小编Igg*_*lob的帖子

我正在将事件记录到mySQL数据库中,并希望获得前3个事件用于监视目的.

我的表eventlog看起来像这样:

+----+------------------+---------------------+
| id |    eventname     |      eventdate      |
+----+------------------+---------------------+
|  0 | machine1.started | 2016-09-04 19:22:23 |
|  1 | machine2.reboot  | 2016-09-04 20:23:11 |
|  2 | machine1.stopped | 2016-09-04 20:24:12 |
|  3 | machine1.started | 2016-09-04 20:25:12 |
|  4 | machine1.stopped | 2016-09-04 23:23:16 |
|  5 | machine0.started | 2016-09-04 23:24:00 |
|  6 | machine1.started | 2016-09-04 23:24:16 |
|  7 | machine3.started | 2016-09-04 23:25:00 |
|  8 | …

我有一个JavaFX UI，允许用户指定时间跨度。它包含两个DatePicker，一个用于选择时间范围的开始日期，另一个用于选择时间范围的结束日期。

显然，我不希望用户选择开始日期在结束日期之后，反之亦然。

我已经DayCellFactory为两个日期选择器设置了自定义，如/sf/answers/3246106601/中所述。该操作按预期的方式在DatePickers初始化期间指定的初始时间范围内使用。但是，例如，如果用户随后选择其他开始日期，则结束日期DatePicker仍会显示初始可选日期，并且不会将其可选日期调整为新的开始日期。这是我使用属性侦听器的方法，这当然不起作用：

public final class DatePickerUtil {

    public static void constrainLowerUpperBounds(DatePicker lowerBoundDatePicker, DatePicker upperBoundDatePicker) {
        LocalDate lowerBound = lowerBoundDatePicker.getValue();
        LocalDate upperBound = upperBoundDatePicker.getValue();

        if (lowerBound.isAfter(upperBound)) {
            throw new IllegalStateException("Upper bound date picker has older date than lower bound date picker");
        }

        lowerBoundDatePicker.setEditable(true);
        upperBoundDatePicker.setEditable(true);

        lowerBoundDatePicker.setDayCellFactory(createDayCellFactory(null, upperBound));
        upperBoundDatePicker.setDayCellFactory(createDayCellFactory(lowerBound, null));

        lowerBoundDatePicker.valueProperty().addListener((observable, oldValue, newValue) -> {
            upperBoundDatePicker.setDayCellFactory(createDayCellFactory(newValue, null));
        });

        upperBoundDatePicker.valueProperty().addListener(((observable, oldValue, newValue) -> {
            lowerBoundDatePicker.setDayCellFactory(createDayCellFactory(null, newValue));
        }));
    }

    private static Callback<DatePicker, DateCell> createDayCellFactory(LocalDate lowerBound, LocalDate upperBound) {
        return …

我的数据模型定义了多个结构,它们都有两个共同的字段:a StartDate和an EndDate.我需要将这两个字段格式化为2018-09-21编组的JSON,因此结构实现了Marshaller接口:

type Results struct {
    Source     string    `json:"source"`
    StartDate  time.Time 
    EndDate    time.Time 
}

type WeightedResults struct {
    Source          string           `json:"source"`
    StartDate       time.Time        
    EndDate         time.Time        
}

func (r Results) MarshalJSON() ([]byte, error) {
    type Alias Results
    if equalDate(r.StartDate, r.EndDate) {
        return json.Marshal(&struct {
            Date string `json:"date"`
            Alias
        }{
            Date:  r.StartDate.Format(dateFormat),
            Alias: (Alias)(r),
        })
    }    
    return json.Marshal(&struct {
        StartDate string `json:"start_date"`
        EndDate   string `json:"end_date"`
        Alias
    }{
        StartDate: r.StartDate.Format("2006-01-02"),
        EndDate:   r.EndDate.Format("2006-01-02"),
        Alias:     (Alias)(r),
    })
} …