如何在p：dataTable中使用p：graphicImage与StreamedContent？ [英] How to use p:graphicImage with StreamedContent within p:dataTable?
问题描述
< p：dataTable id =tablaInventariovar =invvalue =＃ {registrationrarPedidoController.inventarioList}paginator =truerows =10
selection =＃{registrarPedidoController.inventarioSelected}selectionMode =single
update =tablaInventario tablaDetalle total totalDescdblClickSelect = falsepaginatorPosition =bottom>
< p：column sortBy =producto.codigofilterBy =producto.codigo>
< f：facet name =header>＃{msg.codigo}< / f：facet>
＃{inv.producto.codProducto}
< / p：column>
< p：column>
< f：facet name =header> Foto< / f：facet>
< p：graphicImage id =photovalue =＃{registrarPedidoController.streamedImageById}cache =FALSE>
< f：param name =invvalue =＃{inv.id}/>
< / p：graphicImage>
< / p：column>
< / p：dataTable>
与
public StreamedContent getStreamedImageById（）{
DefaultStreamedContent image = null;
String get = FacesContext.getCurrentInstance（）。getExternalContext（）。getRequestParameterMap（）。get（inv）;
System.out.println（[Param]：+ get）; //打印null。
Long id = new Long（get）;
列表< Inventario> listInventarios = controladorRegistrarPedido.listInventarios（）;
（Inventario i：listInventarios）{
if（i.getId（）。compareTo（id）== 0）{
byte [] foto = i.getProducto ）.getFoto（）;
image = new DefaultStreamedContent（new ByteArrayInputStream（foto），image / png）;
}
}
return image;
}
但是我无法得到它的工作。我的参数是将null传递给我的支持bean。这是如何引起的，如何解决？
我正在使用Netbeans 6.9.1，JSF 2.0和Primefaces 2.2.RC2。
我继续使用BalusC第一个解决方案，它工作正常，但图像没有在UI中呈现。例外Glassfish正在抛出：
警告：StandardWrapperValve [Faces Servlet]：PWC1406：Servlet.service（）for servlet Faces Servlet throw异常
java.lang.NullPointerException
在com.sun.faces.mgbean.BeanManager $ ScopeManager $ ViewScopeHandler.isInScope（BeanManager.java:552）
好吧，我感谢BalusC的工作。我必须使用RequestScoped，SessionScoped或ApplicationScoped来管理getStreamedImageId。但是在UI中总是设置默认图像（对于空的情况），而不是像预期的每一行对应的图像。新代码是：
public StreamedContent streamedById（Long id）{
DefaultStreamedContent image = null;
System.out.println（[ID发明]：+ id）;
列表< Inventario> listInventarios = controladorRegistrarPedido.listInventarios（）;
for（Inventario i：listInventarios）{
if（i.getId（）。equals（id））{
byte [] foto = i.getProducto（）。getFoto（）;
if（foto！= null）{
System.out.println（[Foto]：+ foto）;
image = new DefaultStreamedContent（new ByteArrayInputStream（foto），image / png）;
break;
}
}
}
if（image == null）{
System.out.println（[Image null] ）;
byte [] foto = listInventarios.get（0）.getProducto（）。getFoto（）;
image = new DefaultStreamedContent（new ByteArrayInputStream（foto），image / png）;
}
System.out.println（[Foto Streamed]：+ image）;
返回图片;
}
code>< p：graphicImage> 将调用getter方法两次。首先是将< img> 元素呈现为HTML，因此需要 src 中的URL属性。如果你刚刚返回新的DefaultStreamedContent（），那么它会在 src 属性中自动生成正确的URL。第二次是当浏览器真正请求图像时，这是您应该返回实际图像的时刻。
所以，getter方法基本上应该是这样的： / p>
public StreamedContent getStreamedImageById（）{
FacesContext context = FacesContext.getCurrentInstance（）;
if（context.getCurrentPhaseId（）== PhaseId.RENDER_RESPONSE）{
//所以我们渲染视图。返回一个存根StreamedContent，以便它将生成正确的URL。
返回新的DefaultStreamedContent（）;
}
else {
//因此，浏览器正在请求图像。从实际请求参数获取ID值。
String id = context.getExternalContext（）。getRequestParameterMap（）。get（id）;
Image image = service.find（Long.valueOf（id））;
返回新的DefaultStreamedContent（新的ByteArrayInputStream（image.getBytes（）））;
}
}
I want to dynamically load images from a database withing a PrimeFaces data table. Code looks like as follows which is based on this PF forum topic:
<p:dataTable id="tablaInventario" var="inv" value="#{registrarPedidoController.inventarioList}" paginator="true" rows="10"
selection="#{registrarPedidoController.inventarioSelected}" selectionMode="single"
update="tablaInventario tablaDetalle total totalDesc" dblClickSelect="false" paginatorPosition="bottom">
