JSF2.0如何下载文件

1. 直接使用文件链接

<h:outputLinkvalue="#{request.contextPath}/resources/file/hello.pdf">   

      <h:graphicImagelibrary="images"name="pdf.jpg"style="border:none"/>

</h:outputLink>

2.使用stream

@ManagedBean
@RequestScoped
public class FileDownLoadBean {
    public void down() throws IOException {
        File file = new File("/home/sunjingchuan/Desktop/helloCoco.txt");
        InputStream fis = new FileInputStream(file);

        FacesContext fc = FacesContext.getCurrentInstance();
        ExternalContext ec = fc.getExternalContext();
        ec.responseReset();
        ec.setResponseContentType("application/octet-stream");
        ec.setResponseContentLength((int)file.length());
        ec.setResponseHeader("Content-Disposition", "attachment; filename=helloCoco.txt");
        OutputStream output = ec.getResponseOutputStream();

        byte[] buffer = new byte[1024];
        int len = -1;
        while ((len = fis.read(buffer)) != -1) {
            output.write(buffer, 0, len);
        }

        fis.close();
        output.close();

        fc.responseComplete();
    }
}

页面可使用<h:commandLink>或<h:commandButton>

<h:commandLink value="download file" action="#{fileDownLoadBean.down}" />