AWT with JSP

> Anyone please tell me whether I can use AWT in

> jsp?

I dont know if you can run it in jsp, but you can put your AWT stuff in a class and access that from a jsp.

> f so does the client need to install JVM in his

> browser for the page

No, JSP runs on the server not on the client....

If you are trying to use AWT in JSP to develop a user interface, then forget it!!

I have used AWT features to manipulate images, i.e. data processing, but all your jsp server can return to the client is HTML / javaScript and files.

From a JSP you can only use AWT for BACK END / Server Side processing.

If you want to develop a GUI / user interface you will need to use an Applet.

angrycata at 2007-7-14 17:22:33 >

You can return a buffered image to the user in jsp.

You CANNOT return AWT controls, buttons, input boxes etc.

You can still achieve what you want by putting controls in HTML, and displaying the output from the buffered image.

You need to

1) Have a web form where users enter data

2) Get your jsp to retrieve these values and pass them to a class using AWT

3) The class returns the buffered image to your jsp

4) Your jsp streams the Image to the browser along with an HTML form containgin your controls.

When considering third party tools did you look at

http://www.jfree.org/jfreechart/

This is open source, so you can take one of these graphs and customise it if you need to, there is no way I would start writing my own classes to do this.

angrycata at 2007-7-14 17:22:33 >

There is no code in bold, comment which lines you mean.

I am afraid it has been 2 years since I did anything like this so Im not going to be much help!

In principle there does not seem to be anything wrong with what you are doing, I think you will get it working in the end!

Post back which section causes the problem....

angrycata at 2007-7-14 17:22:33 >

Thanks for ur reply

Chk out, i enclosed the code which is giving problem

in something like this

****************************INSERTING THIS CREATES PROBLEM******

*****************************CODE STARTS**************************

<%@ page language="java" %>

<%@ page import="java.io.OutputStream" %>

<%@ page import="java.awt.image.BufferedImage" %>

<%@ page import="java.awt.*" %>

<%@ page import="com.sun.image.codec.jpeg.*" %>

<%@ include file = "graphBG.jsp"%>

<%

//Data arrays

String datanames[] = {"Apples", "Oranges", "Peaches", "Lemons", "Grapefruit"};

int datavalues[] = {11, 62, 33, 102, 50};

//current y position

int y_pos = 0;

//y offset to cater for header space

int headerOffset = 50;

//inner padding to make sure bars never touch the outer border

int innerOffset = 20;

//height of bar, text and total

int barHeight = 10;

int textHeight = 20;

int displayHeight = barHeight + textHeight;

//Color used for the bars

Color barColor = new Color(153,19,19);

//Set the graph's outer width

int WIDTH = 300;

//Set the graph's outer height

int HEIGHT = (datavalues.length * displayHeight) + headerOffset + innerOffset;

//Width of the graphable area

int innerWIDTH = WIDTH - (innerOffset * 2);

//Calculate average

int average = 0;

for(int i=0; i<datavalues.length; i++)

{

average += datavalues;

}

average = average / datavalues.length;

//Calculate maximum

int maximum = 0;

for(int i=0; i<datavalues.length; i++)

{

if(datavalues > maximum)

{

maximum = datavalues;

}

}

///////////////////////////////////////////////////////////////////////////////////////

//Draw Graph Background and Header:

///////////////////////////////////////////////////////////////////////////////////////

response.setContentType("image/jpeg");

BufferedImage bi = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);

Graphics2D biContext = bi.createGraphics();

graphBG gr = new graphBG();

gr.draw(biContext, WIDTH, HEIGHT, "Farm Produce", "Overall Average: " + average);

/////////////////////////////////////////////////////////////////////////////////////

//Draw data onto the graph:

/////////////////////////////////////////////////////////////////////////////////////

//Loop through & draw the bars

for(int i=0; i<datavalues.length; i++)

{

int currentValue = datavalues;

//Set y position for bar

y_pos = i * displayHeight + headerOffset;

//Set bar width

int barWidth = (innerWIDTH * currentValue) / maximum;

//Display the current value

String display = datanames + " (" + currentValue + ")";

biContext.setColor(Color.black);

biContext.drawString(display, 20, y_pos);

//Set dimensions of the bar

biContext.setColor(barColor);

Dimension bar = new Dimension(barWidth , barHeight);

Dimension barBorder = new Dimension(barWidth - 3 , barHeight - 3);

Rectangle barRect = new Rectangle(bar);

Rectangle barRectBorder = new Rectangle(barBorder);

//Draw bar and border:

barRect.setLocation(21, 5 + y_pos);

barRectBorder.setLocation(22, 6 + y_pos);

biContext.setColor(barColor);

biContext.fill(barRect);

biContext.setColor(Color.white);

biContext.draw(barRectBorder);

}

%>

<html>

<body>

<TABLE border="1" cellpadding="0" cellspacing="0" height="100%" style="border-collapse: collapse" bordercolor="#111111" width="100%" id="AutoNumber1">

<tr>

******************************INSERTING THIS CREATES PROBLEM***********************

<td width='20%'>

<jsp:include page="a.jsp" flush="true" />

</td>

******************************INSERTING THIS CREATES PROBLEM******

<td width='80%'>

<%

/////////////////////////////////////////////////////////////////////////////////////

//Display the graph

/////////////////////////////////////////////////////////////////////////////////////

//Encode:

OutputStream output = response.getOutputStream();

JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(output);

encoder.encode(bi);

output.close();

%>

</td>

</tr>

</table>

</body>

</html>

The problem is that, Suppose I'm using something like

<INPUT TYPE=text name='aaa' value="">

This doesn't appear on the screen.

