xmlbens

三、准备XMLBean和XML文档  
 
　　XMLBean是Apache的一个开源项目,可以从http://www.apache.org下载,最新的版本是2.0. 解压后目录如下:  
 
xmlbean2.0.0 
     +---bin  
     +---docs  
     +---lib  
     +---samples  
     +---schemas  
 
　　另外还要准备一个XML文档(customers.xml),  
 
　　在本文的例子里,我们将对这个文档进行读写操作. 文档源码如下:  
 
<?xml version="1.0" encoding="UTF-8"?>  
<Customers>  
    <customer>  
            <id>1</id>  
            <gender>female</gender>  
            <firstname>Jessica</firstname>  
            <lastname>Lim</lastname>  
            <phoneNumber>1234567</phoneNumber>  
            <address>  
                <primaryAddress>  
                        <postalCode>350106</postalCode>  
                        <addressLine1>#25-1</addressLine1>  
                        <addressLine2>SHINSAYAMA 2-CHOME</addressLine2>  
                </primaryAddress>  
                <billingAddress>  
                        <receiver>Ms Danielle</receiver>  
                        <postalCode>350107</postalCode>  
                        <addressLine1>#167</addressLine1>  
                        <addressLine2>NORTH TOWER HARBOUR CITY</addressLine2>  
                </billingAddress>  
            </address>  
    </customer>  
    <customer>  
            <id>2</id>  
            <gender>male</gender>  
            <firstname>David</firstname>  
            <lastname>Bill</lastname>  
            <phoneNumber>808182</phoneNumber>  
            <address>  
                <primaryAddress>  
                        <postalCode>319087</postalCode>  
                        <addressLine1>1033 WS St.</addressLine1>  
                        <addressLine2>Tima Road</addressLine2>  
                </primaryAddress>  
                <billingAddress>  
                        <receiver>Mr William</receiver>  
                        <postalCode>672993</postalCode>  
                        <addressLine1>1033 WS St.</addressLine1>  
                        <addressLine2>Tima Road</addressLine2>  
                </billingAddress>  
            </address>  
    </customer>  
</Customers>  
 
　　这是一个客户的数据模型,每个客户都有客户编号(ID),姓名,性别(gender),电话号码(phoneNumber)和地址,其中地址有两个: 首要地址(PrimaryAddress)和帐单地址(BillingAddress),每个地址有邮编,地址1,和地址2组成.其中帐单地址还有收件人(receiver).此外,还要准备一个配置文件(文件名customer.xsdconfig),这个文件的作用我后面会讲,它的内容如下:  
 
<xb:config xmlns:xb="http://xml.apache.org/xmlbeans/2004/02/xbean/config">  
 
  <xb:namespace>  
    <xb:package>sample.xmlbean</xb:package>  
  </xb:namespace>  
 
</xb:config>  
 
　　四、XMLBean使用步骤  
 
　　和其他面向Java环境的对象/关系数据库映射工具的使用步骤一样,在正式使用XMLBean前,我们要作两个准备.  
 
　　1. 生成XML Schema文件  
 
　　什么是XML Schema文件? 正常情况下,每个XML文件都有一个Schema文件,XML Schema文件是一个XML的约束文件,它定义了XML文件的结构和元素.以及对元素和结构的约束. 通俗地讲,如果说XML文件是数据库里的记录,那么Schema就是表结构定义.  
 
　　为什么需要这个文件? XMLBean需要通过这个文件知道一个XML文件的结构以及约束,比如数据类型等. 利用这个Schema文件,XMLBean将会产生一系列相关的Java Classes来实现对XML的操作. 而作为开发人员,则是利用XMLBean产生的Java Classes来完成对XML的操作而不需要SAX或DOM.怎样产生这个Schema文件呢? 如果对于熟悉XML的开发人员,可以自己来写这个Schema文件,对于不熟悉XML的开发人员,可以通过一些工具来完成.比较有名的如XMLSPY和Stylus Studio都可以通过XML文件来生成Schema文件. 加入我们已经生成这个Schema文件(customer.xsd):  
 
