Home.... | log in.... | Pub my question! | Sign-up....

Java-index >> Enterprise & Remote Computing >> Web Tier APIs

display an object of Image type or Byte Array

Hi, lets say i got an image stored in the Image format or byte[]. How can i make it display the image on the screen by taking the values in byte array or Image field?

[173 byte] By [IronKnighta] at [2007-11-26 18:45:19]

«« Problem with carrying over an instantiated object to another file
»» Instances and References

# 1

>lets say i got an image stored in the Image

> format or byte[].

Alright

>How can i make it display the

> image on the screen by taking the values in byte

> array or Image field?

which screen ru talking about ? is it a servlet which you are refering to which displays Image Data ? if tht is the case... take a look of the example code which i have posted in the below thread.

http://forum.java.sun.com/thread.jspa?threadID=5137711&messageID=9504191#9504191

Hope this might help...

REGARDS,

RaHuL

RahulSharnaa at 2007-7-9 6:19:14 >

top of Java-index,Enterprise & Remote Computing,Web Tier APIs...

# 2

Thanks rahul,

The thing is, i am generating a chart in a servlet and setting the image in the form of a byte [] to the view bean ( which is binded to the jsp, springs framework ). The servlet would return the view bean to the jsp and in the jsp, i am suppose to print this byte array so as to give me the image..

I hope this makes sense.. pls help me ou!

IronKnighta at 2007-7-9 6:19:14 >

# 3

> Thanks rahul,

> The thing is, i am generating a chart in a servlet

> and setting the image in the form of a byte [] to the

> view bean ( which is binded to the jsp, springs

> framework ). The servlet would return the view bean

> to the jsp and in the jsp, i am suppose to print this

> byte array so as to give me the image..

> I hope this makes sense.. pls help me ou!

Well letme see if i got tht right or not,

you are trying to call Your MODEL (Business layer / Spring Container) from a servlet and you are expressing that logic in form of chart (Image) and trying to save it as a byte array in a view bean and you want to print /display that as an image in a jsp (After Servlet fwd / redirect action) which includes other data using a ViewBean.

If this is the case...

As the forwaded JSP can include both image and Textual (hypertext too)..we can try a work around hear...Lets dedicate a Servlet which retreives byte [] from a view bean and gives us an image output. hear is an example and this could be a way.

Prior to that i'm trying to make few assumptions here....

1).The chart image which we are trying to express would of format JPEG.

2).we are trying to take help of<img> tag to display the image from the image generating servlet.

here is my approach....

ViewBean.java:

============

public class ViewBean implements serializable{

byte piechart[];

byte barchart[];

byte chart3D[];

public ViewBean(){

}

public byte[] getPieChart(){

return(this.piechart);

}

public byte[] getBarChart(){

return(this.barchart);

}

public byte[] get3DChart(){

return(this.chart3D);

}

public void setPieChart(byte piechart[]){

this.piechart = piechart;

}

public void setBarChart(byte barchart[]){

this.barchart = barchart;

}

public void set3DChart(byte chart3D[]){

this.chart3D = chart3D;

}

ControllerServlet.java:

=================

(This could also be an ActionClass(Ref Struts) a Backing Bean(Ref JSF) or anything which stays at the Controller Layer)

public void doGet(HttpServletRequest request,HttpServletResponse response) throws IOException{

/* There are few different implementations of gettingBeanFactory Resource

In,the below example i have used XmlBeanFactory Object to create an instance of (Spring) BeanFactory */

BeanFactory factory =

new XmlBeanFactory(new FileInputStream("SpringResource.xml"));

//write a Util Logic in your Implementation class using JFreeChart (or some open source chart library) and express the images by returning a byte[]

ChartService chartService =

(GreetingService) factory.getBean("chartService");

ViewBean vb = new ViewBean();

vb.setPieChart(chartService.generatePieChart(request.getParameter("<someparam>"));

vb.setBarChart(chartService.generateBarChart(request.getParameter("<someparam1>"));

vb.set3DChart(chartService.generate3DChart(request.getParameter("<someparam2>"));

chartService = null;

HttpSession session = request.getSession(false);

session.setAttribute("ViewBean",vb);

response.sendRedirect("jsp/DisplayReports.jsp");

}

DisplayReports.jsp :

================

<%@ page language="java" %>

<html>

<head>

<title>reports</title>

</head>

<body>

<h1 align="center">Pie Chart </h1>

<h1 align="center">Bar Chart </h1>

<h1 align="center">3D Chart</h1>

</body>

</html>

ImageServlet.java

==============

public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException

{

byte buffer[];

HttpSession session = request.getSession(false);

ViewBean vb = (ViewBean) session.getAttribute("ViewBean");

String req = request.getParameter("req");

if(req.equals("1") == true)

buffer = vb.getPieChart();

else if(req.equals("2") == true)

buffer = vb.getBarChart();

else if(req.equals("3") == true)

buffer = vb.get3DChart();

JPEGImageDecoder decoder = JPEGCodec.createJPEGDecoder(new ByteArrayInputStream(buffer));

BufferedImage image =decoder.decodeAsBufferedImage() ;

response.setContentType("image/jpeg");

// Send back image

ServletOutputStream sos = response.getOutputStream();

JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(sos);

encoder.encode(image);

}

Note: Through ImageServlet is a Servlet i would categorise it under presentation layer rather to be a part of Controller and added to it all this could be easily relaced by a reporting(BI) server like JasperServer,Pentaho,Actuate................

Hope the stated implementation had given some idea to you....

However,If you want to further look into similar implementations take a look at

http://www.swiftchart.com/exampleapp.htm#e5

which i believe to be a wonderful tutor for such implementations...

However, there are many simple (Open) solutions to the stated problem.. if you are Using MyFaces along with spring... i would recommend usage of JSF Chart Tag which is very simple to use all it requires need is to write a chart Object generating methos inside our backing bean.

For further reference have a look at the below links

http://www.jroller.com/page/cagataycivici?entry=acegi_jsf_components_hit_the

http://jsf-comp.sourceforge.net/components/chartcreator/index.html

NOTE:I've tried it personally using MyFaces it was working gr8 but i had a hardtime on deploying my appln on a Portal Server(Liferay).If you find a workaround i'd be glad to know about it.

& there are many BI Open Source Server Appls that can take care of this work too.(Maintainace wud be a tough ask when we go for this)

For, the design perspective had i've been ur PM i wud have choose BI Server if it was corporate web appln on which we work on.

Hope this might be of some help :)

REGARDS,

RaHuL

RahulSharnaa at 2007-7-9 6:19:14 >

# 4

Wow.. thanks a lot rahul for talking time to reply back.. I should I have replied back then.. but was stuck with something else.. I tried it the same way that u have suggested..it worked :)

IronKnighta at 2007-7-9 6:19:14 >

# 5

Oh! Cul (How abt my duke dollars then)

RahulSharnaa at 2007-7-9 6:19:14 >

Java programming resources: FAQs, tutorials, compiler and browser download sites, documentation, books lists, IDEs, etc.

display an object of Image type or Byte Array

Enterprise & Remote Computing New Topic

Enterprise & Remote Computing Hot Topic

Enterprise & Remote Computing

All Classified