如何使用掩码从JFormattedTextField获取日期

本文介绍了如何使用掩码从JFormattedTextField获取日期的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我花了很多时间阅读Java文档和相关问题，但仍然无法准确了解我需要做什么来完成我想要的。

我知道我将使用 MaskFormatter （因为我想要 / / 总是显示）， SimpleDateFormater 和 DocumentListeners 所以我花了大部分时间研究这些，但无法弄清楚如何一起使用所有的东西。

我有一个 JFormattedTextField 使用 MaskFormatter（## / ## / ####）我想最终以 MM / dd / yyyy 的格式存储为日期。

  private JFormattedTextField weekEndingData = new JFormattedTextField（createFormatter（## / ## / ####））; 
 private String dateString = weekEndingData.toString（）; 
 private SimpleDateFormat dateFormatter = new SimpleDateFormat（MM / dd / yyyy）;

  private MaskFormatter createFormatter（String s）{
 MaskFormatter formatter = null; 
 try {
 formatter = new MaskFormatter（s）; 
} catch（java.text.ParseException exc）{
 System.err.println（formatter is bad：+ exc.getMessage（））; 
 System.exit（-1）; 
} 
 return formatter; 
}

此日期反映了我的情况下星期天的周结束日期。该日期将被发送到数据库，并且还将用于自动显示一周中剩余时间的日期。所以例如：

如果用户输入的周结束日期是3/30/2014，则表单上的JLabel将填写为3/30文字星期日，星期六下午3点29分，直到星期一。这让我进入下一个问题，减去日期。

我已经完成了研究，只是到了JodaTime的任何地方，但是我也看到有人提到新的Java8 JDK在日期方面，解决了Java以前的许多弱点。

我正在寻找指导方针，列出我想要完成的要求，因为我觉得很混乱，似乎找不到足够强的方向。我也希望有关JDK8使用日期的方式的任何反馈，如果它比Joda更好的选择。（我知道主观性在这里皱着眉头，但我不知道还有什么要问的。）

编辑可视化可能有帮助。此专家组将被印刷，所以JSpinner是不利的。黄色只是暂时的，以帮助我可视化空间分配。

解决方案

有更好的选择允许用户在Swing中输入日期，但在第三方库中：

JDateChooser 可在中使用

JXDatePicker 可在中使用

但是，如果您不想使用任何第三方库，而不是使用标准的Swing组件，建议您使用。请参阅教程。

此代码段应该足以使其正常工作：

  SpinnerDateModel model = new SpinnerDateModel ）; 
 JSpinner spinner = new JSpinner（model）; 
 
 JSpinner.DateEditor editor = new JSpinner.DateEditor（spinner，MM / dd / yyyy）; 
 DateFormatter formatter =（DateFormatter）editor.getTextField（）。getFormatter（）; 
 formatter.setAllowsInvalid（false）; 
 formatter.setOverwriteMode（true）; 
 
 spinner.setEditor（editor）;

为了正常工作，我没有尝试Java 8，但有一个官方的踪迹：

如果您不想使用新的API，那么您可以使用（旧学院 API）。例如：

  Date date =（Date）spinner.getModel（）。getValue（）; 
日历calendar = Calendar.getInstance（）; 
 calendar.setTime（date）; 
 if（calendar.get（Calendar.DAY_OF_WEEK）== Calendar.SUNDAY）{
 System.out.println（今天是星期天！）; 
}

如果你想减少一天，你可以做如下：

  calendar.add（Calendar.DAY_OF_MONTH，-1）;

这个问题也有很好的答案：

I've spent a lot of time reading Java docs and related questions but am still unable to understand exactly what I need to do to accomplish what I want.

I know that I will be using a MaskFormatter (because I want / / always displayed), SimpleDateFormater and DocumentListeners so I spent most of my time studying those but can't figure out how to use everything together.

I have a JFormattedTextField that uses a MaskFormatter("##/##/####") which I want to end up being stored as a Date in the format of MM/dd/yyyy.

    private JFormattedTextField weekEndingData = new JFormattedTextField(createFormatter("##/##/####"));
    private String dateString = weekEndingData.toString();
    private SimpleDateFormat dateFormatter = new SimpleDateFormat("MM/dd/yyyy");

        private MaskFormatter createFormatter(String s) {
        MaskFormatter formatter = null;
        try {
            formatter = new MaskFormatter(s);
        } catch (java.text.ParseException exc) {
            System.err.println("formatter is bad: " + exc.getMessage());
            System.exit(-1);
        }
        return formatter;
    }

This date reflects the "week ending date" which is Sunday in my case. This date will be sent to a database and will also be used to automatically display the dates of the rest of the days in the week. So for example:

If the week ending date entered by the user is 3/30/2014, then a JLabel on the form will fill in as 3/30 under the text "Sunday", and 3/29 under Saturday, and so on till monday. Which brings me to my next issue, subtracting dates.

I've done research and just about everywhere points towards JodaTime, but I also saw someone mention that the new Java8 JDK addresses much of the previous weak points for Java in terms of Dates.

I am looking for guidance in terms of mapping/listing out my requirements for what I want to accomplish because I feel very muddled and can't seem to find strong enough direction. I am also hoping for any feedback on the way JDK8 uses dates and if it is a better choice than Joda. (I know subjectiveness is frowned upon here but I don't know where else to ask.)

EDIT a visualization may help. This Panel will be printed so a JSpinner is unfavorable. The yellow is only there temporarily to help me visualize space distribution.

解决方案

There are better choices to allow users input dates in Swing, but in third-party libraries:

JDateChooser available in JCalendar library
JXDatePicker available in SwingX libary

However if you don't want to use any third-party library but standard Swing components instead, I'd suggest you use JSpinner with a date model. See How to Use Spinners tutorial.

This code snippet should be enough to get it work:

SpinnerDateModel model = new SpinnerDateModel();
JSpinner spinner = new JSpinner(model);

JSpinner.DateEditor editor = new JSpinner.DateEditor(spinner, "MM/dd/yyyy");
DateFormatter formatter = (DateFormatter)editor.getTextField().getFormatter();
formatter.setAllowsInvalid(false);
formatter.setOverwriteMode(true);

spinner.setEditor(editor);

In order to work with dates honestly I didn't try Java 8 yet, but there's an official trail: Trail: Date Time

If you don't want to use the new API then you can use Calendar API (the old school API). For instance:

Date date = (Date)spinner.getModel().getValue();
Calendar calendar = Calendar.getInstance();
calendar.setTime(date);
if(calendar.get(Calendar.DAY_OF_WEEK) == Calendar.SUNDAY) {
    System.out.println("Today is Sunday!");
}

If you want to substract a day you can do as follows:

calendar.add(Calendar.DAY_OF_MONTH, -1);

There are good answers in this question too: How can I increment a date by one day in Java?

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