如何使用数据库中的 primefaces 在数据表中加载动态图像？图像未显示在数据表中

Question

我正在使用 primfaces 5 版本在数据表中显示我的数据库中的图像，但不幸的是，不是实际图像“图像”被写入列中，这是我的 xhtml 文件。 我有一个带有 StreamedContent 属性的对象列表，我需要在组件中显示它。 我扔了展示的primefaces没有结果

  <p:dataTable id="dta" value="#{UtilisateurComponent.listUtilisateurs()}"  var="current" rows="15" paginator="true" paginatorPosition="bottom" rowKey="current.iduser">
        <p:column> 
                    <f:facet name="header">
                        <h:outputText value="id User" />
                    </f:facet>
                    <h:outputText value="#{current.iuser}"  />
        </p:column>
        <p:column > 
                    <f:facet name="header">
                        <h:outputText value="Photo" />
                    </f:facet>
                        <p:graphicImage  value="#{UtilisateurComponent.content}" height="100" width="150">
                            <f:param name="id" value="#{current.iduser}" />
                        </p:graphicImage>
        </p:column>
  </p:dataTable>

这是我的托管 bean：

enter code here
        @Scope("session")
        @Component("UtilisateurComponent")
        public class UtilisateurComponentImpl implements UtilisateurComponent {

        private Utilisateur utilisateur;
        byte[] f;
        private UploadedFile file;
        private StreamedContent content;
        @Autowired
        private UtilisateurDAO utilisateurDAO;
        @Autowired
        private UtilisateurService utilisateurService;
        public StreamedContent getContent() {
          FacesContext context = FacesContext.getCurrentInstance();

           if (context.getCurrentPhaseId() == PhaseId.RENDER_RESPONSE) {
                     return new DefaultStreamedContent();
                 }
           else{
            String imageId = context.getExternalContext().getRequestParameterMap().get("id");
           Utilisateur u = utilisateurDAO.findUtilisateurByIduser(Integer.parseInt(imageId));
           return new DefaultStreamedContent(new ByteArrayInputStream(u.getPhoto())); //the line that throw the Error 
           }
         }

     public void setContent(StreamedContent content) {
        this.content = content;
    }

    @PostConstruct
     public void init() {
         //initialize the data here
         this.utilisateur = new Utilisateur();

     }


     public UploadedFile getFile() {
         return file;
     }
     public void setFile(UploadedFile file) {
         this.file = file;
     }


       @Transactional
     public String saveUtilisateurTest(Utilisateur utilisateur) {
      try{

           utilisateur.setPhoto(getFile().getContents());

           utilisateurService.saveUtilisateur(utilisateur);
           file=null;

          }
          catch(Exception ex){
           ex.printStackTrace();
          }
         return "/jsf/utilisateur/listUtilisateurs.xhtml";

     }
     f = new byte[event.getFile().getContents().length];
      System.arraycopy(event.getFile().getContents(),0,f,0,event.getFile().getContents().length);

          FacesMessage message = new FacesMessage("Succesful", event.getFile().getFileName() + " is uploaded.");

          FacesContext.getCurrentInstance().addMessage(null, message);

     }
}

根据我的堆栈跟踪，

Grave: Error in streaming dynamic resource. Error reading 'content' on type $Proxy16
juin 17, 2014 10:56:03 PM org.apache.catalina.core.StandardWrapperValve invoke
Grave: "Servlet.service()" pour la servlet Faces Servlet a généré une exception
java.io.IOException: javax.el.ELException: Error reading 'content' on type $Proxy16
    at org.primefaces.application.PrimeResourceHandler.handleResourceRequest(PrimeResourceHandler.java:122)
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:306)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.primefaces.webapp.filter.FileUploadFilter.doFilter(FileUploadFilter.java:98)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.springframework.orm.jpa.support.OpenEntityManagerInViewFilter.doFilterInternal(OpenEntityManagerInViewFilter.java:113)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:315)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Caused by: javax.el.ELException: Error reading 'content' on type $Proxy16
    at javax.el.BeanELResolver.getValue(BeanELResolver.java:110)
    at javax.el.CompositeELResolver.getValue(CompositeELResolver.java:67)
    at com.sun.faces.el.FacesCompositeELResolver.getValue(FacesCompositeELResolver.java:71)
    at com.sun.el.parser.AstValue.getValue(AstValue.java:116)
    at com.sun.el.parser.AstValue.getValue(AstValue.java:163)
    at com.sun.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:219)
    at org.primefaces.application.PrimeResourceHandler.handleResourceRequest(PrimeResourceHandler.java:85)
    ... 27 more
Caused by: java.lang.NullPointerException
    at java.io.ByteArrayInputStream.<init>(Unknown Source)
    at com.gestion.projet.web.jsf.UtilisateurComponentImpl.getContent(UtilisateurComponentImpl.java:119)
    at sun.reflect.GeneratedMethodAccessor38.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)

(UtilisateurComponentImpl.java:119) 行注释在 managedbean Method 上

StreamedContent getMyContent()

Answer 1

return new DefaultStreamedContent(new ByteArrayInputStream(u.getPhoto()));

在上面的行中你是空的，问题是你没有从数据库中把他带回来或者你的imageId没有在bean中接收到。

你可以这样做

<p:graphicImage  value="#{UtilisateurComponent.getContent(current.iduser)}" height="100" width="150"/>

在你的函数中获取你的用户 ID

public StreamedContent getContent(Integer userId){...}

希望这会有所帮助

Answer 2

问题在于传递的参数，您有一个包含多行的数据表，然后您发送具有相同 ID 的参数。