Tapestry 怎样从数据库中保存的图片显示出来。

传个ID给Service让Service输出图片。

类似JSP或SERVELT。。

我仿照TAPESTRY中的AssetService写了个　PhotoService.

java代码:

package outsourcing. tapestry. utils; import java. io. IOException; import javax. servlet. ServletContext; import javax. servlet. ServletException; import org. apache. tapestry. ApplicationRuntimeException; import org. apache. tapestry. IComponent; import org. apache. tapestry. IRequestCycle; import org. apache. tapestry. Tapestry; import org. apache. tapestry. engine. AbstractService; import org. apache. tapestry. engine. IEngineServiceView; import org. apache. tapestry. engine. ILink; import org. apache. tapestry. request. ResponseOutputStream; import org. springframework. context. ApplicationContext; import outsourcing. databean. AgentInformation; import outsourcing. facade. OutSourcingFacade; import outsourcing. tapestry. Engine; /** * @author yin.deng * * TODO 要更改此生成的类型注释的模板，请转至 窗口 － 首选项 － Java － 代码样式 － 代码模板 */ public class PhotoService extends AbstractService {     public static final String SERVICE_NAME = "photo";     public ILink getLink (IRequestCycle cycle, IComponent component,             Object [ ] parameters ) {         if (Tapestry. size (parameters ) != 1 )             throw new ApplicationRuntimeException (Tapestry. format (                     "service-single-parameter", getName ( ) ) );         // Service is stateless         return constructLink (cycle, getName ( ), null, parameters, false );     }     /*      * （非 Javadoc）      *      * @see org.apache.tapestry.engine.AbstractService#getName()      */     public String getName ( ) {         // TODO 自动生成方法存根         return SERVICE_NAME;     }     public void service (IEngineServiceView engine, IRequestCycle cycle,             ResponseOutputStream output ) throws ServletException, IOException {         Object [ ] parameters = getParameters (cycle );         if (Tapestry. size (parameters ) != 1 )             throw new ApplicationRuntimeException (Tapestry. format (                     "service-single-parameter", getName ( ) ) );         String agentid = ( String ) parameters [ 0 ];         ServletContext servletContext = cycle. getRequestContext ( ). getServlet ( )                 . getServletContext ( );         writeAssetContent (engine, cycle, output, agentid, servletContext );     }     /** @since 2.2 * */     private void writeAssetContent (IEngineServiceView engine,             IRequestCycle cycle, ResponseOutputStream output, String agentid,             ServletContext servletContext ) {         // Getting the content type and length is very dependant         // on support from the application server (represented         // here by the servletContext).         String contentType = "image/jpeg";         AgentInformation agentInformation = getOutSourcingFacade (cycle )                 . findAgentById ( Long. valueOf (agentid ) );         output. setContentType (contentType );         // Disable any further buffering inside the ResponseOutputStream         try {             output. forceFlush ( );             output. write (agentInformation. getAiTopo ( ) );         } catch ( IOException e ) {             // TODO 自动生成 catch 块             e. printStackTrace ( );         }     }     private OutSourcingFacade getOutSourcingFacade (IRequestCycle cycle ) {         ApplicationContext applicationContext = this                 . getApplicationContext (cycle );         return (OutSourcingFacade ) applicationContext                 . getBean ("outSourcingFacade" );     }     public ApplicationContext getApplicationContext (IRequestCycle cycle ) {         Engine engine = (Engine ) cycle. getEngine ( );         return engine. getApplicationContext ( );     } }

然后注册到.application中。

java代码:

<?xml version=" 1. 0" encoding="UTF- 8"?> <!DOCTYPE application PUBLIC   "- //Apache Software Foundation//Tapestry Specification 3.0//EN"   "http: //jakarta.apache.org/tapestry/dtd/Tapestry_3_0.dtd"> <application name="outsourcing"     engine- class="outsourcing. tapestry. Engine">     <property name="org. apache. tapestry. output-encoding" value="gb2312"/>     <property name="org. apache. tapestry. template-encoding" value="gb2312"/>     <property name="org. apache. tapestry. visit- class"         value="outsourcing. tapestry. Visit"/>         <service name="report" class="outsourcing. report. ReportService"/>     <service name="photo" class="outsourcing. tapestry. utils. PhotoService"/>     <library id="contrib" specification-path="/org/apache/tapestry/contrib/Contrib. library"/>     <library id="ext" specification-path="/outsourcing/tapestry/jwc/ext. library"/> </application>

在tapestry页面的调用

java代码:

<input jwcid="@ Any" element="img" src= 'ognl:"/galileo/app?service=photo&sp=S" + item.aiId' width=" 600" height=" 400"/>

可以自己再扩展功能。。