       <?xml version="1.0" encoding="UTF-8"?>  
       <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" 
                  elementFormDefault="qualified">  
         <xs:element name="Customers">  
           <xs:complexType>  
             <xs:sequence>  
               <xs:element maxOccurs="unbounded" name="customer" 
                           type="customerType"/>  
             </xs:sequence>  
           </xs:complexType>  
         </xs:element>  
       <xs:complexType name="customerType">  
             <xs:sequence>  
               <xs:element name="id" type="xs:int"/>  
               <xs:element name="gender" type="xs:string"/>  
               <xs:element name="firstname" type="xs:string"/>  
               <xs:element name="lastname" type="xs:string"/>  
               <xs:element name="phoneNumber" type="xs:string"/>  
               <xs:element name="address" type="addressType"/>  
             </xs:sequence>  
       </xs:complexType>  
         <xs:complexType name="addressType">  
             <xs:sequence>  
               <xs:element name="primaryAddress" type="primaryAddressType"/>  
               <xs:element name="billingAddress" type="billingAddressType"/>  
             </xs:sequence>  
         </xs:complexType>  
 
   <xs:complexType name="primaryAddressType">  
             <xs:sequence>  
               <xs:element name="postalCode" type="xs:string"/>  
               <xs:element name="addressLine1" type="xs:string"/>  
               <xs:element name="addressLine2" type="xs:string"/>  
             </xs:sequence>  
         </xs:complexType>  
         <xs:complexType name="billingAddressType">  
             <xs:sequence>  
                   <xs:element name="receiver" type="xs:string"/>  
               <xs:element name="postalCode" type="xs:string"/>  
               <xs:element name="addressLine1" type="xs:string"/>  
               <xs:element name="addressLine2" type="xs:string"/>  
             </xs:sequence>  
         </xs:complexType>  
       </xs:schema>  
 
　　2. 利用scomp来生成Java Classes  
 
　　scomp是XMLBean提供的一个编译工具,它在bin的目录下. 通过这个工具,我们可以将以上的Schema文件生成Java Classes.scomp的语法如下:-  
 
　　scomp [options] [dirs]* [schemaFile.xsd]* [service.wsdl]* [config.xsdconfig]*  
 
　　主要参数说明:  
 
　　-src [dir] -- 生成的Java Classes存放目录  
 
　　-srconly -- 不编译Java Classes,不产生Jar文件  
 
　　-out [jarFileName] -- 生成的Jar文件,缺省是xmltypes.jar  
 
　　-compiler -- Java编译器的路径,即Javac的位置  
 
　　schemaFile.xsd -- XML Schema文件位置  
 
　　config.xsdconfig -- xsdconfig文件的位置, 这个文件主要用来制定生成的Java Class的一些文件名规则和Package的名称,在本文,package是sample.xmlbean  
 
　　在本文,我是这样运行的:  
 
      scomp -src build\src  -out build\customerXmlBean.jar schema\customer.xsd  
             -compiler C:\jdk142_04\bin\javac customer.xsdconfig  
 
　　这个命令行的意思是告诉scomp生成customerXmlBean.jar,放在build目录下,同时生成源代码放在build\src下, Schema文件是customer.xsd,xsdconfig文件是customer.xsdconfig.其实, 生成的Java源代码没有多大作用,我们要的是jar文件.我们先看一下build\src\sample\xmlbean下生成的Classes.  
 
　　CustomersDocument.java -- 整个XML文档的Java Class映射  
 
　　CustomerType.java -- 节点sustomer的映射  
 
　　AddressType.java -- 节点address的映射  
 
　　BillingAddressType.java -- 节点billingAddress的映射  
 
　　PrimaryAddressType.java -- 节点primaryAddress的映射  
 
　　好了,到此我们所有的准备工作已经完成了. 下面就开始进入重点:利用刚才生成的jar文件读写XML.  
 
　　五、利用XMLBean读XML文件  
 
　　新建一个Java Project,将XMLBean2.0.0\lib\下的Jar文件和刚才我们生成的customerXmlBean.jar加入到Project的ClassPath.  
 
