如何保存上传的文件在JSF中 [英] How to save uploaded file in JSF

问题描述

我正在上传一个JSF文件。我为此使用了Tomahawk的< t：inputFileUpload> ，但同样的问题也适用于例如。 PrimeFaces < p：fileUpload> 和JSF 2.2 < h：inputFile> 。 b

我有下面的支持bean代码：

pre $ private $ UploadedFile uploadedFile; // + getter + setter
$ b $ public String save（）throws IOException {
String name = uploadedFile.getName（）;
System.out.println（File name：+ name）;

String type = uploadedFile.getContentType（）;
System.out.println（File type：+ type）;

long size = uploadedFile.getSize（）;
System.out.println（File size：+ size）;

InputStream stream = uploadedFile.getInputStream（）;
byte [] buffer = new byte [（int）size];
stream.read（buffer，0，（int）size）;
stream.close（）;



$ b我可以得到文件名，类型和大小，但是我无法保存此文件在特定的路径。我无法弄清楚保存上传文件的正确方法。如何才能达到这个目的？

解决方案 上传的文件代表文件内容。

  InputStream input = uploadedFile.getInputStream（）; 
  

您需要将其复制到一个文件中。您应该先在本地磁盘文件系统上准备一个文件夹，上传的文件应该存储在该文件夹中。例如， / path / to / uploads （在Windows上，与服务器运行在同一个磁盘上）。请注意，由于在此提及的原因，绝对不 通过使用相对路径或 getRealPath（）将文件存储在展开的WAR文件夹中上传的图片只有刷新页面后才可用。

然后，您需要自动生成文件名。否则，当其他人稍后上传一个同名的文件时，它将被覆盖。您可以使用 Files＃createTempFile（） 设施获得一个自动生成的文件名。

  Path folder = Paths.get（/ path / to / uploads）; 
 String filename = FilenameUtils.getBaseName（uploadedFile.getName（））; 
字符串扩展= FilenameUtils.getExtension（uploadedFile.getName（））; 
路径文件= Files.createTempFile（文件夹，文件名+ - ，。+扩展名）; 
  

如果需要，上传路径可以根据本Q& A ：将上传的文件保存在servlet应用程序中的推荐方法。 FilenameUtils 是Apache Commons IO的一部分，因为它是Tomahawk文件上传组件的依赖关系，所以您应该已经在您的类路径中拥有了它们。

最后，将上传的文件流式传输到该文件中（假设Java 7）：
$ b $ $ p $ try（InputStream input = uploadedFile.getInputStream（））{
Files.copy（输入，文件，StandardCopyOption.REPLACE_EXISTING）;


System.out.println（上传的文件成功保存在+文件中）;


然后下载它，最简单的方法是注册 / path /将/ uploads 作为新的Web应用程序上下文或虚拟主机，以便所有这些文件都可以通过URL访问。另请参阅使用webapps / webcontext / deploy文件夹外部的图像< H：graphicImage的>或< img>标记。

I am uploading a file in JSF. I am using Tomahawk's <t:inputFileUpload> for this, but the same question is applicable on e.g. PrimeFaces <p:fileUpload> and JSF 2.2 <h:inputFile>.

I have the below backing bean code:

private UploadedFile uploadedFile; // +getter+setter

public String save() throws IOException {
    String name = uploadedFile.getName();
    System.out.println("File name: " + name);

    String type = uploadedFile.getContentType();
    System.out.println("File type: " + type);

    long size = uploadedFile.getSize();
    System.out.println("File size: " + size);  

    InputStream stream = uploadedFile.getInputStream();
    byte[] buffer = new byte[(int) size];  
    stream.read(buffer, 0, (int) size);  
    stream.close();  
}

I am able to get the file name, type and size, but I am unable to save this file at a specific path. I can't figure out the proper way to save the uploaded file. How can I achieve this?

解决方案

The getInputStream() method of the uploaded file represents the file content.

InputStream input = uploadedFile.getInputStream();

You need to copy it to a file. You should first prepare a folder on the local disk file system where the uploaded files should be stored. For example, /path/to/uploads (on Windows, that would be on the same disk as where the server runs). Note that you should absolutely not store the files in expanded WAR folder by using a relative path or getRealPath() for the reasons mentioned here Uploaded image only available after refreshing the page.

Then, you need to autogenerate the filename. Otherwise, when someone else uploads a file with coincidentally the same name later, it would be overwritten. You could use Files#createTempFile() facility to get an autogenerated filename.

Path folder = Paths.get("/path/to/uploads");
String filename = FilenameUtils.getBaseName(uploadedFile.getName()); 
String extension = FilenameUtils.getExtension(uploadedFile.getName());
Path file = Files.createTempFile(folder, filename + "-", "." + extension);

The path to uploads could if necessary be parameterized based on one of several ways shown in this Q&A: Recommended way to save uploaded files in a servlet application. The FilenameUtils is part of Apache Commons IO which you should already have in your classpath as it's a dependency of the Tomahawk file upload component.

Finally, just stream the uploaded file to that file (assuming Java 7):

try (InputStream input = uploadedFile.getInputStream()) {
    Files.copy(input, file, StandardCopyOption.REPLACE_EXISTING);
}

System.out.println("Uploaded file successfully saved in " + file);

Then, to download it back, easiest would be to register /path/to/uploads as a new webapp context or a virtual host so that all those files are available by an URL. See also Load images from outside of webapps / webcontext / deploy folder using <h:graphicImage> or <img> tag.

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