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Camel already supports a number of data formats to perform XML and JSON-related conversions, but all of them require a POJO either as an input (for marshalling) or produce a POJO as output (for unmarshallingun-marshaling). This data format provides the capability to convert from XML to JSON and viceversa directly, without stepping through intermediate POJOs.
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- marshalling => converting from XML to JSON
- unmarshalling un-marshaling => converting from JSON to XML.
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This data format supports the following options. You can set them via all DSLs. The defaults marked with with (*)
are determined by json-lib
, rather than the code of the data format itself. They are reflected reproduced here for convenience so that you don't have to dot back and forth with to avoid having to consult the json-lib
docs documentation directly.
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|| Name || Type || Default || Description ||
| {{encoding}} | {{String}} | UTF-8 \(*) | *Used when* {color:#008000}{*}unmarshalling{*}{color} *(JSON to XML conversion).* Sets the encoding for the call to [{{XMLSerializer.write()}}|http://json-lib.sourceforge.net/apidocs/net/sf/json/xml/XMLSerializer.html#write(net.sf.json.JSON, java.lang.String)] method, hence it is only used when producing XML. \\
When producing JSON, the encoding is determined by the input String being processed. If the conversion is performed on an InputStream, json-lib uses the platform's default encoding (e.g. determined by the {{file.encoding}} system property). |
| {{elementName}} | {{String}} | 'e' \(*) | *Used when* {color:#008000}{*}unmarshalling{*}{color}* (JSON to XML conversion).* Specifies the name of the XML elements representing each array element. See [json-lib doc|http://json-lib.sourceforge.net/snippets.html#JSONObject_to_XML_change_node_names]. |
| {{arrayName}} | {{String}} | 'a' \(*) | *Used when* {color:#008000}{*}unmarshalling{*}{color}* (JSON to XML conversion).* Specifies the name of the top-level XML element. \\
For example, when converting {{\[1, 2, 3\]}}, it will be output by default as {{Option | Type | Default | Description |
---|
encoding
| String
| UTF-8 (*)
| Used when un-marshaling (JSON to XML conversion). Sets the encoding for the call to XMLSerializer.write() method, hence it is only used when producing XML. However, when producing JSON, the encoding is determined by the input String being processed. If the conversion is performed on an InputStream , json-lib uses the platform's default encoding, e.g., determined by the file.encoding system property. | elementName
| String
| 'e' (*)
| Used when un-marshaling (JSON to XML conversion). Specifies the name of the XML elements representing each array element. See json-lib doc. | arrayName
| String
| 'a' (*)
| Used when un-marshaling (JSON to XML conversion). Specifies the name of the top-level XML element. For example, when converting: [1, 2, 3]
it is, by default, translated as: |
<a><e>1</e><e>2</e><e>3</e></a>
|
}}. ''. |
| {{rootName}} | {{String}} | none \(*) | *Used when* {color:#008000}{*}unmarshalling{*}{color}* (JSON to XML conversion).* When converting any JSON construct (object, array, null) to XML (unmarshalling), it specifies the name of the top-level element. \\
If not set, json-lib will use {{arrayName}} or {{objectName}} (default value: 'o', at the current time it is not configurable in this data format). If set to 'root', the JSON string \{ 'x': 'value1', 'y' : 'value2' \} would turn into {{. | rootName
| String
| none (*)
| Used when un-marshaling (JSON to XML conversion). When converting any JSON construct (object , array , null ) to XML (un-marshaling), this option specifies the name of the top-level XML element. If not set, json-lib will use arrayName or objectName (default value: o , at the current time it is not configurable in this data format). If set to root , the JSON string: { "x": "value1", "y" : "value2" }
is translated as: <root><x>value1</x><y>value2</y></root>
|
}}, otherwise the 'root' element would be named 'o'. |
| {{namespaceLenient}} | {{Boolean}} | false \(*) | *Used when* {color:#008000}{*}unmarshalling{*}{color}* (JSON to XML conversion).* According to the json-lib docs: "Flag to be tolerant to incomplete namespace prefixes." In most cases, json-lib automatically changes this flag at runtime to match the processing. |
| {{namespaceMappings}} | {{List<NamespacesPerElementMapping>}} | none | *Used when* {color:#008000}{*}unmarshalling{*}{color}* (JSON to XML conversion).* Binds namespace prefixes and URIs to specific JSON elements. {{NamespacesPerElementMapping}} is a wrapper around an element name + a Map of prefixes against URIs. \\ |
| {{expandableProperties}} | {{List<String>}} | none | *Used when* {color:#008000}{*}unmarshalling{*}{color}* (JSON to XML conversion).* With expandable properties, JSON array elements are converted to XML as a sequence of repetitive XML elements with the local name equal to the JSON key, for example: \{ number: 1,2,3 \}, normally converted to: {{otherwise the root element would be named o . | namespaceLenient
| Boolean
| false (*)
| Used when un-marshaling (JSON to XML conversion). According to the json-lib docs: "Flag to be tolerant to incomplete namespace prefixes." In most cases, json-lib automatically changes this flag at runtime to match the processing. | namespaceMappings
| List<NamespacesPerElementMapping>
| none
| Used when un-marshaling (JSON to XML conversion). Binds namespace prefixes and URIs to specific JSON elements. NamespacesPerElementMapping is a wrapper around an element name + a map of prefixes against URIs.
