從Mysql DB填充JFreechart TimeSeriesCollection？

Question

我正在試圖在我的應用程序中創建一個圖表，讓我在幾個月內返回天數的溫度。

此圖表是JFreechart TimeSeriesCollection，我無法從圖表中讀取數據庫中的正確數據。

它顯示了一些值，但不是全部，並且沒有顯示正確的時間。

爲了解決這個問題，我試圖執行圖形張貼here，但還是沒能解決我的問題，甚至不必去看看這個question，因爲人們認爲

public class NewClass extends ApplicationFrame { 

Connection conexao = null; 
PreparedStatement pst= null; 
ResultSet rs = null; 

public NewClass(String title) throws SQLException, ParseException { 
    super(title); 
    ChartPanel chartPanel = (ChartPanel) createDemoPanel(); 
    chartPanel.setPreferredSize(new java.awt.Dimension(500, 270)); 
    setContentPane(chartPanel); 


} 


private static JFreeChart createChart(XYDataset dataset) { 

    JFreeChart chart = ChartFactory.createTimeSeriesChart(
     "Temperatura/Date", // title 
     "Date",    // x-axis label 
     "Temperatura", // y-axis label 
     dataset,   // data 
     true,    // create legend? 
     true,    // generate tooltips? 
     false    // generate URLs? 
    ); 


    XYPlot plot = (XYPlot) chart.getPlot(); 

    DateAxis axis = (DateAxis) plot.getDomainAxis(); 
    axis.setDateFormatOverride(new SimpleDateFormat("yyyy-MM-dd")); 

    return chart; 

} 


private static XYDataset createDataset() throws SQLException, ParseException { 
    Connection con = null; 
    String databaseURL = "jdbc:mysql://localhost:3306/world"; 
    String driverName = "com.mysql.jdbc.Driver"; 
    String user = "root"; 
    String password = "rootadmin"; 
    try { 
     Class.forName(driverName).newInstance(); 
    } catch (Exception ex) { 
     System.out.println(""); 
    } 

     con = (Connection) DriverManager.getConnection(databaseURL, user, password); 

     if (!con.isClosed()) { 
      System.out.println("Successfully connected to the DataBase Server..."); 
     } 


     Statement statement; 
     statement = (Statement) con.createStatement(); 

     String selectQuery = "select (CONCAT(`data_registo`, ' ', hora_registo)) as data, temperatura, idSensor from registos where idSensor like 'BrgTH001' "; 
     ResultSet resultSet = null; 
     resultSet = statement.executeQuery(selectQuery); 




    TimeSeries s1 = new TimeSeries("Thermomether01"); 
    while (resultSet.next()) { 

       String idSensor = (String) resultSet.getObject("idSensor"); 
       String data = (String) resultSet.getObject("data"); 
       String temperatura = (String) resultSet.getObject("temperatura"); 

       SimpleDateFormat sdf2 = new SimpleDateFormat("yyyy-MM-dd HH:mm"); 
       Date dateI = sdf2.parse(data); 


       System.out.println("" + idSensor + " " + data + " " + temperatura+ " | "); 


       s1.addOrUpdate(new Hour(dateI), value); 



      } 

     resultSet.close(); 



    TimeSeriesCollection dataset = new TimeSeriesCollection(); 
    dataset.addSeries(s1); 


    return dataset; 


} 

public static JPanel createDemoPanel() throws SQLException, ParseException { 
    JFreeChart chart = createChart(createDataset()); 
    ChartPanel panel = new ChartPanel(chart); 
    panel.setFillZoomRectangle(true); 
    panel.setMouseWheelEnabled(true); 
    return panel; 
} 


public static void main(String[] args) throws SQLException, ParseException { 

    NewClass demo = new NewClass("Chart"); 
    demo.pack(); 
    demo.setVisible(true); 