I suppose this cud be becoz

encoder.encode(bi) in the above code already opens a

PrintWriter stream which automatically disables the default JSP Printstream object (out).

I'm not sure about it.

Inputs from ur side can be of gr8 help to me.

Cheers,

Viswanath Kolli.

mouli_indiaa at 2007-7-14 17:22:33 >

Thank you very much.

It's working.

Right now I'm doing a project that display's trends of a company,

i mean their performance(revenue wise, resource utilization etc.)

I've never used AWT earlier.

Anyway thank u for ur help.

Cheers,

Viswanath Kolli

mouli_indiaa at 2007-7-14 17:22:33 >

Just , what ever code i showed u, i included that jsp as an image source in another jsp(suppose a.jsp).

Now in a.jsp i can write all the jsp code without any problem.

here's the code,for ur reference

Source File : a.jsp

*************CODE STARTS**************

<%@ page language="java" %>

<%@ page import="java.io.OutputStream" %>

<%@ page import="java.awt.image.BufferedImage" %>

<%@ page import="java.awt.*" %>

<%@ page import="java.sql.*" %>

<%@ page import="com.sun.image.codec.jpeg.*" %>

<html>

<body>

<TABLE border="1" cellpadding="0" cellspacing="0" height="100%" style="border-collapse: collapse" bordercolor="#111111" width="100%" id="AutoNumber1">

<tr>

<td width='15%'>

<input type=text name="aaa" value="">

</td>

<td width='85%' bgcolor="#90bade">

<img border="0" src="getImage.jsp">

</td>

</tr>

</table>

</body>

</html>

*************CODE ENDS**************

mouli_indiaa at 2007-7-14 17:22:33 >

Hi,

Is JfreeChart free for use or do we have buy it(i mean for corporate purposes)?.

It 's mentioned as free software on the site,but he explained the meaning of free as

"Free software is a matter of liberty, not price"

I have gone thru the site for details but I was unable to find where I can buy it (except the developer's guide).

Cheers

Viswanath Kolli

mouli_indiaa at 2007-7-21 9:07:11 >

Hey Kumar,

here is the code for ur reference.

********************CODE STARTS************************

<%!

public class graphBG

{

Font font = new Font("ARIAL", Font.BOLD , 11);

Color headerColor = new Color(20,50,100);

public Graphics2D draw(Graphics2D biContext, int WIDTH, int HEIGHT, String headerText, String averageText)

{

//Grey color for the drop shadow

Color dropShadow = new Color(200,200,200);

//Graph and header dimensions

Dimension dim = new Dimension(WIDTH,HEIGHT);

Dimension dimGraph = new Dimension(WIDTH-21,HEIGHT-51);

Dimension dimHeader = new Dimension(WIDTH-21,20);

//Define Rectangles:

Rectangle area = new Rectangle(dim);

Rectangle graphArea = new Rectangle(dimGraph);

Rectangle headerArea = new Rectangle(dimHeader);

/////////////////////////////////////////////////////////////////////////////////////

//Set up the graph:

/////////////////////////////////////////////////////////////////////////////////////

//Set background color to white:

biContext.setColor(Color.white);

biContext.fill(area);

//Drop shadow for the graph area:

graphArea.setLocation(18, 42);//This is the drop shadow's location

biContext.setColor(dropShadow);

biContext.fill(graphArea);

//Fill the graph area (white):

graphArea.setLocation(11, 36);

biContext.setColor(Color.white);

biContext.fill(graphArea);

//Draw the graph border (black):

biContext.setColor(Color.black);

biContext.draw(graphArea);

//Header Drop Shadow:

headerArea.setLocation(18, 12);//This is the drop shadow's location

biContext.setColor(dropShadow);

biContext.fill(headerArea);

//Fill the header (blue):

headerArea.setLocation(11, 5);

biContext.setColor(headerColor);

biContext.fill(headerArea);

//Draw the header border (white):

biContext.setColor(Color.white);

biContext.draw(headerArea);

//Insert Header Text:

biContext.setFont(font);

biContext.setColor(Color.white);

biContext.drawString(headerText, 21, 18);

//Display the average

biContext.setColor(Color.white);

biContext.drawString(averageText, 150, 18);

return biContext;

}

}

%>

Bye.

Cheers,

Viswanath Kolli.

********************CODE ENDS**************************

mouli_indiaa at 2007-7-21 9:07:11 >