| expandableProperties
| List<String>
| none
| Used when un-marshaling (JSON to XML conversion). With expandable properties, JSON array elements are converted to XML as a sequence of repetitive XML elements with the local name equal to the JSON key. For example, the following JSON: { "number": 1,2,3 }
is normally translated as: <number><e>1</e><e>2</e><e>3</e></number>
|
}} (where e can be modified by setting elementName), would instead translate to {{where e can be modified by setting elementName . However, if number is set as an expandable property, it's translated as: <number>1</number><number>2</number><number>3</number>
|
}}, if "number" is set as an expandable property |
| {{typeHints}} | {{TypeHintsEnum}} | YES | *Used when* {color:#008000}{*}unmarshalling{*}{color}* (JSON to XML conversion).* Adds type hints to the resulting XML to aid conversion back to JSON. See documentation [here|http://json-lib.sourceforge.net/apidocs/net/sf/json/xml/XMLSerializer.html] for an explanation. {{TypeHintsEnum}} comprises the following values, which lead to different combinations of the underlying XMLSerializer's {{typeHintsEnabled}} and {{typeHintsCompatibility}} flags: \\
* {{TypeHintsEnum.NO}} => {{typeHintsEnabled}} = false
* {{TypeHintsEnum.YES}} => {{typeHintsEnabled}} = true, {{typeHintsCompatibility}} = true
* {{TypeHintsEnum.WITH_PREFIX}} => {{typeHintsEnabled}} = true, {{typeHintsCompatibility}} = false |
| {{forceTopLevelObject}} | {{Boolean}} | false \(*) | *Used when* {color:#333399}{*}marshalling{*}{color} *(XML to JSON conversion).* Determines whether the resulting JSON will start off with a top-most element whose name matches the XML root element. If disabled, XML string {{<a><x>1</x><y>2</y></a>}} turns into \{ 'x: '1', 'y': '2' \}. Otherwise, it turns into \{ 'a': \{ 'x: '1', 'y': '2' \}\}. |
| {{skipWhitespace}} | {{Boolean}} | false \(*) | *Used when* {color:#333399}{*}marshalling{*}{color}* (XML to JSON conversion).* Determines whether white spaces between XML elements will be regarded as text values or disregarded. |
| {{trimSpaces}} | {{Boolean}} | false \(*) | *Used when* {color:#333399}{*}marshalling{*}{color}* (XML to JSON conversion).* Determines whether leading and trailing white spaces will be omitted from String values. |
| {{skipNamespaces}} | {{Boolean}} | false \(*) | *Used when* {color:#333399}{*}marshalling{*}{color}* (XML to JSON conversion).* Signals whether namespaces should be ignored. By default they will be added to the JSON output using @xmlns elements. |
| {{removeNamespacePrefixes}} | {{Boolean}} | false \(*) | *Used when* {color:#333399}{*}marshalling{*}{color}* (XML to JSON conversion).* Removes the namespace prefixes from XML qualified elements, so that the resulting JSON string does not contain them. |
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Basic Usage with Java DSL
Explicitly instantiating the data format
| typeHints
| TypeHintsEnum
| YES
| Used when un-marshaling (JSON to XML conversion). Adds type hints to the resulting XML to aid conversion back to JSON. See documentation here for an explanation. TypeHintsEnum comprises the following values, which lead to different combinations of the underlying XMLSerializer's typeHintsEnabled and typeHintsCompatibility flags:
TypeHintsEnum.NO => typeHintsEnabled = false
TypeHintsEnum.YES => typeHintsEnabled = true , typeHintsCompatibility = true
TypeHintsEnum.WITH_PREFIX => typeHintsEnabled = true , typeHintsCompatibility = false
| forceTopLevelObject
| Boolean
| false (*)
| Used when marshaling (XML to JSON conversion). Determines whether the resulting JSON will start off with a top-most element whose name matches the XML root element. If this option is false , the XML string: <a><x>1</x><y>2</y></a>
is translated as: {"x": "1", "y": "2"}
If true , it's translated as: { "a": { "x": "1", "y": "2" }}
| skipWhitespace
| Boolean
| false (*)
| Used when marshaling (XML to JSON conversion). Determines whether white spaces between XML elements will be regarded as text values or disregarded. | trimSpaces
| Boolean
| false (*)
| Used when marshaling (XML to JSON conversion). Determines whether leading and trailing white spaces will be omitted from String values. | skipNamespaces
| Boolean
| false (*)
| Used when marshaling (XML to JSON conversion). Signals whether namespaces should be ignored. By default they will be added to the JSON output using @xmlns elements. | removeNamespacePrefixes
| Boolean
| false (*)
| Used when marshaling (XML to JSON conversion). Removes the namespace prefixes from XML qualified elements, so that the resulting JSON string does not contain them. |
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Basic Usage With the Java DSL
Explicitly Instantiating the DataFormat
Just instantiate the Just instantiate the XmlJsonDataFormat
from package org.apache.camel.dataformat.xmljson
. Make sure you have installed the camel-xmljson
feature (if running on OSGi) or that you've included included camel-xmljson-{version}.jar
and its transitive dependencies in your classpath.
