Hi Richard Remember to add a note in the documentation that this is available as of Camel 2.10.
On Mon, Apr 2, 2012 at 10:12 PM, <conflue...@apache.org> wrote: > JSON <https://cwiki.apache.org/confluence/display/CAMEL/JSON> Page * > edited* by Richard > Kettelerij<https://cwiki.apache.org/confluence/display/~rkettelerij> > *Comment:* CAMEL-5135 > > Changes (2) > ... > By default Camel uses the XStream library. > > h3. Using JSson data format with the XStream library > {code} > // lets turn Object messages into json then send to MQSeries > ... > {code} > > h3. Excluding POJO fields from marshalling > When marshalling a POJO to JSON you might want to exclude certain fields > from the JSON output. With Jackson you can use [JSON views| > http://wiki.fasterxml.com/JacksonJsonViews] to accomplish this. First > create one or more marker classes. > {snippet:id=marker|lang=java|url=camel/trunk/components/camel-jackson/src/test/java/org/apache/camel/component/jackson/Views.java} > > > Use the marker classes with the {{@JsonView}} annotation to > include/exclude certain fields. The annotation also works on getters. > {snippet:id=jsonview|lang=java|url=camel/trunk/components/camel-jackson/src/test/java/org/apache/camel/component/jackson/TestPojoView.java} > > > Finally use the Camel {{JacksonDataFormat}} to marshall the above POJO to > JSON. > {snippet:id=format|lang=java|url=camel/trunk/components/camel-jackson/src/test/java/org/apache/camel/component/jackson/JacksonMarshalViewTest.java} > > > Note that the weight field in missing in the resulting JSON: > {code} > {"age":30, "height":190} > {code} > > The GSON library supports a similar feature through the notion of > [ExclusionStrategies| > http://google-gson.googlecode.com/svn/trunk/gson/docs/javadocs/com/google/gson/ExclusionStrategy.html]: > > {snippet:id=strategy|lang=java|url=camel/trunk/components/camel-gson/src/test/java/org/apache/camel/component/gson/GsonMarshalExclusionTest.java} > > > The {{GsonDataFormat}} accepts an {{ExclusionStrategy}} in its > constructor: > {snippet:id=format|lang=java|url=camel/trunk/components/camel-gson/src/test/java/org/apache/camel/component/gson/GsonMarshalExclusionTest.java} > > The line above will exclude fields annotated with {{@ExcludeAge}} during > JSON marshalling. > > h3. Dependencies for XStream > > ... > Full Content > JSON > > JSON is a Data > Format<https://cwiki.apache.org/confluence/display/CAMEL/Data+Format>to > marshal and unmarshal Java objects to and from > JSON <http://www.json.org/>. > > In Camel 1.6 its only the XStream library that is supported and its > default. > > In Camel 2.0 we added support for more libraries: > Camel provides integration with two popular JSon libraries: > > - The XStream library <http://xstream.codehaus.org/> and Jettsion > <http://jettison.codehaus.org/> > - The Jackson library <http://xircles.codehaus.org/projects/jackson> > - *Camel 2.10:* The GSon library<http://code.google.com/p/google-gson/> > > By default Camel uses the XStream library. > Using Json data format with the XStream library > > // lets turn Object messages into json then send to > MQSeriesfrom("activemq:My.Queue"). > marshal().json(). > to("mqseries:Another.Queue"); > > Using Json data format with the Jackson library > > // lets turn Object messages into json then send to > MQSeriesfrom("activemq:My.Queue"). > marshal().json(JsonLibrary.Jackson). > to("mqseries:Another.Queue"); > > Using Json data format with the GSON library > > // lets turn Object messages into json then send to > MQSeriesfrom("activemq:My.Queue"). > marshal().json(JsonLibrary.Gson). > to("mqseries:Another.Queue"); > > Using Json in Spring DSL > > When using Data > Format<https://cwiki.apache.org/confluence/display/CAMEL/Data+Format>in > Spring DSL you need to declare the data formats first. This is done in > the *DataFormats* XML tag. > > <dataFormats> > <!