Image and Binary File Conversion

DWR 3.0 features a new FileConverter that handles the following binary files:

In order for upload to work, commons-fileupload and commons-io are required on the classpath. See the commons-upload dependency chart for more information. DWR will give you the error message: "file uploads not supported" if this JAR file is missing.

Specifying a max upload size

If you would like to limit the maximum allowed size of file uploads we provide the "fileUploadMaxBytes" init-param on the DWR servlet. This parameter can be specified as follows: 
     <init-param>
      <param-name>fileUploadMaxBytes</param-name>
      <param-value>5000</param-value>
     </init-param>

Plugging in a custom Upload implementation

The FileUpload implementation used by DWR is also pluggable. If you would like to write your own implementation simply implement org.directwebremoting.dwrp.FileUpload and use DWR's plug-in architecture to specify the implementation via an init-param on the DWR servlet. 
    <init-param>
     <param-name>org.directwebremoting.dwrp.FileUpload</param-name>
     <param-value>your.package.YourFileUploadImpl</param-value>
    </init-param>

Examples in the DWR.war

The DWR war file contains a number of examples of generating PDF files, as well as uploading and downloading images. Full source and explanations are included with these examples.