jfreechart飞速应用

jfreechart火速应用

import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartUtilities;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.data.category.DefaultCategoryDataset;
import org.jfree.data.general.DefaultPieDataset;

public class ChartServlet extends HttpServlet
{


?public void doPost( HttpServletRequest request, HttpServletResponse response)
???throws ServletException, IOException
?{
??
//这里先得到一个vote的对象实例
?? Vote vote=getvote();

??
??// 得到JFreeChart对象的实例
??JFreeChart chart = getChart( vote );

??// 设置输出对象的类型
??response.setContentType( "image/jpeg" );

??// 输出图形
??ChartUtilities.writeChartAsJPEG( response.getOutputStream(),
???100, chart, 400, 300, null);
?}
?
?
?public void doGet( HttpServletRequest request, HttpServletResponse response )
???throws ServletException, IOException
?{
??doPost( request, response );
?}

// 得到JFreeChart对象的实例
?public static JFreeChart getChart( Vote vote )
?{
??JFreeChart chart = null;

??// 判断是否为饼图
??if(?.... )
??{
???// 组织生成饼图的数据
???DefaultPieDataset data = new DefaultPieDataset();
???
???Iterator it = vote.getVoteitems().iterator();

//遍历数据集
???while( it.hasNext() )
???{
????VoteItem vi = (VoteItem)it.next();
//设置要显示图形每一项的标题，具体数字（这里是投票数vi.getvotenum了)
????data.setValue( vi.getTitle(), vi.getVotenum() );
???}
???
???// 判断是否为普通饼图
???if(?..... )
???{
????chart = ChartFactory.createPieChart( vote.getTitle(),
??????data, false, false, false );
???}
???else?// 3D饼图
???{
????chart = ChartFactory.createPieChart3D( vote.getTitle(),
??????data, false, false, false );
???}
??}
??else
??{
???// 组织柱状图的数据
???DefaultCategoryDataset data = new DefaultCategoryDataset();
???
???Iterator it = vote.getVoteitems().iterator();
???while( it.hasNext() )
???{
????VoteItem vi = (VoteItem)it.next();
????data.addValue( vi.getVotenum(), "选项", vi.getTitle() );
???}

???// 判断是否为普通柱状图
???if(?.... )
???{
????chart = ChartFactory.createBarChart( vote.getTitle(),
?????"选项", "数量", data, PlotOrientation.VERTICAL,
?????false, false, false );
???}
???else?// 3D柱状图
???{
????chart = ChartFactory.createBarChart3D( vote.getTitle(),
??????"选项", "数量", data, PlotOrientation.VERTICAL,
??????false, false, false );
???}
??}
??return chart;
?}
}