Re: [json-lib-user] Casting classes
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Re: [json-lib-user] Casting classes
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From: Andres A. <aal...@ya...> - 2007-09-19 19:33:44
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Hi Jerry,=0A=0AA quick test reveals that your problem is indeed a bug but h=
as already=0Abeen fixed in the current development version, though an offic=
ial release has not yet been made. The following code shows that when the '=
nanos' property is being=0Aprocessed it will be skipped because the target =
bean doesn't have a=0APropertyDescriptor for it.=0A=0A=0A=0A{"value":0,"dat=
e":{"month":8,"day":3,"year":107,"nanos":0,"time":1190230433953,"seconds":5=
3,"timezoneOffset":300,"date":19,"hours":14,"minutes":33}}=0A=0A[07-09-19 1=
4:33:54] WARN [JSONObject:310] Property 'day' has no write method. SKIPPED=
.=0A=0A[07-09-19 14:33:54] WARN [JSONObject:395] Tried to assign property =
nanos:java.lang.Integer to bean of class java.util.Date=0A=0A[07-09-19 14:3=
3:54] WARN [JSONObject:310] Property 'timezoneOffset' has no write method.=
SKIPPED.=0A=0A=0A=0AThere is no need to define exclusions or filters throu=
gh JsonConfig (though you may do it to get rid of the warning).=0A=0AJson-l=
ib 2.1-SNAPSHOT is available from http://json-lib.sourceforge.net/m2/repo/s=
napshot/=0A=0AAn official release of 2.1 may take a little more time to all=
ow for a couple of feature requests to be finished.=0A=0A=0A=0ACheers,=0A=
=0AAndres =0A-------------------------------------------=0Ahttp://jroller.c=
om/page/aalmiray=0Ahttp://www.linkedin.com/in/aalmiray=0A--=0AWhat goes up,=
must come down. Ask any system administrator.=0AThere are 10 types of peop=
le in the world: Those who understand binary, and those who don't.=0ATo=
understand recursion, we must first understand recursion.=0A=0A----- Mensa=
je original ----=0ADe: Gerardo Blanco <Bla...@ld...>=0APara: Andr=
es Almiray <aal...@ya...>; jso...@li...=0AEnvi=
ado: mi=E9rcoles, 19 de septiembre, 2007 11:36:42=0AAsunto: Re: [json-lib-u=
ser] Casting classes=0A=0A=0A=0A =0A=0A=0A=0A=0A=0A=0A=0AI'm using version =
2. =0A=0A=0A =0A=0A=0AThe exception I got was =0A=0A=0A =0A=0A=0Anet.sf.jso=
n.JSONException: Error while setting property=3Dnanos typeclass java.lang.I=
ntegerHere's the code:JSONObject jsonObject =3D JSONObject.fromObject(myBea=
n);System.out.println(myBean);MyBean b =3D (MyBean) JSONObject.toBean(jsonO=
bject, MyBean.class);=0ASystem.out.println(b); Here's the bean def:import j=
ava.util.Date;public class MyBean {...@Column(name=3D"PS_EFFECTIVE_DATE")=
=0ADate psEffectiveDate;=0A...public Date getPsEffectiveDate() {=0A retur=
n psEffectiveDate;=0A}=0A...public void setPsEffectiveDate(Date psEffective=
Date) {=0A this.psEffectiveDate =3D psEffectiveDate;=0A }...}And this is t=
he section of the JSON string that shows the object:,"psEffectiveDate":{"mo=
nth":0,"day":1,"year":0,"nanos":0,"time":-2208963600000,"seconds":0,"timezo=
neOffset":420,"date":1,"hours":0,"minutes":0},If I comment out the last two=
lines in the code (where I create a new MyBean, etc), the whole process wo=
rks fine. If I leave them, it fails when creating the bean b. Any comments?=
-------------------------------------------------------=0AGerardo (Jerry) =
R. Blanco =0ASoftware Engineer=0ALDS Platform Team=0A(801) 240-6978=0ABlanc=
oG...@ld... =0A------------------------------------------------------=
-=0A"I am endeavoring, ma'am, to construct a mnemonic memory circuit, using=
