JDBCCategoryDataset - 执行多个查询 [英] JDBCCategoryDataset - execute multiple queries

问题描述

我想使用 JDBCCategoryDataset class。

I want to create three charts inside a JFrame using the JDBCCategoryDataset class.

如何提供三个单独的查询？我在数据集对象中给出了三个不同的查询，但结果显示了三个相似的图表。另外，它执行所有三个的最后一个查询。我已经看到了 DefaultPieDataset 给定默认（静态）值，但我想从数据库中动态检索数据。

How can I give three separate queries? I gave three different queries in the dataset object, but the result was to display three similar charts. In addition, it executes the last query for all three. I have seen the way it is done with DefaultPieDataset given default (static) values, but I want to retrieve data dynamically from database.

我知道我可以创建几个 JDBCCategoryDataset 对象？还有更好的方法吗？

I know I can create several JDBCCategoryDataset objects? Is there a better way?

package barchart;

import Extra.OpenFile;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.sql.SQLException;
import javax.swing.JFrame;
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.plot.CategoryPlot;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.renderer.category.BarRenderer;
import org.jfree.data.jdbc.JDBCCategoryDataset;
import org.jfree.ui.RefineryUtilities;

public class Chart {
        public static void main(String[] args) throws IOException {

           try {
           JDBCCategoryDataset dataset = new JDBCCategoryDataset(
            "jdbc:mysql://localhost:3306/jobfinder",
            "com.mysql.jdbc.Driver","giannis", "giannis");

           JFrame frame = new JFrame("Charts");
           frame.setLayout(new GridLayout(2,1));

           String query = "";
           query = OpenFile.getContent("query"); //Gets the query from a file
                                                // cause it's big.It's a custom class.
           dataset.executeQuery(query);
           JFreeChart chart =
           ChartFactory.createBarChart3D("Job Statistics", "Posts/Replys", "Quantity",
           dataset, PlotOrientation.VERTICAL, true, true, false);

           chart.setBackgroundPaint(Color.white);
           CategoryPlot plot = (CategoryPlot) chart.getPlot();
           plot.setBackgroundPaint(Color.lightGray);
           plot.setRangeGridlinePaint(Color.white);

           BarRenderer renderer = (BarRenderer) plot.getRenderer();
           renderer.setSeriesPaint(1, Color.CYAN);
           renderer.setSeriesPaint(0, Color.DARK_GRAY);
           renderer.setDrawBarOutline(false);
           renderer.setItemMargin(0.0);

           ChartPanel chartPanel = new ChartPanel(chart, false);
           chartPanel.setPreferredSize(new Dimension(700, 270));

           frame.add(chartPanel);


//               query = "SELECT occuDscr Jobs,COUNT(pstOccuId) Quantity FROM occupation_field " +
//                       "INNER JOIN job_post ON occuId = pstOccuId GROUP BY Jobs";
//               dataset.executeQuery(query);
//               JFreeChart chart1 =
//               ChartFactory.createBarChart3D("Job Statistics", "Posts/Replys", "Quantity",
//               dataset, PlotOrientation.VERTICAL, true, true, false);
//
//               ChartPanel chartPanel1 = new ChartPanel(chart1, false);
//               chartPanel.setPreferredSize(new Dimension(500/2, 270/2));
//
//               frame.add(chartPanel1);
//
//               query = "SELECT occuDscr Jobs,COUNT(usrOccuId) Quantity FROM occupation_field " +
//                       "INNER JOIN users ON occuId = usrOccuId GROUP BY Jobs";
//               dataset.executeQuery(query);
//               JFreeChart chart2 =
//               ChartFactory.createBarChart3D("Job Statistics", "Posts/Replys", "Quantity",
//               dataset, PlotOrientation.VERTICAL, true, true, false);
//
//               ChartPanel chartPanel2 = new ChartPanel(chart2, false);
//               chartPanel.setPreferredSize(new Dimension(500/2, 270/2));
//
//              frame.add(chartPanel2);

           frame.setVisible(true);
           frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
           frame.pack();

           RefineryUtilities.centerFrameOnScreen(frame);

       } catch (FileNotFoundException fe) {
             System.out.println("Error Occurred " + fe.getMessage());
             System.exit(0);
       } catch (IOException ie) {
             System.out.println("Error Occurred " + ie.getMessage());
             System.exit(0);
       } catch (ClassNotFoundException ce) {
             System.out.println("Error Occurred " + ce.getMessage());
             System.exit(0);
      }  catch (SQLException se) {
             System.out.println("Error Occurred " + se.getMessage());
             System.exit(0);
      }
   }
}

推荐答案

从概念上讲，最简单的方法是给每个面板提供自己的查询特定的 JDBCCategoryDataset 。在这个相关的示例中，每个 ThermometerDemo 面板都有自己的 DefaultValueDataset 。

Conceptually, the simplest approach is to give each panel it's own query-specific JDBCCategoryDataset. In this related example, each ThermometerDemo panel has it's own DefaultValueDataset.

或者，定义一个具有单个 JDBCCategoryDataset 的类它检索组成三个 CategoryDataset 实例所需的所有数据，并公开静态工厂方法，每个方法返回每个饼图所需的单个数据集。

Alternatively, define a class having a single JDBCCategoryDataset that retrieves all the data required to compose three CategoryDataset instances, and expose static factory methods that each return the individual dataset required for each pie chart.

附录：后一种方法假设有一些有用的启发式方法来区分完整结果集的子集。例如，这是连续子集的部分实现：

Addendum: The latter approach assumes that there is some useful heuristic to distinguish among subsets of the full result set. As an example, here's a partial implementation for contiguous subsets:

/** @see https://stackoverflow.com/questions/8835974 */
public class MyCategoryDataset implements CategoryDataset{

    private JDBCCategoryDataset set;
    private List subList;

    private MyCategoryDataset(JDBCCategoryDataset set, int first, int last) {
        this.set = set;
        subList = set.getRowKeys().subList(first, first);
    }

    public static CategoryDataset createSubset(
            JDBCCategoryDataset set, int first, int last) {
        return new MyCategoryDataset(set, first, first);
    }

    @Override
    public Comparable getRowKey(int row) {
        return (Comparable) subList.get(row);
    }

    @Override
    public int getRowIndex(Comparable key) {
        return subList.indexOf(key);
    }

    @Override
    public List getRowKeys() {
        return subList;
    }

    // TODO
    //@Override
    //public Comparable getColumnKey(int column) {}
    //
    //@Override
    //public int getColumnIndex(Comparable key) {}
    //
    //@Override
    //public List getColumnKeys() {}
    //
    //@Override
    //public Number getValue(Comparable rowKey, Comparable columnKey) {}
    //
    //@Override
    //public int getRowCount() {}
    //
    //@Override
    //public int getColumnCount() {}
    //
    //@Override
    //public Number getValue(int row, int column) {}
    //
    //@Override
    //public void addChangeListener(DatasetChangeListener listener) {}
    //
    //@Override
    //public void removeChangeListener(DatasetChangeListener listener) {}
    //
    //@Override
    //public DatasetGroup getGroup() {}
    //
    //@Override
    //public void setGroup(DatasetGroup group) {}
}

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