一、目標(biāo)
用xml和Xapth做一個(gè)簡(jiǎn)單的數(shù)據(jù)管理系統(tǒng)，對(duì)數(shù)據(jù)的進(jìn)行簡(jiǎn)單的增、刪、改、查詢操作。如做一個(gè)簡(jiǎn)單的班級(jí)學(xué)生信息管理系統(tǒng)：
二、環(huán)境及開(kāi)發(fā)工具
環(huán)境：Java
工具：EcliPSe
開(kāi)發(fā)包：如圖
三、原理
dom4j是一個(gè)Java的XML API，類似于jdom，用來(lái)讀寫(xiě)XML文件的。dom4j是一個(gè)非常非常優(yōu)秀的Java XML API，具有性能優(yōu)異、功能強(qiáng)大和極端易用使用的特點(diǎn)，同時(shí)它也是一個(gè)開(kāi)放源代碼的軟件，可以在SourceForge上找到它。
XPath 是一門(mén)在 XML 文檔中查找信息的語(yǔ)言。XPath 用于在 XML 文檔中通過(guò)元素和屬性進(jìn)行導(dǎo)航。XPath 使用路徑表達(dá)式在 XML 文檔中選取節(jié)點(diǎn)。節(jié)點(diǎn)是通過(guò)沿著路徑或者 step 來(lái)選取的。
用Xpath定位到相應(yīng)節(jié)點(diǎn)，用dom4j進(jìn)行增、刪、改。
四，類分析，如下圖：
addframe：執(zhí)行添加操作時(shí)顯示的界面。
allfunction：對(duì)xml操作各功能的實(shí)現(xiàn)。
alterframe：執(zhí)行修改操作時(shí)顯示的界面。
deleteframe：執(zhí)行刪除操作時(shí)顯示的界面。
mainframe：主界面
queryframe：執(zhí)行查詢操作時(shí)顯示的界面。
五、主要實(shí)現(xiàn)如下：
import java.io.File;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Iterator;
import java.util.List;
import org.dom4j.xpath.*;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.xpath.*;
import org.dom4j.Attribute;
import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;
import org.xml.sax.SAXException;
/**
* @author ncw
* create the function
*/
public class allfunction
{
/*
* 獲取全部信息
*/
public String getall(){
String allinformation="";
try
{
SAXReader saxReader = new SAXReader();
//saxReader.setEncoding("UTF-8");
Document document = saxReader.read(new java.io.File("manage.xml"));
List academylist = document.selectNodes("/school/academy" );
for(int i=0;i<academylist.size();i++)
{
Element academyElement = (Element)academylist.get(i);
allinformation=allinformation+academyElement.attribute("aid").getValue();
allinformation+=" 學(xué)院: "+"\n";
Iterator classiterator = academyElement.elementIterator("class");
while(classiterator.hasNext())
{
Element classElement = (Element)classiterator.next();
allinformation+=classElement.attribute("cid").getValue();
allinformation+=" 班級(jí): "+"\n";
Iterator studentiterator = classElement.elementIterator("student");
while(studentiterator.hasNext())
{
Element studentElement=(Element)studentiterator.next();
allinformation+="姓名：";
allinformation+=studentElement.elementText("name");
allinformation+=" 性別：";
allinformation+=studentElement.elementText("sex");
allinformation+=" 年齡：";
allinformation+=studentElement.elementText("age");
allinformation+=" 成績(jī)：";
allinformation+=studentElement.elementText("grade");
allinformation+="\n";
}
}
}
}catch(Exception ex)
{
ex.printStackTrace();
}
return allinformation;
}
/*
* 獲得一個(gè)學(xué)生的信息
*/
public String getperson(String name)
{
String person="";
try
{
SAXReader saxReader = new SAXReader();
Document document = saxReader.read(new java.io.File("manage.xml"));
List classlist = document.selectNodes("/school/academy/class" );
Iterator classiterator = classlist.iterator();
while(classiterator.hasNext())
{
Element classElement = (Element)classiterator.next();
Iterator studentiterator = classElement.elementIterator("student");
while(studentiterator.hasNext())
{
Element studentElement=(Element)studentiterator.next();
if(studentElement.elementText("name").equals(name))
{
person+="學(xué)院："+classElement.getParent().attributeValue("aid")+"\n";
person+="班級(jí):"+classElement.attributeValue("cid")+"\n";
person+="姓名："+studentElement.elementText("name");
person+=" 性別："+studentElement.elementText("sex");
person+=" 年齡："+studentElement.elementText("age");
person+=" 成績(jī)："+studentElement.elementText("grade");
}
}
}
}catch(Exception ex)
{
ex.printStackTrace();
}
return person;
}
/*
* 刪除一個(gè)學(xué)生的信息
*/
public boolean delete(String name)
{
boolean deleted=false;
try
{
SAXReader saxReader = new SAXReader();
Document document = saxReader.read(new java.io.File("manage.xml"));
List classlist = document.selectNodes("/school/academy/class");
Iterator classiterator = classlist.iterator();
while(classiterator.hasNext())
{
Element classElement = (Element)classiterator.next();
Iterator studentiterator = classElement.elementIterator("student");
while(studentiterator.hasNext())
{
Element studentElement=(Element)studentiterator.next();
if(studentElement.elementText("name").equals(name))
{
classElement.remove(studentElement);
deleted=true;
}
}
}
try{
/** 格式化輸出,類型IE瀏覽一樣 */
OutputFormat format = OutputFormat.createPrettyPrint();
/** 指定XML編碼 */
format.setEncoding("GBK");
/** 將document中的內(nèi)容寫(xiě)入文件中 */
// XMLWriter writer = new XMLWriter(new FileWriter(new File(newfilename)),format);
//保證編碼為UTF-8，支持中文寫(xiě)入
