Java Applet Writes to a Local File

Here's an applet that tries to write to a file on a local directory.

You must have a policy file to give this Applet (digital signed Applet) access to your local file system. This web page is part of a tutorial to demonstrate a Proof of Concept (prototype) of how a Java Applet can write to a local file. See the other pages for a full description.

Java Console: Open up the Java console. Messages are written there.

Using JavaScript with Java Plug-in: (works w/IE)

• Click here to run a debugTesting() method in the applet. (Applet embeded in Java Plugin)
• Click here to have JavaScript write to a local file. (note: Key to make this work is the parm value: param name = "scriptable" with value = "true" )
• Click here to have JavaScript read the local file and display in an alert box.
• Click here to have JavaScript run getDebugProperties().

Using JavaScript with Java (no Plug-in)

• Click here to run a debugTesting() method in the applet. (Applet not embeded.)
• Will create a security error: Click here to have JavaScript write to a local file. (note: Key to make this work is the parm value: param name = "scriptable" with value = "true" )
• Will create a security erorr: Click here to have JavaScript read the local file and display in an alert box.
• Click here to have JavaScript run getDebugProperties().

Access System Properties from Java:

• <NAME="scriptable" VALUE="true"> - This allows JavaScript to access the applet embeded in the Plug-in.
• <NAME="filename" VALUE="MyAppletWriteFile.txt"> - Name of the file created. Default is "MyAppletWriteFile.txt"
• <NAME="pathname" VALUE="c:/temp/"> - Path of the new file that is created. Default is comes from the user.home System Property unless specified as in this example.
• <NAME="debug" VALUE="true"> - This will automatically create a file with a default message. Also writes info to the Java Console.
• <NAME="debugmsg" VALUE="Hello from an Applet."> - Message that will be saved in the file.
  
• <NAME="debugproperties" VALUE="true"> - This will call getDebugProperites which will tell you System Properties. The default directory is user.home.