Re: [json-lib-user] Converting GregorianCalendar object, Java to JSON and back

[Darlene W. <dar...@gm...>]

Thanks Andres.  I will give this a shot.  Can you point me to some sample
code that creates a custom strategy?
thanks,
Darlene

On Fri, Jun 6, 2008 at 4:15 PM, Andres Almiray <aal...@ya...> wrote:

> Hi Darlene,
>
> There is indeed a restriction on the classes that can be used when
> serializing back to Java, they must adhere to the JavaBeans conventions
> (no-arg constructor, getters/setters, etc). It looks like GregorianCalendar
> follows suit still it throws an exception. Well no worries as you may
> register a NewBeanInstanceStrategy with JsonConfig. The default strategy
> follows the JavaBeans convention (no-arg constructor), with a custom
> strategy you are free to instantiate the class as you see fit, for example
> using a factory.
>
>
> http://json-lib.sourceforge.net/xref/net/sf/json/util/NewBeanInstanceStrategy.html
>
> Cheers,
> Andres
>
> -------------------------------------------
> http://jroller.com/aalmiray
> http://www.linkedin.com/in/aalmiray
> --
> What goes up, must come down. Ask any system administrator.
> There are 10 types of people in the world: Those who understand binary, and
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>
>
> ----- Original Message ----
> From: Darlene Wong <dar...@gm...>
> To: jso...@li...
> Sent: Friday, June 6, 2008 3:08:30 PM
> Subject: [json-lib-user] Converting GregorianCalendar object, Java to JSON
> and back
>
> Hi, I'm new to json-lib.  I want to convert a Java class into JSONObject
> and then back again.  I am able to do this conversion with a Date class.
> However, the class I want to convert contains a nested XMLGregorianCalendar
> object, which has issues when converting from JSONObject to Java.
>
> I've tried to create a simple test case that converts only a
> GregorianCalendar object (
> http://java.sun.com/javase/6/docs/api/java/util/GregorianCalendar.html).
> This works fine when converting from Java to JSONObject, but the reverse
> conversion gives an InstantiationException error when calling toJava().
> Here is my sample code:
>
>
>             GregorianCalendar gc = DateUtil.getCalendar(-7);
>             System.out.println(gc.toString());
>
>             // Convert object to JSON
>             JSONObject jsonObject = (JSONObject) JSONSerializer.toJSON(gc);
>             System.out.println(jsonObject.toString());
>
>
>             // Convert JSON object back into Java object
>             GregorianCalendar gc2;
>             JsonConfig jsonConfig = new JsonConfig();
>             jsonConfig.setRootClass(GregorianCalendar.class);
>             gc2 = (GregorianCalendar) JSONSerializer.toJava(jsonObject,
> jsonConfig);
>             System.out.println(gc2.toString());
>
>
> The output is as follows:
>
> java.util.GregorianCalendar[time=1212788878236,areFieldsSet=true,areAllFieldsSet=true,lenient=true,zone=java.util.SimpleTimeZone[id=GMT-07:00,offset=-25200000,dstSavings=3600000,useDaylight=true,startYear=0,startMode=3,startMonth=3,startDay=1,startDayOfWeek=1,startTime=7200000,startTimeMode=0,endMode=2,endMonth=9,endDay=-1,endDayOfWeek=1,endTime=7200000,endTimeMode=0],firstDayOfWeek=1,minimalDaysInFirstWeek=1,ERA=1,YEAR=2008,MONTH=5,WEEK_OF_YEAR=23,WEEK_OF_MONTH=1,DAY_OF_MONTH=6,DAY_OF_YEAR=158,DAY_OF_WEEK=6,DAY_OF_WEEK_IN_MONTH=1,AM_PM=1,HOUR=3,HOUR_OF_DAY=15,MINUTE=47,SECOND=58,MILLISECOND=236,ZONE_OFFSET=-25200000,DST_OFFSET=3600000]
>
> {"firstDayOfWeek":1,"gregorianChange":{"date":4,"day":4,"hours":16,"minutes":0,"month":9,"seconds":0,"time":-12219292800000,"timezoneOffset":480,"year":-318},"lenient":true,"minimalDaysInFirstWeek":1,"time":{"date":6,"day":5,"hours":14,"minutes":47,"month":5,"seconds":58,"time":1212788878236,"timezoneOffset":420,"year":108},"timeInMillis":1212788878236,"timeZone":{"DSTSavings":3600000,"ID":"GMT-07:00","displayName":"GMT-07:00","rawOffset":-25200000}}
> net.sf.json.JSONException: java.lang.InstantiationException
>     at net.sf.json.JSONObject.toBean(JSONObject.java:304)
>     at net.sf.json.JSONObject.toBean(JSONObject.java:420)
>     at net.sf.json.JSONSerializer.toJava(JSONSerializer.java:69)
>
> ...
>
> Like I said, I am able to get the same code to work on other objects, such
> as Date objects, so what am I missing?  Is there a limitation on the types
> of objects that can be converted to JSONObject and back?
>
> Any help or pointers is greatly appreciated!
>
> Darlene
>
>