Question

在将文件作为对REST请求的响应返回后，处理删除文件的最佳方法是什么？

我有一个端点，可以根据请求创建文件并在响应中返回它。一旦调度响应，就不再需要该文件，可以/应该删除该文件。

@Path("file")
@GET
@Produces({MediaType.APPLICATION_OCTET_STREAM})
@Override
public Response getFile() {

        // Create the file
        ...

        // Get the file as a steam for the entity
        File file = new File("the_new_file");

        ResponseBuilder response = Response.ok((Object) file);
        response.header("Content-Disposition", "attachment; filename=\"the_new_file\"");
        return response.build();

        // Obviously I can't do this but at this point I need to delete the file!

}

我想我可以创建一个tmp文件，但我认为有更优雅的机制来实现这一目标。该文件可能非常大，因此我无法将其加载到内存中。

Answer 1

将StreamingOutput用作实体：

final Path path;
...
return Response.ok().entity(new StreamingOutput() {
    @Override
    public void write(final OutputStream output) throws IOException, WebApplicationException {
        try {
            Files.copy(path, output);
        } finally {
            Files.delete(path);
        }
    }
}

Answer 2

有一个更优雅的解决方案，不写文件，只是直接写入Response实例中包含的输出流。

Answer 3

在不知道应用程序的上下文的情况下，您可以在VM退出时删除该文件：

file.deleteOnExit();

请参阅：https://docs.oracle.com/javase/7/docs/api/java/io/File.html#deleteOnExit%28%29

Answer 4

我最近在使用球衣的休息服务开发中做了类似的事情

@GET
@Produces("application/zip")
@Path("/export")
public Response exportRuleSet(@QueryParam("ids") final List<String> ids) {

    try {
        final File exportFile = serviceClass.method(ruleSetIds);

        final InputStream responseStream = new FileInputStream(exportFile);


        StreamingOutput output = new StreamingOutput() {
            @Override
            public void write(OutputStream out) throws IOException, WebApplicationException {  
                int length;
                byte[] buffer = new byte[1024];
                while((length = responseStream.read(buffer)) != -1) {
                    out.write(buffer, 0, length);
                }
                out.flush();
                responseStream.close();
               boolean isDeleted = exportFile.delete();
                log.info(exportFile.getCanonicalPath()+":File is deleted:"+ isDeleted);                 
            }   
        };
        return Response.ok(output).header("Content-Disposition", "attachment; filename=rulset-" + exportFile.getName()).build();
    }

Answer 5

将响应保存在tmp变量中，并替换return语句，如下所示：

Response res = response.build();
//DELETE your files here.
//maybe this is not the best way, at least it is a way.
return res;

Answer 6

在回复时发送文件名：

return response.header("filetodelete", FILE_OUT_PUT).build();

之后你可以发送删除restful方法

@POST
@Path("delete/{file}")
@Produces(MediaType.TEXT_PLAIN)
public void delete(@PathParam("file") String file) {

    File delete = new File(file);

    delete.delete();

}

REST响应后如何删除文件

6 个答案: