Generating a JPEG image and creating the image from a database query

Java draw graph
http://www.java2s.com/Code/Java/Servlets/ServlettodrawaGraphicalChartinresponsetoauserrequest.htm

/* -------------------
* LineChartDemo1.java
* -------------------
* (C) Copyright 2002-2005, by Object Refinery Limited.
*
*/
package demo;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import javax.swing.JPanel;
 
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.axis.NumberAxis;
import org.jfree.chart.plot.CategoryPlot;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.renderer.category.LineAndShapeRenderer;
import org.jfree.chart.title.TextTitle;
import org.jfree.data.category.CategoryDataset;
import org.jfree.data.category.DefaultCategoryDataset;
import org.jfree.ui.ApplicationFrame;
import org.jfree.ui.HorizontalAlignment;
import org.jfree.ui.RectangleEdge;
import org.jfree.ui.RefineryUtilities;

/**
* A simple demonstration application showing how to create a line chart using
* data from a {@link CategoryDataset}.
*/
public class LineChartDemo1 extends ApplicationFrame {
/**
* Creates a new demo.
*
* @param title the frame title.
*/
public LineChartDemo1(String title) {
super(title);
 
CategoryDataset dataset = createDataset();
JFreeChart chart = createChart(dataset);
ChartPanel chartPanel = new ChartPanel(chart);
chartPanel.setPreferredSize(new Dimension(500, 270));
setContentPane(chartPanel);
}
/**
* Creates a sample dataset.
*
* @return The dataset.
*/
private static CategoryDataset createDataset() {
DefaultCategoryDataset dataset = new DefaultCategoryDataset();
dataset.addValue(212, "Classes", "JDK 1.0");
dataset.addValue(504, "Classes", "JDK 1.1");
dataset.addValue(1520, "Classes", "SDK 1.2");
dataset.addValue(1842, "Classes", "SDK 1.3");
dataset.addValue(2991, "Classes", "SDK 1.4");
return dataset;
}

/**
* Creates a sample chart.
*
* @param dataset a dataset.
*
* @return The chart.
*/
private static JFreeChart createChart(CategoryDataset dataset) {
// create the chart...
JFreeChart chart = ChartFactory.createLineChart(
"Java Standard Class Library",
// chart title
"Release",
// domain axis label
"Class Count",
// range axis label
dataset,
// data
PlotOrientation.VERTICAL,
// orientation
false,
// include legend
true,
// tooltips
false
// urls
);
chart.addSubtitle(new TextTitle("Number of Classes By Release"));
TextTitle source = new TextTitle(
"Source: Java In A Nutshell (4th Edition) "
+ "by David Flanagan (O’Reilly)"
);
source.setFont(new Font("SansSerif", Font.PLAIN, 10));
source.setPosition(RectangleEdge.BOTTOM);
source.setHorizontalAlignment(HorizontalAlignment.RIGHT);
chart.addSubtitle(source);
chart.setBackgroundPaint(Color.white);
CategoryPlot plot = (CategoryPlot) chart.getPlot();
plot.setBackgroundPaint(Color.lightGray);
plot.setRangeGridlinePaint(Color.white);
// customise the range axis...
NumberAxis rangeAxis = (NumberAxis) plot.getRangeAxis();
rangeAxis.setStandardTickUnits(NumberAxis.createIntegerTickUnits());
// customise the renderer...
LineAndShapeRenderer renderer
= (LineAndShapeRenderer) plot.getRenderer();
renderer.setShapesVisible(true);
renderer.setDrawOutlines(true);
renderer.setUseFillPaint(true);
renderer.setFillPaint(Color.white);
return chart;
}
/**
* Creates a panel for the demo (used by SuperDemo.java).
*
* @return A panel.
*/
public static JPanel createDemoPanel() {
JFreeChart chart = createChart(createDataset());
 
 
return new ChartPanel(chart);
}
/**
* Starting point for the demonstration application.
*
* @param args ignored.
*/
public static void main(String[] args) {
LineChartDemo1 demo = new LineChartDemo1("Line Chart Demo");
demo.pack();
RefineryUtilities.centerFrameOnScreen(demo);
demo.setVisible(true);
}
}

https://www.tutorialspoint.com/jfreechart/jfreechart_quick_guide.htm

Complete App

import org.jfree.chart.ChartPanel;
import org.jfree.chart.ChartFactory;
import org.jfree.chart.JFreeChart;
import org.jfree.ui.ApplicationFrame;
import org.jfree.ui.RefineryUtilities;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.data.category.DefaultCategoryDataset;
 
public class LineChart_AWT extends ApplicationFrame {
 
   public LineChart_AWT( String applicationTitle , String chartTitle ) {
      super(applicationTitle);
      JFreeChart lineChart = ChartFactory.createLineChart(
         chartTitle,
         "Years","Number of Schools",
         createDataset(),
         PlotOrientation.VERTICAL,
         true,true,false);
 
      ChartPanel chartPanel = new ChartPanel( lineChart );
      chartPanel.setPreferredSize( new java.awt.Dimension( 560 , 367 ) );
      setContentPane( chartPanel );
   }
 
   private DefaultCategoryDataset createDataset( ) {
      DefaultCategoryDataset dataset = new DefaultCategoryDataset( );
      dataset.addValue( 15 , "schools" , "1970" );
      dataset.addValue( 30 , "schools" , "1980" );
      dataset.addValue( 60 , "schools" ,  "1990" );
      dataset.addValue( 120 , "schools" , "2000" );
      dataset.addValue( 240 , "schools" , "2010" );
      dataset.addValue( 300 , "schools" , "2014" );
      return dataset;
   }
 
   public static void main( String[ ] args ) {
      LineChart_AWT chart = new LineChart_AWT(
         "School Vs Years" ,
         "Numer of Schools vs years");
 
      chart.pack( );
      RefineryUtilities.centerFrameOnScreen( chart );
      chart.setVisible( true );
   }
}

JPEG Image Creation
Let us re-write the above example to generate a JPEG image from a command line.

import java.io.*;
 
import org.jfree.chart.JFreeChart; 
import org.jfree.chart.ChartFactory; 
import org.jfree.chart.ChartUtilities; 
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.data.category.DefaultCategoryDataset;
 
public class LineChart {
 
   public static void main( String[ ] args ) throws Exception {
      DefaultCategoryDataset line_chart_dataset = new DefaultCategoryDataset();
      line_chart_dataset.addValue( 15 , "schools" , "1970" );
      line_chart_dataset.addValue( 30 , "schools" , "1980" );
      line_chart_dataset.addValue( 60 , "schools" , "1990" );
      line_chart_dataset.addValue( 120 , "schools" , "2000" );
      line_chart_dataset.addValue( 240 , "schools" , "2010" ); 
      line_chart_dataset.addValue( 300 , "schools" , "2014" );
 
      JFreeChart lineChartObject = ChartFactory.createLineChart(
         "Schools Vs Years","Year",
         "Schools Count",
         line_chart_dataset,PlotOrientation.VERTICAL,
         true,true,false);
 
      int width = 640;    /* Width of the image */
      int height = 480;   /* Height of the image */ 
      File lineChart = new File( "LineChart.jpeg" ); 
      ChartUtilities.saveChartAsJPEG(lineChart ,lineChartObject, width ,height);
   }
}