java - 如何用java中的数据库中的日期绘制甘特图

Question

我在从数据库获取任务的开始日期和结束日期来绘制图表时遇到问题

public IntervalCategoryDataset getCategoryDataset() {
    conn = ConnectDB.ConnectDB();
    TaskSeriesCollection dataset = new TaskSeriesCollection();

    String sql = "SELECT `TITRE`, `DATE DEBUT Prévi`, `DATE FIN prévi` FROM `projet`;";
    try {
        pst = conn.prepareStatement(sql);
        rs = pst.executeQuery(sql);
        while (rs.next()) {
            String a = rs.getString("TITRE");
            Date StartDate = rs.getDate("DATE DEBUT Prévi");
            Date EndDate = rs.getDate("DATE FIN prévi");
            Names.add(a);
            Dates.add(StartDate);
            Dates.add(EndDate);
            ++count;
        }
    } catch (Exception e) {
        JOptionPane.showMessageDialog(null, e.getMessage());
    }
    int j = 0;
    int k = 1;

    TaskSeries series1 = new TaskSeries("Estimated Date");
    for (int i = 0; i < count; i++) {
        series1.add(new Task(Names.get(i),
                Date.from(LocalDate.of(Dates.get(j).getYear(), Dates.get(j).getMonth(), Dates.get(j).getDay())
                        .atStartOfDay()
                        .toInstant(ZoneOffset.UTC)),
                Date.from(LocalDate.of(Dates.get(k).getYear(), Dates.get(k).getMonth(), Dates.get(k).getDay())
                        .atStartOfDay()
                        .toInstant(ZoneOffset.UTC))));
    }

    dataset.add(series1);
    return dataset;
}

我希望每个任务都有其图表，但所有任务都有相同的图表。

Answer 1

您应该应用单个循环，此外还可以使用 getObject(index, LocalDate.class) 或 - 如果您的驱动程序不支持前一个选项 - java.sql。 Date.toLocalDate():

public IntervalCategoryDataset getCategoryDataset() {
    conn = ConnectDB.ConnectDB();
    TaskSeriesCollection dataset = new TaskSeriesCollection();

    TaskSeries series1 = new TaskSeries("Estimated Date");
    String sql = "SELECT `TITRE`, `DATE DEBUT Prévi`, `DATE FIN prévi` FROM `projet`;";
    try {
        pst = conn.prepareStatement(sql);
        rs = pst.executeQuery(sql);
        while (rs.next()) {
            String name = rs.getString("TITRE");
            LocalDate startDate = rs.getObject("DATE DEBUT Prévi", LocalDate.class);
            LocalDate endDate = rs.getObject("DATE FIN prévi", LocalDate.class);

            series1.add(new Task(name,
                Date.from(startDate.atStartOfDay().toInstant(ZoneOffset.UTC)),
                Date.from(endDate.atStartOfDay().toInstant(ZoneOffset.UTC)));
        }
    } catch (Exception e) {
        JOptionPane.showMessageDialog(null, e.getMessage());
    }

    dataset.add(series1);
    return dataset;
}