cmd

? <xb:namespace>
??? <xb:package>sample.xmlbean</xb:package>
? </xb:namespace>

</xb:config>

　　四、XMLBean使用步驟

　　和其他面向Java環(huán)境的對象/關(guān)系數(shù)據(jù)庫映射工具的使用步驟一樣,在正式使用XMLBean前,我們要作兩個準備.

　　1. 生成XML Schema文件

　 　什么是XML Schema文件? 正常情況下,每個XML文件都有一個Schema文件,XML Schema文件是一個XML的約束文件,它定義了XML文件的結(jié)構(gòu)和元素.以及對元素和結(jié)構(gòu)的約束. 通俗地講,如果說XML文件是數(shù)據(jù)庫里的記錄,那么Schema就是表結(jié)構(gòu)定義.

　　為什么需要這個文件? XMLBean需要通過這個文件知道一個XML文件的結(jié)構(gòu)以及約束,比如數(shù)據(jù)類型等. 利用這個Schema文件,XMLBean將會產(chǎn)生一系列相關(guān)的Java Classes來實現(xiàn)對XML的操作. 而作為開發(fā)人員,則是利用XMLBean產(chǎn)生的Java Classes來完成對XML的操作而不需要SAX或DOM.怎樣產(chǎn)生這個Schema文件呢? 如果對于熟悉XML的開發(fā)人員,可以自己來寫這個Schema文件,對于不熟悉XML的開發(fā)人員,可以通過一些工具來完成.比較有名的如XMLSPY和 Stylus Studio都可以通過XML文件來生成Schema文件. 加入我們已經(jīng)生成這個Schema文件(customer.xsd):

???????? <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來生成Java Classes

　　scomp是XMLBean提供的一個編譯工具,它在bin的目錄下. 通過這個工具,我們可以將以上的Schema文件生成Java Classes.scomp的語法如下:-

　　scomp [options] [dirs]* [schemaFile.xsd]* [service.wsdl]* [config.xsdconfig]*

　　主要參數(shù)說明:

　　-src [dir] -- 生成的Java Classes存放目錄

　　-srconly -- 不編譯Java Classes,不產(chǎn)生Jar文件

　　-out [jarFileName] -- 生成的Jar文件,缺省是xmltypes.jar

　　-compiler -- Java編譯器的路徑,即Javac的位置

　　schemaFile.xsd -- XML Schema文件位置

　　config.xsdconfig -- xsdconfig文件的位置, 這個文件主要用來制定生成的Java Class的一些文件名規(guī)則和Package的名稱,在本文,package是sample.xmlbean

　　在本文,我是這樣運行的:

????? scomp -src build\src? -out build\customerXmlBean.jar schema\customer.xsd
???????????? -compiler C:\jdk142_04\bin\javac customer.xsdconfig

　 　這個命令行的意思是告訴scomp生成customerXmlBean.jar,放在build目錄下,同時生成源代碼放在build\src下, Schema文件是customer.xsd,xsdconfig文件是customer.xsdconfig.其實, 生成的Java源代碼沒有多大作用,我們要的是jar文件.我們先看一下build\src\sample\xmlbean下生成的Classes.

　　CustomersDocument.java -- 整個XML文檔的Java Class映射

　　CustomerType.java -- 節(jié)點sustomer的映射

　　AddressType.java -- 節(jié)點address的映射

　　BillingAddressType.java -- 節(jié)點billingAddress的映射

　　PrimaryAddressType.java -- 節(jié)點primaryAddress的映射

　　好了,到此我們所有的準備工作已經(jīng)完成了. 下面就開始進入重點:利用剛才生成的jar文件讀寫XML.

　　五、利用XMLBean讀XML文件

　　新建一個Java Project,將XMLBean2.0.0\lib\下的Jar文件和剛才我們生成的customerXmlBean.jar加入到Project的ClassPath.

　　新建一個Java Class: CustomerXMLBean. 源碼如下:

??? 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();
??? }

??? }

　　運行它,參看輸出結(jié)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

　　怎么樣,是不是很輕松? XMLBean的威力.

　　六、利用XMLBean寫XML文件

　　利用XMLBean創(chuàng)建一個XML文檔也是一件輕而易舉的事.我們再增加一個Method,

　　請看一下的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();
??? }

　　運行,打開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

　　我們再增加一個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");
??? }

　　運行之后,我們將會看到客戶編號為3的客戶的lastname已經(jīng)改為last.

　　八、利用XMLBean刪除一個customer

　　再增加一個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);
??? }

　　運行,我們將會看到客戶編號為3的客戶的資料已經(jīng)被刪除.

　　九、查詢XML

　　除了本文在以上講述的,利用XMLBean能輕輕松松完成XML的讀寫操作外,結(jié)合XPath和XQuery,XMLBean還能完成象SQL查詢數(shù)據(jù)庫一樣方便地查詢XML數(shù)據(jù). 關(guān)于XML查詢以及如何創(chuàng)建XML數(shù)據(jù)庫, 我將在另一篇文章里討論.

　　十、結(jié)束語

　　XMLBean能幫助我們輕易讀寫XML,這將有助于我們降低XML的學(xué)習(xí)和使用,有了這個基礎(chǔ),開發(fā)人員將為學(xué)習(xí)更多地XML相關(guān)技術(shù)和Web Services,JMS等其他J2EE技術(shù)打下良好地基礎(chǔ).