[ Java 文章收集 ] JFreeChart 入門教學 (Part 2)

Bar Chart Demo (長條圖) :
底下我們將建立長條圖, 用來代表 John, Tom, Jill, John, Fred 的業績比較.

- 建立長條圖範例代碼

view plaincopy to clipboardprint?

1. // Create a simple Bar chart  
2. DefaultCategoryDataset dataset = new DefaultCategoryDataset();  
3. dataset.setValue(6, "Profit", "Jane");  
4. dataset.setValue(7, "Profit", "Tom");  
5. dataset.setValue(8, "Profit", "Jill");  
6. dataset.setValue(5, "Profit", "John");  
7. dataset.setValue(12, "Profit", "Fred");  
8. JFreeChart chart = ChartFactory.createBarChart("Comparison between Salesman",  
9. "Salesman", "Profit", dataset, PlotOrientation.VERTICAL,  
10. false, true, false);  

執行結果 :


- 使用說明
這裡使用的數據容器是 DefaultCategoryDataset :

view plaincopy to clipboardprint?

1. DefaultCategoryDataset dataset = new DefaultCategoryDataset();  
2. dataset.setValue(6, “Profit”, “Jane”);  

而使用建立圖表的方法是 createBarChart() :

view plaincopy to clipboardprint?

1. JFreeChart chart = ChartFactory.createBarChart(  
2.                 "Comparison between Salesman", // title  
3.                 "Salesman", // category Axis Label  
4.                 "Profit", // value Axis Label  
5.                 dataset,   
6.                 PlotOrientation.VERTICAL,  
7.                 false,   
8.                 true,   
9.                 false);  

如果要表現 3D 的 Bar Chart 也是可以拉, 透過方法 createBarChart3D(). 代碼如下 (提供數據 two bars per person):

view plaincopy to clipboardprint?

1. ...  
2.     dataset.setValue(5+rdm.nextInt(5), "Profit1", "Jane");  
3.     dataset.setValue(6+rdm.nextInt(4), "Profit2", "Jane");  
4.     dataset.setValue(3+rdm.nextInt(6), "Profit1", "Tom");  
5.     dataset.setValue(4+rdm.nextInt(6), "Profit2", "Tom");  
6.     dataset.setValue(6+rdm.nextInt(3), "Profit1", "Jill");  
7.     dataset.setValue(6+rdm.nextInt(4), "Profit2", "Jill");  
8.     dataset.setValue(7+rdm.nextInt(3), "Profit1", "John");  
9.     dataset.setValue(8+rdm.nextInt(2), "Profit2", "John");  
10.     dataset.setValue(1+rdm.nextInt(9), "Profit1", "Fred");  
11.     dataset.setValue(5+rdm.nextInt(5), "Profit2", "Fred");  
12.     JFreeChart chart = ChartFactory.createBarChart(  
13.                 "Comparison between Salesman", // title  
14.                 "Salesman", // category Axis Label  
15.                 "Profit", // value Axis Label  
16.                 dataset,   
17.                 PlotOrientation.VERTICAL,  
18.                 false,   
19.                 true,   
20.                 false);  
21. ...  

執行結果 :


最後如果你要改變圖表的外觀, 也是 Piece of cake 拉, 參考代碼如下 :

view plaincopy to clipboardprint?

1. ...  
2.     chart.setBackgroundPaint(Color.yellow); // Set the background colour of the chart  
3.     chart.getTitle().setPaint(Color.blue); // Adjust the colour of the title  
4.     CategoryPlot p = chart.getCategoryPlot(); // Get the Plot object for a bar graph  
5.     p.setBackgroundPaint(Color.black); // Modify the plot background  
6.     p.setRangeGridlinePaint(Color.red); // Modify the colour of the plot gridlines  
7. ...  

執行結果 :


Time Series Demo :
在這個範例中可以發現跟 XYChart 有點像, 只是 X 座標的輸入不再是數字而是代表時間的 Day 類別, 參考代碼如下.

- Time-Series 圖表範例代碼

view plaincopy to clipboardprint?

1. // Create a time series chart  
2. TimeSeries pop = new TimeSeries("Population", Day.class);  
3. pop.add(new Day(10, 1, 2004), 100);  
4. pop.add(new Day(10, 2, 2004), 150);  
5. pop.add(new Day(10, 3, 2004), 250);  
6. pop.add(new Day(10, 4, 2004), 275);  
7. pop.add(new Day(10, 5, 2004), 325);  
8. pop.add(new Day(10, 6, 2004), 425);  
9. TimeSeriesCollection dataset = new TimeSeriesCollection();  
10. dataset.addSeries(pop);  
11. JFreeChart chart = ChartFactory.createTimeSeriesChart(  
12.     "Population of CSC408 Town",   
13.     "Date",  
14.     "Population",  
15.     dataset,  
16.     true,  
17.     true,  
18.     false);  
19. // Change the Date format displayed in X axis  
20. XYPlot plot = chart.getXYPlot();  
21. DateAxis axis = (DateAxis) plot.getDomainAxis();  
22. axis.setDateFormatOverride(new SimpleDateFormat("dd-MM-yyyy"));  

執行結果 :


- 使用說明
這裡跟 XYChart 一樣, 需要兩個類別來記錄數據. 一個是 TimeSeries 用來記錄數據 (包含時間與對應該時間的數據) 與 TimeSeriesCollection 用來記錄多個 TimeSeries :

view plaincopy to clipboardprint?

1. TimeSeries pop = new TimeSeries("Population");  
2. TimeSeriesCollection dataset = new TimeSeriesCollection();  
3. dataset.addSeries(pop);  

接著使用方法 createTimeSeriesChart() 來建立圖表 :

view plaincopy to clipboardprint?

1. JFreeChart chart = ChartFactory.createTimeSeriesChart(  
2.                 "Population of CSC408 Town", // title  
3.                 "Date", // time Axis Label  
4.                 "Population", // value Axis Label  
5.                 dataset,  
6.                 true, // a flag specifying whether or not a legend is required.  
7.                 true, // configure chart to generate tool tips?  
8.                 false); // configure chart to generate URLs?  

最後下面的代碼是用來改變顯示的時間格式 (X axis) :

view plaincopy to clipboardprint?

1. XYPlot plot = chart.getXYPlot();  
2. DateAxis axis = (DateAxis) plot.getDomainAxis();  
3. axis.setDateFormatOverride(new SimpleDateFormat("dd-MM-yyyy"));   

This message was edited 5 times. Last update was at 01/06/2011 17:25:00