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我有字符串路径，用于在标题上显示图像，我从数据库中获取返回图像字符串文件名的路径，然后图像位于“D:\Job\Potapota\images\(filename)”中。我已经在 a.setValue(dao.getLogos()); 上初始化了来自 db 的 String 路径。这意味着如果我只想像 a.getValue() 那样获取文件名。

所以这是我的 html 页面

<p:graphicImage value="#{fileUploadViewBean.imageStatus}" library="atlantis-layout"/>

那么 FileUploadViewBean 类就是这个

public class FileUploadViewBean extends CommonBean {

private StreamedContent imageStatus;
public void init() throws IOException{
    getLogo();
}

public StreamedContent getImageStatus() {
    return imageStatus;
}

public void setImageStatus(StreamedContent imageStatus) {
    this.imageStatus = imageStatus;
}

public void getLogo() throws IOException {
    SystemMaster a = new SystemMaster();
    FacesContext context = FacesContext.getCurrentInstance();
    try {
        a.setValue(dao.getLogos());
    } catch (Exception e) {
        setMessage(new FacesMessage(e.getMessage()));
        getMessage().setSeverity(FacesMessage.SEVERITY_FATAL);
        FacesContext.getCurrentInstance().addMessage(null, getMessage());
    }
    if (context.getCurrentPhaseId() == PhaseId.RENDER_RESPONSE) {
        // So, we're rendering the view. Return a stub StreamedContent so
        // that it will generate right URL.
        imageStatus = new DefaultStreamedContent();
    } else {
        // So, browser is requesting the image. Return a real
        // StreamedContent with the image bytes.
        String filename = 
context.getExternalContext().getRequestParameterMap().get(a.getValue());
        imageStatus = new DefaultStreamedContent(
                new FileInputStream(new File("D:\\Job\\Potapota\\images\\", 
        filename)), "image/jpeg");
    }
}

但是随后图像没有显示出来，有人可以知道什么是真正的代码。

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