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package org.primefaces.component.filedownload;
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import java.io.IOException;
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import javax.el.ELContext;
import javax.el.ValueExpression;
import javax.faces.component.StateHolder;
import javax.faces.context.FacesContext;
import javax.faces.event.AbortProcessingException;
import javax.faces.event.ActionEvent;
import javax.faces.event.ActionListener;
import javax.servlet.http.HttpServletResponse;
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import org.primefaces.model.StreamedContent;
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public class FileDownloadActionListener implements ActionListener, StateHolder {
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private ValueExpression value;
private ValueExpression contentDisposition;
public FileDownloadActionListener() {}
public FileDownloadActionListener(ValueExpression value, ValueExpression contentDisposition) {
this.value = value;
this.contentDisposition = contentDisposition;
}
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public void processAction(ActionEvent actionEvent) throws AbortProcessingException {
FacesContext facesContext = FacesContext.getCurrentInstance();
ELContext elContext = facesContext.getELContext();
HttpServletResponse response = (HttpServletResponse) facesContext.getExternalContext().getResponse();
String contentDispositionValue = contentDisposition != null ? (String) contentDisposition.getValue(elContext) : "attachment";
StreamedContent content = (StreamedContent) value.getValue(elContext);
try {
? ?String fileName = java.net.URLEncoder.encode(content.getName(), "UTF-8");?
? ?response.setCharacterEncoding("UTF-8");
response.setContentType(content.getContentType());
response.setHeader("Content-Disposition", contentDispositionValue + ";filename=" + fileName);
byte[] buffer = new byte[2048];
int length;
while ((length = (content.getStream().read(buffer))) >= 0) {
response.getOutputStream().write(buffer, 0, length);
}
response.setStatus(200);
content.getStream().close();
response.getOutputStream().flush();
facesContext.responseComplete();
}catch (IOException e) {
e.printStackTrace();
}
}
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public boolean isTransient() {
return false;
}
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public void restoreState(FacesContext facesContext, Object state) {
Object values[] = (Object[]) state;
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value = (ValueExpression) values[0];
contentDisposition = (ValueExpression) values[1];
}
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public Object saveState(FacesContext facesContext) {
Object values[] = new Object[2];
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values[0] = value;
values[1] = contentDisposition;
return ((Object[]) values);
}
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public void setTransient(boolean value) {
}
}
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jsf源码:
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<table style="width:93%;margin:6px 0px 6px 0px;">
<tr>
<td>
<p:dataTable value="#{fileUploadAction.sfId}" var="fileUpLoad" id="fileID" emptyMessage="没有文件!">?
? ?
? ?<p:columnGroup type="header">
<p:row>
<p:column headerText="文件名称" />
<p:column headerText="下载文件" />
<p:column headerText="移除文件" />
</p:row>
</p:columnGroup>
? ?<p:column>
<h:outputText value="#{fileUpLoad.fName}" title="文件名称"/>
</p:column>
<p:column>
<h:commandLink title="下载文件" action="#{fileUploadAction.downloadFile(fileUpLoad.fId)}">
<p:graphicImage value="/images/download.gif" />
</h:commandLink>
</p:column>
? ?<p:column>
<h:commandLink ?ajax="true" title="移除文件" actionListener="#{fileUploadAction.doDeleteFile}" update="fileID">
<p:graphicImage value="/images/delete.png" />
<f:param name="fId" value="#{fileUpLoad.fId}" />
</h:commandLink>
</p:column>
?</p:dataTable>
?</td>
</tr>
<tr>
<td>
<p:fileUpload widgetVar="uploader" customUI="true" ?image="/images/browse.png" title="上传文件" height="48" width="48" fileUploadListener="#{fileUploadAction.doHandleFileUpload}" mode="advanced"
update="fileID" multiple="true" sizeLimit="1000000">
</p:fileUpload>
<p:commandButton value="文件上传" title="文件上传" onclick="uploader.upload();"?
style="font-weight:bold;color:#616D7E">
</p:commandButton>
</td>
</tr>
</table>