如何在Java Applet中动态清除JRE缓存

Question

Here is code:

<applet code="ATest.class" archive="ATest.class?v=200406181300">
</applet>

I want to clear existing cache and load the new one when it loads 1st time.How can i do in java applet?

I tested it in Firefox 0.9 and it loaded and ran the class. The idea here is that when you change the class, you change the [v]ersion in the ARCHIVE attribute. That should force the browser to get a new copy of the class file, since the "archive" is now at a different URI, and since the "archive" is the .class file, it might work (unless the user agent disregards ARCHIVEs that are classes, which is entirely possible)

Answer 1

I don't think the applet can so this.

But I don't think it needs to either. If the changing the v parameter to a different value isn't sufficient to get the browser to request a new copy of the class, then put it into a JAR file and arrange that the JAR file's name changes each time you want to deploy a fresh version.

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I should note that forcing the browser to download a fresh copy of a class if it hasn't changed is a bad idea. It won't achieve anything useful. On the contrary, it will waste server and network resources, and it will make the page load slower.

Answer 2

First, read your question: Why would one update an Applet, "when it loads 1st time"? If you mean the second time, when the plugin tries to load it from its own cache, than just use a new codebase, maybe a new one for every visit/or.