我正在尝试在我的应用程序中制作一个图表,该图表可以返回几个月内各天的温度。
该图表是 JFreechart TimeSeriesCollection,我无法让该图表从数据库读取正确的数据。
它显示了一些值,但不是全部,并且不显示正确的时间。
为了解决这个问题,我尝试实现发布的图表here,但仍然无法解决我的问题,即使去看了这个question,正如人们建议的那样
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);
}
}
![enter image description here](https://i.stack.imgur.com/S3aCb.png)
这是我的代码的结果图表。
但查询的结果是:
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...
如此处所示,它不显示所有值,也不列出小时。
- - - - - - - - - - - 编辑 - - - - - - - - - - -
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'
实现这个并没有改变输出。