XMLWriter writer = new XMLWriter(new FileOutputStream(new File("manage.xml")),format);
writer.write(document);
writer.close();
}catch(Exception ex){
ex.printStackTrace();
}
}catch(Exception ex)
{
ex.printStackTrace();
}
return deleted;
}
/*
* 修改一個(gè)學(xué)生的信息
*/
public boolean alter(String aid,String cid,String name,String sex,String age,String grade)
{
boolean altered=false;
try{
/*
aid=new String(aid.getBytes("ISO8859-1"),"UTF-8");
cid=new String(cid.getBytes("ISO8859-1"),"UTF-8");
name=new String(name.getBytes("ISO8859-1"),"UTF-8");
sex=new String(sex.getBytes("ISO8859-1"),"UTF-8");
age=new String(age.getBytes("ISO8859-1"),"UTF-8");
grade=new String(grade.getBytes("ISO8859-1"),"UTF-8");
*/
SAXReader saxReader = new SAXReader();
Document document = saxReader.read(new java.io.File("manage.xml"));
List academylist = document.selectNodes("/school/academy" );
Iterator academyiterator = academylist.iterator();
while(academyiterator.hasNext())
{
Element academyElement = (Element) academyiterator.next();
if(academyElement.attribute("aid").getValue().equals(aid));
Iterator classiterator = academyElement.elementIterator("class");
while(classiterator.hasNext())
{
Element classElement = (Element)classiterator.next();
if(classElement.attribute("cid").getValue().equals(cid));
Iterator studentiterator = classElement.elementIterator("student");
while(studentiterator.hasNext())
{
Element studentElement=(Element)studentiterator.next();
if(studentElement.elementText("name").equals(name))
{
Element sexElement=studentElement.element("sex");
sexElement.setText(sex);
Element ageElement=studentElement.element("age");
ageElement.setText(age);
Element gradeElement=studentElement.element("grade");
gradeElement.setText(grade);
altered=true;
}
}
}
}
try{
/** 格式化輸出,類型IE瀏覽一樣 */
OutputFormat format = OutputFormat.createPrettyPrint();
/** 指定XML編碼 */
format.setEncoding("GBK");
/** 將document中的內(nèi)容寫(xiě)入文件中 */
// XMLWriter writer = new XMLWriter(new FileWriter(new File(newfilename)),format);
//保證編碼為UTF-8，支持中文寫(xiě)入
XMLWriter writer = new XMLWriter(new FileOutputStream(new File("manage.xml")),format);
writer.write(document);
writer.close();
}catch(Exception ex){
ex.printStackTrace();
}
}catch(Exception ex)
{
ex.printStackTrace();
}
return altered;
}
/*
* 添加一個(gè)學(xué)生的信息
*/
public boolean add(String aid,String cid,String name,String sex,String age,String grade)
{
boolean add = false;
try {
/*
aid=new String(aid.getBytes("ISO8859-1"),"UTF-8");
cid=new String(cid.getBytes("ISO8859-1"),"UTF-8");
name=new String(name.getBytes("ISO8859-1"),"UTF-8");
sex=new String(sex.getBytes("ISO8859-1"),"UTF-8");
age=new String(age.getBytes("ISO8859-1"),"UTF-8");
grade=new String(grade.getBytes("ISO8859-1"),"UTF-8");
*/
SAXReader saxReader = new SAXReader();
Document document = saxReader.read(new java.io.File("manage.xml"));
List academylist = document.selectNodes("/school/academy");
Iterator academyiterator = academylist.iterator();
while (academyiterator.hasNext())
{
Element academyElement = (Element) academyiterator.next();
if (academyElement.attribute("aid").getValue().equals(aid))
{
Iterator classiterator = academyElement.elementIterator("class");
while (classiterator.hasNext())
{
Element classElement = (Element) classiterator.next();
if (classElement.attribute("cid").getValue().equals(cid))
{
Element studentElement = classElement.addElement("student");
Element nameElement = studentElement.addElement("name");
nameElement.setText(name);
Element sexElement = studentElement.addElement("sex");
sexElement.setText(sex);
Element ageElement = studentElement.addElement("age");
ageElement.setText(age);
Element gradeElement = studentElement.addElement("grade");
gradeElement.setText(grade);
add = true;
}
}
}
}
try{
/** 格式化輸出,類型IE瀏覽一樣 */
OutputFormat format = OutputFormat.createPrettyPrint();
/** 指定XML編碼 */
format.setEncoding("GBK");
/** 將document中的內(nèi)容寫(xiě)入文件中 */
// XMLWriter writer = new XMLWriter(new FileWriter(new File(newfilename)),format);
//保證編碼為UTF-8，支持中文寫(xiě)入
XMLWriter writer = new XMLWriter(new FileOutputStream(new File("manage.xml")),format);
writer.write(document);
writer.close();
}catch(Exception ex){
ex.printStackTrace();
}
}catch(Exception ex)
{
ex.printStackTrace();
}
return add;
}
}alterframe deleteframe mainframe queryframe等類則實(shí)現(xiàn)相應(yīng)的界面顯示。
相應(yīng)xml結(jié)構(gòu)如下：
六：總結(jié)：
1 功能簡(jiǎn)單，操作不夠靈活
2 在對(duì)數(shù)據(jù)的讀入與存儲(chǔ)上有待改進(jìn)。
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