Download jakarta-jstl1. Download jakarta-oro Download jakarta-oro. Download jakarta-poi Download jakarta-regexp Download jakarta-regexp. Download jakarta-slide-ant-webdav Download jakarta-slide-commandline Download jakarta-slide-webdav. Download jakarta-slide-webdavlib Download jakarta-slide-webdavlib. Download jakarta-taglibs-core Download jakarta-taglibs-standard Download jakarta-tomcat Download jakarta-tomcat-bootstrap Download jakarta-tomcat-coyote Download jakarta-tomcat-http Download jakarta-tomcat-jni Download jakarta-tomcat-naming-common Download jakarta-tomcat-naming-factory Servlet Upload File and Download File is a common task in java web application.
Since I have written a lot about java servlet recently, I thought to provide a sample example of servlet file upload to server and then download from server to client. Our use case is to provide a simple HTML page where client can select a local file to be uploaded to server.
On submission of request to upload the file, our servlet program will upload the file into a directory in the server and then provide the URL through which user can download the file. For security reason, user will not be provided direct URL for downloading the file, rather they will be given a link to download the file and our servlet will process the request and send the file to user.
We will create a dynamic web project in Eclipse and the project structure will look like below image. We can upload a file to server by sending a post request to servlet and submitting the form. To select a file from user file system, we need to use input element with type as file. We need to store file into some directory at server, we can have this directory hardcoded in program but for better flexibility, we will keep it configurable in deployment descriptor context params.
Also we will add our upload file html page to the welcome file list. Since we need to read context parameter for file location and create a File object from it, we can write a ServletContextListener to do it when context is initialized.
We can set absolute directory location and File object as context attribute to be used by other servlets. Please check out Servlet 3 Upload File. For File upload, we will use Apache Commons FileUpload utility, for our project we are using version 1.
FileItem provides useful method to get the file name, field name in form, size and content type details of the file that needs to be uploaded. To write file to a directory, all we need to do it create a File object and pass it as argument to FileItem write method. Since the whole purpose of the servlet is to upload file, we will override init method to initialise the DiskFileItemFactory object instance of the servlet.
We will use this object in the doPost method implementation to upload file to server directory. Once the file gets uploaded successfully, we will send response to client with URL to download the file, since HTML links use GET method,we will append the parameter for file name in the URL and we can utilise the same servlet doGet method to implement file download process.
For implementing download file servlet, first we will open the InputStream for the file and use ServletContext. We will also need to set the response content length as length of the file. Once we are done with setting response configuration, we can read file content from InputStream and write it to ServletOutputStream and the flush the output to client. Httpservletresponse Download File Servlet Download Zip File Example Servlet Download File Example The example below is a servlet that shows you how to create a zip file and send the generated zip file for user to download.
Httpservletresponse Download File Search Download servlet-api. Related examples in the same category 1. Download servlet Download servlet-examples-jetty
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