Tapestry 怎样从数据库中保存的图片显示出来。

Posted 2021-10-25 dainiao01

tags:

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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。。

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