Is there any jar file available for uploading and downloading files in spring framework.Am searching for one to which we can pass our selected files then it can upload the files to server location.
Check out Spring's multipart (fileupload) support:
Spring has built-in multipart support to handle fileuploads in web applications. The design for the multipart support is done with pluggable MultipartResolver objects, defined in the org.springframework.web.multipart package. Out of the box, Spring provides a MultipartResolver for use with Commons FileUpload (http://jakarta.apache.org/commons/fileupload). How uploading files is supported will be described in the rest of this chapter.
It explains everything you need for file upload, hope that helps.
Related
Spring cloud-config-server has a built in mechanism to communicate with git repository and read files which are stored there. Then cloud-config-server also has built in mechanism to expose endpoints to clients (normally spring boot apps) which can read those files and use them as configurations.
This is well documented in spring documentation as can be seen from bellow.
According to doc
Spring Cloud Config Server
Spring Cloud Config Server provides an HTTP
resource-based API for external configuration (name-value pairs or
equivalent YAML content).
Also as documented about the serving format
Serving Alternative Formats
The default JSON format from the
environment endpoints is perfect for consumption by Spring
applications, because it maps directly onto the Environment
abstraction. If you prefer, you can consume the same data as YAML or
Java properties by adding a suffix (".yml", ".yaml" or ".properties")
to the resource path. This can be useful for consumption by
applications that do not care about the structure of the JSON
endpoints or the extra metadata they provide (for example, an
application that is not using Spring might benefit from the simplicity
of this approach).
It can also support txt format
Serving Plain Text
Instead of using the Environment abstraction (or
one of the alternative representations of it in YAML or properties
format), your applications might need generic plain-text configuration
files that are tailored to their environment.
But considering that spring cloud config server has the built in mechanism to communicate with a git repository and also exposes endpoints to the clients to consume the delivered files, it would make sense for other type of files to be able to be served from those endpoints as well.
It could be for example .pdf , .xslx , or even .zip
For example let's assume that the configured git repository contains the file myFile.zip in featureA branch. Then the call under the exposed path of type /{application}/{profile}[/{label}] for example as
serverUrl:serverPort/myApp/default/featureA/myFile.zip is able to deliver the file but is always delivered as raw .txt file which then corrupts the content of the original file existing in git.
I have already found the solution, but invested many hours on it and it was strange that it was not documented in spring documentation. So it is probably good to exist here as well to spare some time from others having the same issue.
As discussed under this issue, spring-cloud-config-server runs under the hood with the help of a normal spring-boot app. Considering that spring-boot has built in content negotiation mechanism it is able to consume and produce different content as well.
As for spring-cloud-config-server it is possible to fetch binary files from git as well as other files (ex zip, pdf, word, xlsx ...) if the call is made with the header Accept: application/octet-stream . This way the call to serverUrl:serverPort/myApp/default/featureA/myFile.zip is able to deliver a copy of the original file myFile.zip without any corruption.
I have spend lots of time to understand the internal working of a multipart file upload in spring boot.
Couldn't get a clear picture on it.
Bit confused about the role of spring boot tmp directory.
I have a tmp directory named as /tmp/tomcat.4296537502689403143.8587/work/Tomcat/localhost/ROOT]
I was checked the tmp directory during the file upload, couldn't write anything here.If i delete the folder it will throw multipart error.
Can anyone explain the internal working of a file upload and the role of tmp directory.
Spring boot web framework comes with embedded web servers: Tomcat by default. Tomcat creates/uses the tmp directory to store temporary files; including uploaded files, session files, and other files.
That behavior can be changed through configuration. Alternatively, you can also configure spring boot to use a different web server.
https://github.com/spring-projects/spring-boot/blob/70eee612ff2a2b1e58cbcb18a4d46e464895c18a/spring-boot/src/main/java/org/springframework/boot/context/embedded/tomcat/TomcatEmbeddedServletContainerFactory.java
It appears Tomcat is not handling parallel uploads of the same multipart file by two different users.
Test
Two sessions/users A & B
Both upload a 20MB file with the same name foo.pdf more or less at the same time
Servlet 3.0 Request with default configuration stores the two files in the tmp folder
Both threads try to write that foo.pdf into the tmp folder
Result
The uploaded document is corrupt (two streams writing to it)
The slower request will fail with a FileNotFoundException as the tmp file was already deleted by the cleanup task of the faster request.
Is there a way to avoid this - other than setting fileSizeThreshold higher than maxFileSize so it would never be written to disk in the first place.
Side note: this is a Spring Boot 2.1 application but this is irrelevant as it uses this Servlet 3.0 implementation by default.
I have an answer but it's not really satisfactory. We didn't figure out how to make this work with Tomcat's Servlet 3.0 implementation. However, once we switched to Apache commons-fileupload all was well.
So, for Spring (Boot) applications you would
set spring.servlet.multipart.enabled: false
configure a bean of type CommonsMultipartResolver with a name of multipartResolver
add the commons-fileupload dependency
My company uses Spring to provide RESTful service, But I can't find the log files as I usually do(from Tomcat/logs).All I can find is a jar file when Tomcat is built-in. So how can I find the log files?
Following Link will Help you Just check it
http://tutorialspoint.com/spring/logging_with_log4j.htm
I want to make an application is which file handling is used. That is file downloading (get the file), file parsing(process the file) and file uploading. It is not a web project. Actually the idea is we make this project and then make a jar of it and then use it in our further projects. How can i design my application so it is extendable easily in future. Is there is any spring framework for this task?
Thanks
I would suggest either Spring Batch or Apache Camel. These two frameworks can automate the downloading/uploading functionality you are after and let you define the file parsing in a well structured manner. If you are after csv or line-by-line parsing it's already done for you and you'll be at the file parsing bit just with a few configuration. Take a look at the Spring Batch sample examples and Apache Camel examples as a starting point.