Question

当我要保存上传的图片时，我正在Stream is closed Exception。我想在保存之前预览上传图片的graphicImage。此操作正在运行。但我无法保存图像。这是我的代码：

private InputStream in;
private StreamedContent filePreview;
// getters and setters

public void upload(FileUploadEvent event)throws IOException { 
    // Folder Creation for upload and Download
    File folderForUpload = new File(destination);//for Windows
    folderForUpload.mkdir();
    file = new File(event.getFile().getFileName());
    in = event.getFile().getInputstream();
    filePreview = new DefaultStreamedContent(in,"image/jpeg");
    FacesMessage msg = new FacesMessage("Success! ", event.getFile().getFileName() + " is uploaded.");  
    FacesContext.getCurrentInstance().addMessage(null, msg);
}

public void setFilePreview(StreamedContent fileDownload) {
    this.filePreview = fileDownload;
}

public StreamedContent getFilePreview() {
    return filePreview;
}

public void saveCompanyController()throws IOException{
    OutputStream out  = new FileOutputStream(getFile());
    byte buf[] = new byte[1024];
    int len;
    while ((len = in.read(buf)) > 0)
        out.write(buf, 0, len);
    FileMasterDO fileMasterDO=new FileMasterDO();
    fileMasterDO.setFileName(getFile().getName());
    fileMasterDO.setFilePath(destination +file.getName());
    fileMasterDO.setUserMasterDO(userMasterService.findUserId(UserBean.getUserId()));
    fileMasterDO.setUpdateTimeStamp(new Date());
    in.close();
    out.flush();
    out.close();
    fileMasterService.save(filemaster);
}

bean在会话范围内。

Answer 1

您尝试读取InputStream两次（第一次是在DefaultStreamedContent上传方法的构造函数中，第二次是在save方法的复制循环中）。这是不可能的。它只能读一次。您需要先将其读入byte[]，然后将其指定为bean属性，以便可以将其重用于StreamedContent和保存。

确保永远保留外部资源，例如InputStream或OutputStream作为bean属性。从适用的当前和其他bean中删除它们，并使用byte[]将图像的内容保存为属性。

在您的特定情况下，您需要按如下方式修复它：

private byte[] bytes; // No getter+setter!
private StreamedContent filePreview; // Getter only.

public void upload(FileUploadEvent event) throws IOException {
    InputStream input = event.getFile().getInputStream();

    try {
        IOUtils.read(input, bytes);
    } finally {
        IOUtils.closeQuietly(input);
    }

    filePreview = new DefaultStreamedContent(new ByteArrayInputStream(bytes), "image/jpeg");
    // ...
}

public void saveCompanyController() throws IOException {
    OutputStream output = new FileOutputStream(getFile());

    try {
        IOUtils.write(bytes, output);
    } finally {
        IOUtils.closeQuietly(output);
    }

    // ...
}

注意：IOUtils来自Apache Commons IO，您应该已经在类路径中拥有它，因为它是<p:fileUpload>的依赖项。

流关闭异常

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