stone knives and bearskins." -- Spock=0A>>> Andres Almiray <aalmiray@yahoo=
.com> 9/19/2007 9:41 AM >>>=0A=0A=0A=0A=0A=0AHi Jerry,=0ASince version 0.9 =
(I think) there is the option to specify a set of exclusions that will let =
filter out some properties when using JSONObject.fromObject(), in your case=
=0A=0A/* available in json-lib 1.x */=0AJSON json =3D JSONSerializer.toJSON=
( bean, new String[]{ "nanos"} );=0AJSONSerializer jsonSerializer =3D new J=
SONSerializer();=0AjsonSerializer.setRootClass( Bean.class );=0ABean bean =
=3D (Bean) jsonSerializer.toJava( json );=0A=0A/* the following is from 2.1=
-SNAPSHOT */=0AJsonConfig jsonConfig =3D new JsonConfig();=0AjsonConfig.set=
Excludes( new String[]{ "nanos"} );=0AJSON json =3D JSONSerializer.toJSON( =
bean, jsonConfig );=0A...=0AjsonConfig.setRootClass( Bean.class );=0ABean b=
ean =3D (Bean) JSONSerializer.toJava( json, jsonConfig );=0A =0AIn 2.1-SNAP=
SHOT there is also the option to setup filters that will be enabled when se=
rializing to JSON and transforming back to Java=0A=0AI'm quite surprised th=
at 'nanos' gave caused a problem because the code should check if there is =
a PropertyDescriptor that matches the target class and property, if so it w=
ill also check if it has a proper writeMethod. Which version are you using?=
=0A=0ARegards,=0AAndres=0A=0A =0A------------------------------------------=
-=0Ahttp://jroller.com/page/aalmiray=0Ahttp://www.linkedin.com/in/aalmiray=
=0A--=0AWhat goes up, must come down. Ask any system administrator.=0AThere=
are 10 types of people in the world: Those who understand binary, and thos=
e who don't.=0ATo understand recursion, we must first understand recurs=
ion.=0A=0A=0A=0A=0A=0A----- Mensaje original ----=0ADe: Gerardo Blanco <Bla=
nc...@ld...>=0APara: jso...@li...=0AEnviado:=
mi=E9rcoles, 19 de septiembre, 2007 10:30:45=0AAsunto: [json-lib-user] Cas=
ting classes=0A=0A=0A=0AHi, =0A=0A=0A =0A=0A=0AI'm doing the following:=0A=
=0A=0A =0A=0A=0A1) Run a Hibernate query to populate a bean=0A=0A=0A2) usin=
g JSONObject.fromObject(bean)=0A=0A=0A3) using JSONObject.toBean()=0A=0A=0A=
=0A=0A=0AThe problem is that the bean contains a java.util.Date. Hibernate=
casts that to a java.sql.Timestamp, which extends java.util.Date, so Hiber=
nate is complying with the contract.=0A=0A=0AWhen I create my JSONObject, t=
he method fromObject grabs everything the Timestamp contains, including 'na=
nos' (for nanoseconds). That property belongs to Timestamp.=0A=0A=0A =0A=0A=
=0AWhen toBean is called, it doesn't know what to do with 'nanos' because i=
t is introspecting java.util.Date.=0A=0A=0A =0A=0A=0AI know I can code arou=
nd this issue by modifying my getters/setters, but my questions is: =0A=0A=
=0Ashould this behaviour be caught (and provided for) by JSON-lib somehow?=
=0A=0A=0A =0A=0A=0AWhat if we had JSONObject.fromObject(bean, Bean.class)? =
That way JSONObject.fromObject would introspect the class, and only include=
fields for the getters/setters for the actual class, instead of extended c=
lasses that might be present.=0A=0A=0A =0A=0A=0AThanks.=0A=0A=0AJerry. =0A=
=0A=0A =0A=0A=0A-------------------------------------------------------=0AG=
erardo (Jerry) R. Blanco =0ASoftware Engineer=0ALDS Platform Team=0A(801) 2=
40-6978=0AB...@ld... =0A---------------------------------------=
----------------=0A"I am endeavoring, ma'am, to construct a mnemonic memory=
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