　　新建一个Java Class: CustomerXMLBean. 源码如下:  
 
    package com.sample.reader;  
 
    import java.io.File;  
      
    import sample.xmlbean.*;  
    import org.apache.commons.beanutils.BeanUtils;  
    import org.apache.xmlbeans.XmlOptions;  
    public class CustomerXMLBean {  
    private String filename = null;  
      
    public CustomerXMLBean(String filename) {  
            super();  
            this.filename = filename;  
    }  
 
    public void customerReader() {  
            try {  
              File xmlFile = new File(filename);  
              CustomersDocument doc = CustomersDocument.Factory.parse(xmlFile);  
              CustomerType[] customers = doc.getCustomers().getCustomerArray();  
            
              for (int i = 0; i < customers.length; i++) {  
                CustomerType customer = customers[i];  
                println("Customer#" + i);  
                println("Customer ID:" + customer.getId());  
                println("First name:" + customer.getFirstname());  
                println("Last name:" + customer.getLastname());  
                println("Gender:" + customer.getGender());  
                println("PhoneNumber:" + customer.getPhoneNumber());  
                // Primary address  
                PrimaryAddressType primaryAddress = customer.getAddress().getPrimaryAddress();  
                println("PrimaryAddress:");  
                println("PostalCode:" + primaryAddress.getPostalCode());  
                println("AddressLine1:" + primaryAddress.getAddressLine1());  
                println("AddressLine2:" + primaryAddress.getAddressLine2());  
                // Billing address  
                BillingAddressType billingAddress = customer.getAddress().getBillingAddress();  
                println("BillingAddress:");  
                println("Receiver:" + billingAddress.getReceiver());  
                println("PostalCode:" + billingAddress.getPostalCode());  
                println("AddressLine1:" + billingAddress.getAddressLine1());  
                println("AddressLine2:" + billingAddress.getAddressLine2());  
              
              }  
            } catch (Exception ex) {  
                    ex.printStackTrace();  
            }  
    }  
    private void println(String str) {  
          System.out.println(str);  
    }  
   public static void main(String[] args) {  
      String filename = "F://JavaTest//Eclipse//XMLBean//xml//customers.xml";  
                     
     CustomerXMLBean customerXMLBean = new CustomerXMLBean(filename);  
                   customerXMLBean.customerReader();  
    }  
 
}  
 
　　运行它,参看输出结果:  
 
       Customer#0 
       Customer ID:1 
       First name:Jessica  
       Last name:Lim  
       Gender:female  
       PhoneNumber:1234567 
       PrimaryAddress:  
       PostalCode:350106 
       AddressLine1:#25-1 
       AddressLine2:SHINSAYAMA 2-CHOME  
       BillingAddress:  
       Receiver:Ms Danielle  
       PostalCode:350107 
       AddressLine1:#167 
       AddressLine2:NORTH TOWER HARBOUR CITY  
 
       Customer#1 
       Customer ID:2 
       First name:David  
       Last name:Bill  
       Gender:male  
       PhoneNumber:808182 
       PrimaryAddress:  
       PostalCode:319087 
       AddressLine1:1033 WS St.  
       AddressLine2:Tima Road  
       BillingAddress:  
       Receiver:Mr William  
       PostalCode:672993 
       AddressLine1:1033 WS St.  
       AddressLine2:Tima Road  
 
　　怎么样,是不是很轻松? XMLBean的威力.  
 
　　六、利用XMLBean写XML文件  
 
　　利用XMLBean创建一个XML文档也是一件轻而易举的事.我们再增加一个Method,  
 
　　请看一下的Java Class:  
 
    public void createCustomer() {  
    try {  
        // Create Document  
        CustomersDocument doc = CustomersDocument.Factory.newInstance();  
        // Add new customer  
        CustomerType customer = doc.addNewCustomers().addNewCustomer();  
        // set customer info  
        customer.setId(3);  
        customer.setFirstname("Jessica");  
        customer.setLastname("Lim");  
        customer.setGender("female");  
        customer.setPhoneNumber("1234567");  
        // Add new address  
        AddressType address = customer.addNewAddress();  
        // Add new PrimaryAddress  
        PrimaryAddressType primaryAddress = address.addNewPrimaryAddress();  
        primaryAddress.setPostalCode("350106");  
        primaryAddress.setAddressLine1("#25-1");  
        primaryAddress.setAddressLine2("SHINSAYAMA 2-CHOME");  
 
// Add new BillingAddress  
        BillingAddressType billingAddress = address.addNewBillingAddress();  
        billingAddress.setReceiver("Ms Danielle");  
        billingAddress.setPostalCode("350107");  
        billingAddress.setAddressLine1("#167");  
        billingAddress.setAddressLine2("NORTH TOWER HARBOUR CITY");  
 