<p:column sortBy="producto.codigo" filterBy="producto.codigo">
<f:facet name="header">#{msg.codigo}</f:facet>
#{inv.producto.codProducto}
</p:column>
<p:column>
<f:facet name="header">Foto</f:facet>
<p:graphicImage id="photo" value="#{registrarPedidoController.streamedImageById}" cache="FALSE">
<f:param name="inv" value="#{inv.id}" />
</p:graphicImage>
</p:column>
</p:dataTable>
with
public StreamedContent getStreamedImageById() {
DefaultStreamedContent image = null;
String get = FacesContext.getCurrentInstance().getExternalContext().getRequestParameterMap().get("inv");
System.out.println("[Param]: " + get); // This prints null.
Long id = new Long(get);
List<Inventario> listInventarios = controladorRegistrarPedido.listInventarios();
for (Inventario i : listInventarios) {
if (i.getId().compareTo(id) == 0) {
byte[] foto = i.getProducto().getFoto();
image = new DefaultStreamedContent(new ByteArrayInputStream(foto), "image/png");
}
}
return image;
}
However I can't get it work. My param is passing "null" to my backing bean. How is this caused and how can I solve it?
I am using Netbeans 6.9.1, JSF 2.0 and Primefaces 2.2.RC2.
I went on using BalusC first solution, it worked fine but images aren't being rendered in the UI. Exceptions Glassfish is throwing up:
WARNING: StandardWrapperValve[Faces Servlet]: PWC1406: Servlet.service() for servlet Faces Servlet threw exception
java.lang.NullPointerException
at com.sun.faces.mgbean.BeanManager$ScopeManager$ViewScopeHandler.isInScope(BeanManager.java:552)
Well seems I get working thanks to BalusC. I've to used RequestScoped, SessionScoped or ApplicationScoped for managing the getStreamedImageId. However in the UI is always setting the default image (for the null cases) and not as expected the image that correspondes to each row. The new code is:
public StreamedContent streamedById(Long id) {
DefaultStreamedContent image = null;
System.out.println("[ID inventario]: " + id);
List<Inventario> listInventarios = controladorRegistrarPedido.listInventarios();
for (Inventario i : listInventarios) {
if (i.getId().equals(id)) {
byte[] foto = i.getProducto().getFoto();
if (foto != null) {
System.out.println(" [Foto]: " + foto);
image = new DefaultStreamedContent(new ByteArrayInputStream(foto), "image/png");
break;
}
}
}
if (image == null) {
System.out.println(" [Image null]");
byte[] foto = listInventarios.get(0).getProducto().getFoto();
image = new DefaultStreamedContent(new ByteArrayInputStream(foto), "image/png");
}
System.out.println(" [Foto Streamed]: " + image);
return image;
}
The <p:graphicImage> will call the getter method twice. First time is when the <img> element is to be rendered to HTML and thus requires an URL in the src attribute. If you just return new DefaultStreamedContent(), then it will autogenerate the right URL in src attribute. Second time is when the browser really requests the image, this is the moment when you should return the actual image.
So, the getter method should basically look like this:
public StreamedContent getStreamedImageById() {
FacesContext context = FacesContext.getCurrentInstance();
if (context.getCurrentPhaseId() == PhaseId.RENDER_RESPONSE) {
// So, we're rendering the view. Return a stub StreamedContent so that it will generate right URL.
return new DefaultStreamedContent();
}
else {
// So, browser is requesting the image. Get ID value from actual request param.
String id = context.getExternalContext().getRequestParameterMap().get("id");
Image image = service.find(Long.valueOf(id));
return new DefaultStreamedContent(new ByteArrayInputStream(image.getBytes()));
}
}
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