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How can I paint a chart in the jsp
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Ning Du
Greenhorn
Joined: Jul 08, 2003
Posts: 11
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I want to paint a chart in the .jsp file using the data got from DataBase. How can I do that?
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SCJP1.4
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Ning Du
Greenhorn
Joined: Jul 08, 2003
Posts: 11
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When I make a binary file using servlet,the content of HTML cannot be displayed.What should I do? Applet? [ August 16, 2003: Message edited by: Adu Ning ]
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William Brogden
Author and all-around good cowpoke
Rancher
Joined: Mar 22, 2000
Posts: 12268
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Think about how a HTML page containing an image is built. Each chart or other image must be the result of a separate IMG tag that you write in your JSP. The SRC= attribute in the IMG tag should point to a servlet that can generate the binary image data. You can't use a JSP to generate typical image files because a JSP is designed to output text, not binary image data. There have been a number of discussions of this here. Any book on servlets will tell you how this is done. Bill
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Java Resources at www.wbrogden.com
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Ning Du
Greenhorn
Joined: Jul 08, 2003
Posts: 11
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William,thank you for your reply.Someone told me img=attribute tag poits to a .dll file can also solve the question.right?
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Ron Newman
Ranch Hand
Joined: Jun 06, 2002
Posts: 1056
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I don't understand what you mean by that.
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Ron Newman - SCJP 1.2 (100%, 7 August 2002)
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Chuck Kulchar
Greenhorn
Joined: Aug 11, 2003
Posts: 4
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I have my <img ...> tag point to a servlet which gets a chart using JFree chart (jfree.org), then uses a class included in the Jfree stuff that will display the image with the OutputStream. Display line is something like: ChartUtilities.writeChartAsJPEG(out,chart,820,380);
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William Brogden
Author and all-around good cowpoke
Rancher
Joined: Mar 22, 2000
Posts: 12268
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William,thank you for your reply.Someone told me img=attribute tag poits to a .dll file can also solve the question.right?
The IMG tag in HTML requires a SRC="URL" - the url is used to load the image data. That could be the URL of a servlet plus parameters that might include the name of a dll that is somehow involved. What image source do you want to use? Bill
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Ron Newman
Ranch Hand
Joined: Jun 06, 2002
Posts: 1056
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What is a "dll" ?
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Ning Du
Greenhorn
Joined: Jul 08, 2003
Posts: 11
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Something like :<IMG height="268" border="0" width="323" SRC="http://202.108.253.131:8080/wwwhq.dll?srv=401&...">
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Bear Bibeault
Author and ninkuma
Marshal
Joined: Jan 10, 2002
Posts: 56185
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I believe that a DLL can be used if it implements the ISAPI interface. This of course ties one into the Microsoft platform. Not a great idea, imho. bear
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[Smart Questions] [JSP FAQ] [Books by Bear] [Bear's FrontMan] [About Bear]
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subject: How can I paint a chart in the jsp
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