J2EE实现XML文件的读取与导出（源码）！

最近学习了XML的相关知识，深感其强大。

XML这个技术家族非常庞大。并且与其他技术密不可分。

是我们非常有必要掌握的知识，然后看了两个视频。把XML关于J2EE这方面做了系统的学习。

总结如下：

搭建环境：MyEclipse6.5

使用jar包jdom.jar

下面首先介绍XML文件读取：

首先在项目中找一个XML文件，我就以以下的XML配置文件为例。

新建一个全局配置文件：gobal-configure.xml

 

<!----> <? xml version="1.0" encoding="UTF-8" ?>
<!--  配置数据库信息  -->
< sys-configure >
     < jdbc-info >
         < driver-class-name > com.mysql.jdbc.Driver </ driver-class-name >
         < url > jdbc:mysql://localhost:3306/sy </ url >
         < user-name > root </ user-name >
         < password > **** </ password >
     </ jdbc-info >
<!--  配置DAO  -->
     < beans >
         < bean  id ="com.sy.dao.ItemDao"  class ="com.sy.dao.impl.ItemDaoImpl" ></ bean >
     </ beans >
</ sys-configure >

 

 下面在com.sy.util包中添加JdbcInfo.java注入类

 

 

<!----> package  com.sy.util;

public   class  JdbcInfo {
    
     private  String driverClassName;
     private  String url;
     private  String userName;
     private  String password;
     public  String getDriverClassName() {
         return  driverClassName;
    }
     public   void  setDriverClassName(String driverClassName) {
         this .driverClassName  =  driverClassName;
    }
     public  String getUrl() {
         return  url;
    }
     public   void  setUrl(String url) {
         this .url  =  url;
    }
    
     public  String getPassword() {
         return  password;
    }
     public   void  setPassword(String password) {
         this .password  =  password;
    }
     public  String toString() {
         return   " JdbcInfo {driverClassName= " + driverClassName +
         " ,url= " + url +
         " ,userName= " + userName +
         " ,password= " + password + " } " ;
    }
     public  String getUserName() {
         return  userName;
    }
     public   void  setUserName(String userName) {
         this .userName  =  userName;
    }

}

 

下面是读取类：GlobalConfigure.java

 

<!----> package  com.sy.util;

import  java.io.IOException;
import  java.util.HashMap;
import  java.util.Iterator;
import  java.util.List;
import  java.util.Map;

import  org.jdom.Document;
import  org.jdom.Element;
import  org.jdom.JDOMException;
import  org.jdom.input.SAXBuilder;
import  org.jdom.xpath.XPath;

import  com.sy.dao.ItemDao;

public   class  GlobalConfigure {

     private   static  GlobalConfigure instance = new  GlobalConfigure();
    
     private   static   final  String CONFIG_FILE_NAME = " gobal-configure.xml " ;
    
     private  Element rootElt;
    
     private  JdbcInfo jdbcInfo = new  JdbcInfo();
    
     private  Map beanMap = new  HashMap();
    
     private  GlobalConfigure(){
        SAXBuilder sb = new  SAXBuilder();
         try  {
            Document doc = sb.build(Thread.currentThread().getContextClassLoader().getResourceAsStream(CONFIG_FILE_NAME));
             this .rootElt = doc.getRootElement();
            initJdbcInfo();
            initBeans();
        }  catch  (JDOMException e) {
             //  TODO Auto-generated catch block
            e.printStackTrace();
        }  catch  (IOException e) {
             //  TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    
     private   static  GlobalConfigure getInstance(){
        
         return  instance;
    }
     private   void  initJdbcInfo(){
         try  {
            Element driverClassNameElt = (Element)XPath.selectSingleNode(rootElt, " //sys-configure/jdbc-info/driver-class-name " );
             // System.out.println(driverClassNameElt.getText());
            jdbcInfo.setDriverClassName(driverClassNameElt.getText());
            Element urlElt = (Element)XPath.selectSingleNode(rootElt, " //sys-configure/jdbc-info/url " );
            jdbcInfo.setUrl(urlElt.getText());
            Element userNameElt = (Element)XPath.selectSingleNode(rootElt, " //sys-configure/jdbc-info/user-name " );
            jdbcInfo.setUserName(userNameElt.getText());
            Element passwordElt = (Element)XPath.selectSingleNode(rootElt, " //sys-configure/jdbc-info/password " );
            jdbcInfo.setPassword(passwordElt.getText());
            