        File xmlFile = new File(filename);  
        doc.save(xmlFile);  
        } catch (Exception ex) {  
                ex.printStackTrace();  
        }  
 
  }  
 
　　修改main method.  
 
    public static void main(String[] args) {  
    String filename = "F://JavaTest//Eclipse//XMLBean//xml//customers_new.xml";  
        CustomerXMLBean customerXMLBean = new CustomerXMLBean(filename);  
        customerXMLBean.createCustomer();  
    }  
 
　　运行,打开customers_new.xml:  
 
    <?xml version="1.0" encoding="UTF-8"?>  
    <Customers>  
    <customer>  
            <id>3</id>  
            <gender>female</gender>  
            <firstname>Jessica</firstname>  
            <lastname>Lim</lastname>  
            <phoneNumber>1234567</phoneNumber>  
            <address>  
                    <primaryAddress>  
                         <postalCode>350106</postalCode>  
                         <addressLine1>#25-1</addressLine1>  
                                       <addressLine2>SHINSAYAMA 2-CHOME</addressLine2>  
                    </primaryAddress>  
                    <billingAddress>  
                        <receiver>Ms Danielle</receiver>  
                        <postalCode>350107</postalCode>  
                       <addressLine1>#167</addressLine1>  
                       <addressLine2>NORTH TOWER HARBOUR CITY</addressLine2>  
                    </billingAddress>  
                    </address>  
            </customer>  
    </Customers>  
 
　　七、利用XMLBean修改XML文件  
 
　　我们再增加一个Method:  
 
      public void updateCustomer(int id,String lastname) {  
         try {  
        File xmlFile = new File(filename);  
        CustomersDocument doc = CustomersDocument.Factory.parse(xmlFile);  
        CustomerType[] customers = doc.getCustomers().getCustomerArray();  
        
        for (int i = 0; i < customers.length; i++) {  
           CustomerType customer = customers[i];  
          if(customer.getId()==id){  
                customer.setLastname(lastname);  
                break;  
            }  
        }  
        doc.save(xmlFile);  
         } catch (Exception ex) {  
          ex.printStackTrace();  
         }  
           }  
 
　　main method:  
 
    public static void main(String[] args) {  
     String filename = "F://JavaTest//Eclipse//XMLBean//xml//customers_new.xml";  
                      
    CustomerXMLBean customerXMLBean = new CustomerXMLBean(filename);  
                      
    customerXMLBean.updateCustomer(3,"last");  
    }  
 
　　运行之后,我们将会看到客户编号为3的客户的lastname已经改为last.  
 
　　八、利用XMLBean删除一个customer  
 
　　再增加一个Method:  
 
    public void deleteCustomer(int id) {  
     try {  
      File xmlFile = new File(filename);  
     CustomersDocument doc = CustomersDocument.Factory.parse(xmlFile);  
    CustomerType[] customers = doc.getCustomers().getCustomerArray();  
 
   for (int i = 0; i < customers.length; i++) {  
        CustomerType customer = customers[i];  
        if(customer.getId()==id){  
                        customer.setNil() ;  
                        break;  
               }  
   }  
   doc.save(xmlFile);  
   } catch (Exception ex) {  
        ex.printStackTrace();  
        }  
   }  
 
main method:  
 
    public static void main(String[] args) {  
    String filename = "F://JavaTest//Eclipse//XMLBean//xml//customers_new.xml";  
                      
    CustomerXMLBean customerXMLBean = new CustomerXMLBean(filename);  
                      
    customerXMLBean.deleteCustomer(3);  
    }  
 
　　运行,我们将会看到客户编号为3的客户的资料已经被删除.  
 
　　九、查询XML  
 
　　除了本文在以上讲述的,利用XMLBean能轻轻松松完成XML的读写操作外,结合XPath和XQuery,XMLBean还能完成象SQL查询数据库一样方便地查询XML数据. 关于XML查询以及如何创建XML数据库, 我将在另一篇文章里讨论.  
 
　　十、结束语  
 
　　XMLBean能帮助我们轻易读写XML,这将有助于我们降低XML的学习和使用,有了这个基础,开发人员将为学习更多地XML相关技术和Web Services,JMS等其他J2EE技术打下良好地基础.