-- here we define a Json data format with the id jack and that > it should use the TestPojo as the class type when > doing unmarshal. The unmarshalTypeName is optional, if not > provided Camel will use a Map as the type --> > <json id="jack" library="Jackson" > unmarshalTypeName="org.apache.camel.component.jackson.TestPojo"/> > </dataFormats> > > And then you can refer to this id in the route: > > <route> > <from uri="direct:back"/> > <unmarshal ref="jack"/> > <to uri="mock:reverse"/> > </route> > > Excluding POJO fields from marshalling > > When marshalling a POJO to JSON you might want to exclude certain fields > from the JSON output. With Jackson you can use JSON > views<http://wiki.fasterxml.com/JacksonJsonViews>to accomplish this. First > create one or more marker classes. > > public class Views { > > static class Weight { } > static class Age { } > } > > Use the marker classes with the @JsonView annotation to include/exclude > certain fields. The annotation also works on getters. > > @JsonView(Views.Age.class)private int age = 30; > private int height = 190; > > @JsonView(Views.Weight.class)private int weight = 70; > > Finally use the Camel JacksonDataFormat to marshall the above POJO to > JSON. > > JacksonDataFormat ageViewFormat = new > JacksonDataFormat(TestPojoView.class, Views.Age.class); > from("direct:inPojoAgeView").marshal(ageViewFormat); > > from("direct:backPojoAgeView").unmarshal(ageViewFormat).to("mock:reversePojoAgeView"); > > JacksonDataFormat weightViewFormat = new > JacksonDataFormat(TestPojoView.class, Views.Weight.class); > > from("direct:inPojoWeightView").marshal(weightViewFormat); > > from("direct:backPojoWeightView").unmarshal(weightViewFormat).to("mock:reversePojoWeightView"); > } > }; > } > > } > > Note that the weight field in missing in the resulting JSON: > > {"age":30, "height":190} > > The GSON library supports a similar feature through the notion of > ExclusionStrategies<http://google-gson.googlecode.com/svn/trunk/gson/docs/javadocs/com/google/gson/ExclusionStrategy.html> > : > > /** > * Strategy to exclude {@link ExcludeAge} annotated fields > */protected static class AgeExclusionStrategy implements ExclusionStrategy { > > @Override > public boolean shouldSkipField(FieldAttributes f) { > return f.getAnnotation(ExcludeAge.class) != null; > } > > @Override > public boolean shouldSkipClass(Class<?> clazz) { > return false; > } > } > > The GsonDataFormat accepts an ExclusionStrategy in its constructor: > > GsonDataFormat ageExclusionFormat = new > GsonDataFormat(TestPojoExclusion.class, new AgeExclusionStrategy()); > > The line above will exclude fields annotated with @ExcludeAge during > JSON marshalling. > Dependencies for XStream > > To use JSON in your camel routes you need to add the a dependency on * > camel-xstream* which implements this data format. > > If you use maven you could just add the following to your pom.xml, > substituting the version number for the latest & greatest release (see the > download page for the latest > versions<https://cwiki.apache.org/confluence/display/CAMEL/Download> > ). > > <dependency> > <groupId>org.apache.camel</groupId> > <artifactId>camel-xstream</artifactId> > <version>2.0</version></dependency> > > Dependencies for Jackson > > To use JSON in your camel routes you need to add the a dependency on * > camel-jackson* which implements this data format. > > If you use maven you could just add the following to your pom.xml, > substituting the version number for the latest & greatest release (see the > download page for the latest > versions<https://cwiki.apache.org/confluence/display/CAMEL/Download> > ). > > <dependency> > <groupId>org.apache.camel</groupId> > <artifactId>camel-jackson</artifactId> > <version>2.0</version></dependency> > > Dependencies for GSON > > To use JSON in your camel routes you need to add the a dependency on * > camel-gson* which implements this data format. > > If you use maven you could just add the following to your pom.xml, > substituting the version number for the latest & greatest release (see the > download page for the latest > versions<https://cwiki.apache.org/confluence/display/CAMEL/Download> > ). > > <dependency> > <groupId>org.apache.camel</groupId> > <artifactId>camel-gson</artifactId> > <version>2.10</version></dependency> > > Change Notification > Preferences<https://cwiki.apache.org/confluence/users/viewnotifications.action> > View Online <https://cwiki.apache.org/confluence/display/CAMEL/JSON> | View > Changes<https://cwiki.apache.org/confluence/pages/diffpagesbyversion.action?pageId=101227&revisedVersion=6&originalVersion=5>| > Add > Comment<https://cwiki.apache.org/confluence/display/CAMEL/JSON?showComments=true&showCommentArea=true#addcomment> > -- Claus Ibsen ----------------- CamelOne 2012 Conference, May 15-16, 2012: http://camelone.com FuseSource Email: cib...@fusesource.com Web: http://fusesource.com Twitter: davsclaus, fusenews Blog: http://davsclaus.blogspot.com/ Author of Camel in Action: http://www.manning.com/ibsen/