        }  catch  (JDOMException e) {
             //  TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
     private   void  initBeans(){
         try  {
            List beanList = XPath.selectNodes(rootElt,  " //sys-configure/beans/bean " );
             for (Iterator iter = beanList.iterator();iter.hasNext();){
                Element beanElt = (Element)iter.next();
                String id = beanElt.getAttributeValue( " id " );
                String className = beanElt.getAttributeValue( " class " );
                 // System.out.println("id="+id+",className="+className);
                Object obj = Class.forName(className).newInstance();
                beanMap.put(id, obj);
                
                
                
            }
            
            
        }  catch  (JDOMException e) {
             //  TODO Auto-generated catch block
            e.printStackTrace();
        }  catch  (InstantiationException e) {
             //  TODO Auto-generated catch block
            e.printStackTrace();
        }  catch  (IllegalAccessException e) {
             //  TODO Auto-generated catch block
            e.printStackTrace();
        }  catch  (ClassNotFoundException e) {
             //  TODO Auto-generated catch block
            e.printStackTrace();
        }
        
    }
     public   static   void  main(String[] args){
        System.out.println(GlobalConfigure.getInstance().getJdbcInfo());
        ItemDao itemDao = (ItemDao)GlobalConfigure.getInstance().getBean(ItemDao. class );
    }

     public  JdbcInfo getJdbcInfo() {
         return  jdbcInfo;
    }
     public  Object getBean(Class c){
         return  beanMap.get(c.getName());
        
    }
}

这样就可以读取了。

 

 下面是XML文件的导出的类:

<!----> package  com.sy.util;

import  java.io.FileNotFoundException;
import  java.io.FileOutputStream;
import  java.io.IOException;

import  org.jdom.Attribute;
import  org.jdom.Document;
import  org.jdom.Element;
import  org.jdom.output.XMLOutputter;

public   class  XMLWriter {
     /**
     * <selects> 
     *         <select> 
     *             <id sid="5">1</id> 
     *             <name>河北省</name> 
     *         </select> 
     *         <select> 
     *             <id>2</id>
     *             <name>海南省</name> 
     *         </select> 
     * </selects>
     *  @param  args
      */
     public   static   void  main(String[] args) {
        Element rootElt  =   new  Element( " selects " );
        Element selectElt  =   new  Element( " select " );
        Element idElt  =   new  Element( " id " );
        idElt.addContent( " 1 " ); // 设定值
        idElt.setAttribute( new  Attribute( " sid " , " 5 " ));
        Element valueElt  =   new  Element( " name " );
        valueElt.addContent( " 河北省 " );
        rootElt.addContent(selectElt); // 建立父子关系
        selectElt.addContent(idElt);
        selectElt.addContent(valueElt);
        Document doc  = new  Document(rootElt);
        XMLOutputter out  = new  XMLOutputter();
         // out.setFormat(Format.getCompactFormat().setEncoding("GB2312")); // 设置编码
        String xmlStr = out.outputString(doc);
        System.out.println(xmlStr);
         try  {
            out.output(doc,  new  FileOutputStream( " D:/java/work2/jdom_xml2/WebRoot/test.xml " )); // 导出xml文件在项目根目录
        }  catch  (FileNotFoundException e) {
             //  TODO Auto-generated catch block
            e.printStackTrace();
        }  catch  (IOException e) {
             //  TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

}

 

施杨出品！！！