将jcalendar日期转换为XMLGregorianCalendar获取空值

问题描述

我有一些问题，我只是从jCalendar中的jDateChooser获取空值。

此方法是将java.util.Date转换为XMlGregorianCalendar的功能：

  DatatypeFactory df; 
 public XMLGregorianCalendar function_ConvertAsXMLGregorianCalendar（Date date）{
 if（date == null）{
 System.out.println（函数将日期转换成XML格里高利日历时出错）; 
返回null; 
} else {
 GregorianCalendar gc = new GregorianCalendar（）; 
 gc.setTimeInMillis（date.getTime（））; 
 return df.newXMLGregorianCalendar（gc）; 
} 
} 
  

这是getStart和getEnd日期的2个函数。

  private XMLGregorianCalendar getStartDate（）{
 Date dateStarting = jDateChooserStart.getDate（）; 
 System.out.println（Date Start：+ dateStarting.toString（））; 
 XMLGregorianCalendar cal = function_ConvertAsXMLGregorianCalendar（dateStarting）; 
 System.out.println（转换日期：+ cal.toXMLFormat（））; 
返回cal; 
} 
 
 private XMLGregorianCalendar getEndDate（）{
 Date dateEnding = jDateChooserEnd.getDate（）; 
 System.out.println（Date End：+ dateEnding）; 
 return function_ConvertAsXMLGregorianCalendar（dateEnding）; 
} 
  

然后我只需将方法放在一个名为schedule的对象中：

  schedule.setStartDate（getStartDate（））; 
 schedule.setEndDate（getEndDate（））; 
  

Netbeans（v7.1）的结果

 线程中的异常AWT-EventQueue-0java.lang.NullPointerException 
在Frames.CreateSchedule.function_ConvertAsXMLGregorianCalendar（CreateSchedule.java:181）
在帧。 CreateSchedule.getStartDate（CreateSchedule.java:188）
在Frames.CreateSchedule.SubmitButtonActionPerformed（CreateSchedule.java:204）
在Frames.CreateSchedule.access $ 000（CreateSchedule.java:16）
  

发生了什么？

b
$ b

更新::

我只是将功能更改为：

  public XMLGregorianCalendar function_ConvertAsXMLGregorianCalendar（Date date）{
 if（date == null）{
 System.out.println（函数将日期转换为XML公历）; 
返回null; 
} else {
 GregorianCalendar gc = new GregorianCalendar（）; 
 gc.setTimeInMillis（date.getTime（））; 
 DatatypeFactory df = null; 
 return df.newXMLGregorianCalendar（gc）; 
} 
} 
  

更新2＃::

初始化newInstance（）方法后，我会收到另一个错误：

 code> java.lang.ClassCastException：java.util.Date不能转换为java.sql.Date 
  

我只是将包名从

  java.util.Date更改为java.SQL.Date 
  

然后转换：

  Date dateStarting =（Date）jDateChooserStart.getDate（）; 
日期dateEnding =（Date）jDateChooserEnd.getDate（）; 
  

如何解决此问题？

再次感谢

解决方案

似乎 df 已被声明但未被实例化：

  DatatypeFactory df; 
  

从这里：

  df.newXMLGregorianCalendar（gc）; 
 ^ 
  

您可以使用首先实例化，像这样： p>

  DatatypeFactory df = DatatypeFactory.newInstance（）; 
  

i have some problem, i just getting null value from jDateChooser in jCalendar.

This method is function to convert java.util.Date into XMlGregorianCalendar :

DatatypeFactory df;
public XMLGregorianCalendar function_ConvertAsXMLGregorianCalendar(Date date) {
    if (date == null) {
        System.out.println("Error on Function Convert Date into XML Gregorian Calendar");
        return null; 
    } else {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTimeInMillis(date.getTime());
        return df.newXMLGregorianCalendar(gc);
    }
}

And this is 2 function which getStart and getEnd Dates.

private XMLGregorianCalendar getStartDate(){
    Date dateStarting  = jDateChooserStart.getDate();
    System.out.println("Date Start : " + dateStarting.toString());
    XMLGregorianCalendar cal = function_ConvertAsXMLGregorianCalendar(dateStarting);
    System.out.println("Converted Date : " + cal.toXMLFormat());
    return cal;
}

private XMLGregorianCalendar getEndDate(){
    Date dateEnding = jDateChooserEnd.getDate();
    System.out.println("Date End : " + dateEnding);
    return function_ConvertAsXMLGregorianCalendar(dateEnding);
}

Then i just place the method inside an object called schedule:

schedule.setStartDate(getStartDate());
schedule.setEndDate(getEndDate());

Result from Netbeans(v7.1)

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at Frames.CreateSchedule.function_ConvertAsXMLGregorianCalendar(CreateSchedule.java:181)
at Frames.CreateSchedule.getStartDate(CreateSchedule.java:188)
at Frames.CreateSchedule.SubmitButtonActionPerformed(CreateSchedule.java:204)
at Frames.CreateSchedule.access$000(CreateSchedule.java:16)

what's wrong?

Thanks before.

UPDATE ::

I just change the function into this:

public XMLGregorianCalendar function_ConvertAsXMLGregorianCalendar(Date date) {
    if (date == null) {
        System.out.println("Error on Function Convert Date into XML Gregorian Calendar");
        return null; 
    } else {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTimeInMillis(date.getTime());
        DatatypeFactory df = null;
        return df.newXMLGregorianCalendar(gc);
    }
}

UPDATE 2# ::

After initializing the newInstance() method, i'm getting another error:

java.lang.ClassCastException: java.util.Date cannot be cast to java.sql.Date

I just change the package name from

java.util.Date into java.SQL.Date

then casting:

Date dateStarting  = (Date) jDateChooserStart.getDate();
Date dateEnding    = (Date) jDateChooserEnd.getDate();

How to resolve this issue?

thanks again.

解决方案

It appears that df is declared but not instantiated:

DatatypeFactory df;

from here:

df.newXMLGregorianCalendar(gc);
^

You can use DatatypeFactory.newInstance() to instantiate first, like so:

DatatypeFactory df = DatatypeFactory.newInstance(); 

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