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          使用XMLBeans 進行java 數據梆定

          進入實踐之前,最好找篇文章先了解一下 xmlbeans 是用來做什么的
          參考資料:http://xmlbeans.apache.org/
          參考文章:XML-Java Data Binding Using XMLBeans

          xmlbeans bea 貢獻的一個開源項目,目的是使xml 文件直接轉化為java 對象,對java 對象的操作可直接存為xml 文件,省去了文檔驗證過程。
          實現原理:先定義 xml schema descripter ,編譯定義的 *.xsd 文件,引入編譯后生成的.jar 包。與 xmlbeans-Home\lib\xbean.jar  就可以在開發項目中使用了。

          1. Install XMLBeans.
          2. Compile your schema. Use scomp to compile the schema, generating and jarring Java types. For example, to create a employeeschema.jar from an employeesschema.xsd file:
            scomp -out employeeschema.jar employeeschema.xsd
          3. Write code. With the generated JAR on your classpath, write code to bind an XML instance to the Java types representing your schema. Here's an example that would use types generated from an employees schema:
            File xmlFile = new File("c:\employees.xml"); 
            
            // Bind the instance to the generated XMLBeans types.
            EmployeesDocument empDoc = 
            	EmployeesDocument.Factory.parse(xmlFile); 
            
            // Get and print pieces of the XML instance.
            Employees emps = empDoc.getEmployees(); 
            Employee[] empArray = emps.getEmployeeArray(); 
            for (int i = 0; i < empArray.length; i++) 
            { 
            	System.out.println(empArray[i]); 
            }
          實踐中遇到的問題:
          如何修改編譯shema 產生的java 類的package 目錄結構?


          參考:http://wiki.apache.org/xmlbeans/XmlBeansFaq#configPackageName

          Can I change the default package names for the java classes generated from my schema?

          You can create a file that ends in .xsdconfig to map targetnamespace to packagename. Put the .xsdconfig file in the same directory as the .xsd that you are compiling. Here is an example .xsdconfig:

          <!-- An xsdconfig file must begin with a "config" element in the 
                  http://www.bea.com/2002/09/xbean/config namespace. Also, be sure
                  to declare any namespaces used to qualify types in your schema (here,
                  the namespace corresponding to the pol prefix. -->
          <xb:config xmlns:pol="http://openuri.org/easypoLocal" 
              xmlns:xb="http://www.bea.com/2002/09/xbean/config">
          
              <!-- Use the "namespace" element to map a namespace to the Java package
                  name that should be generated. -->
              <xb:namespace uri="http://openuri.org/easypoLocal">
                  <xb:package>org.openuri.easypo.xsdconfig</xb:package>
              </xb:namespace>
          
              <!-- Use the "qname" element to map schema type names to generated
                  Java type names. In these examples, the name attribute's value is the
                  XML element name; the javaname attribute's value is the Java type 
                  that should be generated. -->
              <xb:qname name="pol:CUST" javaname="Customer"/>
              <xb:qname name="pol:PURCH_ORDER" javaname="PurchaseOrder"/>
          </xb:config>
          

          Notice that you can also map specific element/attribute names to java names.

          /!\ Note: If schema doesn't include targenamespace then use

          <xb:namespace uri="##any">
            <xb:package>org.openuri.easypo.xsdconfig</xb:package>
          </xb:namespace>
          

          to specify package names

          /!\ Note: XmlBeans doesn’t support using two or more sets of java classes (in different packages) mapped to schema types/elements that have the same names and target namespaces, using all in the same class loader. Depending on the direction you are using for the java classes to schema types mapping, some features might not work correctly. This is because even though the package names for the java classes are different, the schema location for the schema metadata (.xsb files) is the same and contains the corresponding implementing java class, so the JVM will always pick up the first on the classpath. This can be avoided if multiple class loaders are used.


          先看一下 scomp 命令: xmlbeans-home/bin 要加入到path 中,

          scomp 參數圖
          編寫自己的schema文件:weather_latlong.xsd
          <xsd:schema
          xmlns:xsd="http://www.w3.org/2001/XMLSchema"
          xmlns:ct
          ="http://beans.jhalo.com"
          targetNamespace
          ="http://beans.jhalo.com"
          elementFormDefault
          ="qualified">
          <!-- This XML Schema describes xml documents
          containing either weather details or latlong
          details of a location based on Zipcode Two Global
          elements Weather and Latlong, and one Global
          Attribute Zipcode are declared.
          -->
           
          <xsd:element name="Weather">
            
          <xsd:complexType>
             
          <xsd:sequence>
              
          <xsd:element name="Temperature"
                   type
          ="xsd:float"/>
              
          <xsd:element name="Humidity"
                   type
          ="xsd:float"/>
              
          <xsd:element name="Visibility"
                   type
          ="xsd:float"/>
              
          <xsd:element name="Datetime"
                   type
          ="xsd:dateTime"/>
             
          </xsd:sequence>
            
          <xsd:attribute ref="ct:Zipcode"/>
           
          </xsd:complexType>
           
          </xsd:element>
           
          <xsd:element name="Latlong">
            
          <xsd:complexType>
             
          <xsd:sequence>
              
          <xsd:element name="Latitude"
                   type
          ="xsd:string"/>
              
          <xsd:element name="Longitude"
                   type
          ="xsd:string"/>
              
          </xsd:sequence>
             
          <xsd:attribute ref="ct:Zipcode"/>
            
          </xsd:complexType>
           
          </xsd:element>
           
          <xsd:attribute name="Zipcode"
                   type
          ="xsd:string"/>
          </xsd:schema>


          #


          2
          編寫myconfig.xsdconfig 存放同一目錄


          #
          <xb:config xmlns:xb="http://xml.apache.org/xmlbeans/2004/02/xbean/config"
                     xmlns:ct
          ="http://beans.jhalo.com">

            
          <xb:namespace uri="http://beans.jhalo.com http://services.jhalo.com">
              
          <xb:package>org.jhalo</xb:package>
            
          </xb:namespace> 

            
          <xb:namespace uri="##any">
              
          <xb:prefix>Xml</xb:prefix>
              
          <xb:suffix>Bean</xb:suffix>
            
          </xb:namespace>


            
            
          <xb:qname name="ct:Zipcode" javaname="Zip" /> 
            
          <xb:qname name="ct:Datetime" javaname="Today" />


          </xb:config>


          如果不使用myconfig.xsdconfig 進行編譯
          scomp -out weather.jar weather_latlong.xsd 
          生成的 weather.jar 為:com/jhalo/beans/xxxx


          使用 .xsdconfig 編譯
          scomp -out weather.jar weather_latlong.xsd  myconfig.xsdconfig
          生成jar 結構為: org/jhalo/

          在寫測試程序發現, Datetime -->Today 也改變了。
          import org.apache.xmlbeans.*;
          import org.jhalo.XmlLatlongDocumentBean;
          import org.jhalo.XmlWeatherDocumentBean;


          XmlWeatherDocumentBean wdoc;
          XmlWeatherDocumentBean.Weather w;
          wdoc 
          = XmlWeatherDocumentBean.Factory.newInstance();
          = wdoc.addNewWeather();
          w.setToday(Calendar.getInstance());

          完畢.:)~


          方向:分布式系統設計

          posted on 2006-02-14 16:13 java光環 閱讀(1238) 評論(0)  編輯  收藏 所屬分類: xml


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