义异常

===============================

package cn.itcast.exception;

/**
* 2014-12-16 16:11:24
* 异常统一在一个包类内存放
* @author yungcs
*
*/
public class StudentNotExitsException extends Exception {

public StudentNotExitsException() {
// TODO Auto-generated constructor stub
}

public StudentNotExitsException(String message) {
super(message);
// TODO Auto-generated constructor stub
}

public StudentNotExitsException(Throwable cause) {
super(cause);
// TODO Auto-generated constructor stub
}

public StudentNotExitsException(String message, Throwable cause) {
super(message, cause);
// TODO Auto-generated constructor stub
}

}

=========================

记得勾选倒数第二栏

5、测试类

=================================

package junit.test;

import org.junit.Test;

import cn.itcast.dao.StudentDao;
import cn.itcast.domain.Student;
import cn.itcast.exception.StudentNotExitsException;

/**
* 2014-12-16 16:12:42
* StudentDao 的一个测试类
* @author yungcs
*
*/
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("121");

// System.out.println("--"+dao.find("121").getGrade());
}

@Test
public void testDelete() throws StudentNotExitsException{
  StudentDao dao = new StudentDao();
  dao.delete("aa");
// dao.delete("eee");
// System.out.println("--"+dao.find("121").getGrade());
}
}
==================================

6、主UI程序

====================================

package cn.itcast.UI;

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

import cn.itcast.dao.StudentDao;
import cn.itcast.domain.Student;
import cn.itcast.exception.StudentNotExitsException;

/**
* XML---学生成绩管理系统之 DOM解析
* 2014-12-16 下午04:29:12
* TODO UI界面设计
* @author yungcs
*/
public class Main {

/**
* @param args
* @throws IOException
*/
public static void main(String[] args) {

  try {
   System.out.println("添加学生(a) 删除学生(b) 查找学生(c)");
   System.out.print("请输入操作类型:");

   //读取键盘输入的文字
   BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
   String type = br.readLine();

   if("a".equals(type)){

    System.out.print("请输入学生的姓名：");
    String name = br.readLine();

    System.out.print("请输入学号:");
    String examid = br.readLine();

    System.out.print("请输入身份证号:");
    String idcard = br.readLine();

    System.out.print("请输入学生所在地:");
    String location = br.readLine();

    System.out.print("请输入学生成绩:");
    String grade = br.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:");
    String name = br.readLine();

    try {
     StudentDao dao = new StudentDao();
     dao.delete(name);
     System.out.println("删除成功!!!");
    } catch (StudentNotExitsException e) {
     System.out.println("您要删除的用户不存在!!!");
    }


   }else if("c".equals(type)){
    //自己写了
   }else{
    System.out.println("不支持您的操作！！");
   }

   } catch (IOException e) {
    e.printStackTrace(); //
    System.out.println("对不起，出错了！");
   }


}

}

===========================================

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XML---学生成绩管理系统 之 DOM解析 [方立勋视频讲解]

XML---学生成绩管理系统之 DOM解析 [方立勋视频讲解]