} 

} 

這是我的代碼的結果圖表。 但查詢的結果是：

Thermomether01 2014-04-01 08:47:11 23.8 | 
Thermomether01 2014-04-01 08:47:11 23.8 | 
Thermomether01 2014-04-01 08:51:20 23.9 | 
Thermomether01 2014-04-01 08:53:24 23.9 | 
Thermomether01 2014-04-01 08:55:28 23.9 | 
Thermomether01 2014-04-01 09:43:26 24.1 | 
Thermomether01 2014-04-01 09:48:39 24.0 | 
Thermomether01 2014-04-01 09:50:44 24.1 | 
Thermomether01 2014-04-01 09:52:48 24.0 | 
Thermomether01 2014-04-01 09:54:52 24.1 | 
Thermomether01 2014-04-01 09:56:56 24.1 | 
Thermomether01 2014-04-01 09:59:01 24.1 | 
    . 
    . 
    . 
Thermomether01 2014-06-13 09:35:36 19.2 | 
Thermomether01 2014-06-13 10:03:00 18.7 | 
Thermomether01 2014-06-13 10:33:41 19.0 | 
Thermomether01 2014-06-16 08:57:57 19.1 | 
Thermomether01 2014-06-16 09:07:54 18.9 | 
Thermomether01 2014-06-16 09:08:40 19.0 | 
Thermomether01 2014-06-16 09:36:28 19.1 | 
Thermomether01 2014-06-16 10:03:51 18.8 | 
Thermomether01 2014-06-16 10:31:14 19.2 | 
Thermomether01 2014-06-16 11:00:17 19.1 | 
Thermomether01 2014-06-16 11:27:38 19.2 | 
Thermomether01 2014-06-16 11:54:59 19.1 | 
Thermomether01 2014-06-16 12:51:24 18.5 | 

ETC ...

如圖所示，它並沒有顯示所有的值以及沒有列出小時。

----------------------編輯----------------------

select (CONCAT(`data_registo`, ' ', hora_registo)) as data, temperatura, idSensor from registos where idSensor like 'Thermometer01' and temperatura not in ('---') and data_registo between '2014-06-01' and '2014-06-10' 

執行此操作不會改變輸出。

Answer 1

我懷疑你在將String轉換爲Date時失去了精確度。這個完整的示例在內存中創建一個合適的數據庫表，將其查詢到JDBCXYDataset中，並在時間序列圖中顯示數據集。請注意，JDBCXYDataset可識別時間序列數據。作爲支票，JDBCXYDataset被查詢返回的日期值。

典型的每小時數據：

 
… 
Jul 15, 2014 1:10:25 PM 
Jul 15, 2014 2:10:25 PM 
Jul 15, 2014 3:10:25 PM 
Jul 15, 2014 4:10:25 PM 
Jul 15, 2014 5:10:25 PM 
Jul 15, 2014 6:10:25 PM 
… 

代碼：

import java.awt.EventQueue; 
import java.sql.Connection; 
import java.sql.Date; 
import java.sql.DriverManager; 
import java.sql.PreparedStatement; 
import java.sql.SQLException; 
import java.sql.Statement; 
import java.sql.Timestamp; 
import java.text.DateFormat; 
import java.util.Calendar; 
import java.util.Random; 
import javax.swing.JFrame; 
import org.jfree.chart.ChartFactory; 
import org.jfree.chart.ChartPanel; 
import org.jfree.chart.JFreeChart; 
import org.jfree.data.jdbc.JDBCXYDataset; 

/** 
* @see http://stackoverflow.com/a/24762078/230513 
*/ 
public class JDBCTest { 

    private static final int N = 24; 
    private static final Random r = new Random(); 

    private void display() { 
     JFrame f = new JFrame("JDBCTest"); 
     f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
     JDBCXYDataset jds = createDataset(); 
     JFreeChart chart = ChartFactory.createTimeSeriesChart(
      "Inventory", "Date", "Count", jds, true, true, false); 
     f.add(new ChartPanel(chart)); 
     f.pack(); 
     f.setLocationRelativeTo(null); 
     f.setVisible(true); 
     for (int i = 0; i < jds.getItemCount(); i++) { 
      System.out.println(DateFormat.getDateTimeInstance() 
       .format(new Date(jds.getX(0, i).longValue()))); 
     } 
    } 

    private JDBCXYDataset createDataset() { 
     try { 
      Connection conn = DriverManager.getConnection(
       "jdbc:h2:mem:test", "", ""); 
      Statement st = conn.createStatement(); 
      st.execute("create table inventory(when timestamp, n1 integer, n2 integer)"); 
      PreparedStatement ps = conn.prepareStatement(
       "insert into inventory values (?, ?, ?)"); 
      Calendar c = Calendar.getInstance(); 
      for (int i = 0; i < N; i++) { 
       ps.setTimestamp(1, new Timestamp(c.getTimeInMillis())); 
       ps.setInt(2, N/3 + r.nextInt(N/2)); 
       ps.setInt(3, N/2 + r.nextInt(N/2)); 
       ps.execute(); 
       c.add(Calendar.HOUR_OF_DAY, 1); 
      } 
      JDBCXYDataset jds = new JDBCXYDataset(conn); 
      jds.executeQuery("select when, n1, n2 from inventory"); 
      return jds; 
     } catch (SQLException ex) { 
      ex.printStackTrace(System.err); 
     } 
     return null; 
    } 

    public static void main(String[] args) { 
     EventQueue.invokeLater(new Runnable() { 
      @Override 
      public void run() { 
       new JDBCTest().display(); 
      } 
     }); 
    } 
}