Example, initialization with a default configuration:
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XmlJsonDataFormat xmlJsonFormat = new XmlJsonDataFormat();
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To tune the behaviour behavior of the data format as per the options above, use the appropriate setters:
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XmlJsonDataFormat xmlJsonFormat = new XmlJsonDataFormat();
xmlJsonFormat.setEncoding("UTF-8");
xmlJsonFormat.setForceTopLevelObject(true);
xmlJsonFormat.setTrimSpaces(true);
xmlJsonFormat.setRootName("newRoot");
xmlJsonFormat.setSkipNamespaces(true);
xmlJsonFormat.setRemoveNamespacePrefixes(true);
xmlJsonFormat.setExpandableProperties(Arrays.asList("d", "e"));
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Once you've instantiated the data formatthe DataFormat
is instantiated, the next step is to actually use the it from within it as a parameter to either of the marshal()
and /
unmarshal()
DSL elements:
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// fromFrom XML to JSON
from("direct:marshal")
.marshal(xmlJsonFormat)
.to("mock:json");
// fromFrom JSON to XML
from("direct:unmarshal")
.unmarshal(xmlJsonFormat)
.to("mock:xml");
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Defining the
...
DataFormat in-line
Alternatively, you can define the data format inline by using the xmljson()
DSL element.
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// fromFrom XML to JSON - inline dataformat
from("direct:marshalInline")
.marshal()
.xmljson()
.to("mock:jsonInline");
// fromFrom JSON to XML - inline dataformat
from("direct:unmarshalInline")
.unmarshal()
.xmljson()
.to("mock:xmlInline");
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If you wish, you can even pass in a Map<String, String> to the inline methods to provide custom options:
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Map<String, String> xmlJsonOptions = new HashMap<String, String>();
xmlJsonOptions.put(org.apache.camel.model.dataformat.XmlJsonDataFormat.ENCODING, "UTF-8");
xmlJsonOptions.put(org.apache.camel.model.dataformat.XmlJsonDataFormat.ROOT_NAME, "newRoot");
xmlJsonOptions.put(org.apache.camel.model.dataformat.XmlJsonDataFormat.SKIP_NAMESPACES, "true");
xmlJsonOptions.put(org.apache.camel.model.dataformat.XmlJsonDataFormat.REMOVE_NAMESPACE_PREFIXES, "true");
xmlJsonOptions.put(org.apache.camel.model.dataformat.XmlJsonDataFormat.EXPANDABLE_PROPERTIES, "d e");
// fromFrom XML to JSON - inline dataformat w/ options
from("direct:marshalInlineOptions")
.marshal()
.xmljson(xmlJsonOptions)
.to("mock:jsonInlineOptions");
// formFrom JSON to XML - inline dataformat w/ options
from("direct:unmarshalInlineOptions")
.unmarshal()
.xmljson(xmlJsonOptions).
.to("mock:xmlInlineOptions");
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Basic
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Usage with Spring or Blueprint DSL
Within the <dataFormats>
block, simply configure an xmljson
element with unique IDs:
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<dataFormats>
<xmljson id="xmljson"/>
<xmljson id="xmljsonWithOptions"
forceTopLevelObject="true"
trimSpaces="true"
rootName="newRoot"
skipNamespaces="true"
removeNamespacePrefixes="true"
expandableProperties="d e"/>
</dataFormats>
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Then you simply refer to the data format object within your <marshal/>
and { and <unmarshal/>
}} DSLs:
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<route>
<from uri="direct:marshal"/>
<marshal ref="xmljson"/>
<to uri="mock:json" />
</route>
<route>
<from uri="direct:unmarshalWithOptions"/>
<unmarshal ref="xmljsonWithOptions"/>
<to uri="mock:xmlWithOptions"/>
</route>
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Enabling XML DSL autocompletion for this component is easy: just refer to the appropriate Schema locations, depending on whether you're using Spring or Blueprint DSL. Remember that this data format is available from Camel 2.10 onwards, so . Therefore only schemas from that version onwards or later will include these new XML elements and attributes.
The syntax with Blueprint is identical to that of the Spring DSL. Just ensure the correct namespaces and and schemaLocations
are in use.
Namespace
...
Mappings
XML has namespaces to fully qualify elements and attributes; JSON doesn't. You need to take this into account when performing XML-JSON conversions.
To bridge the gap, Json-lib has an option to bind namespace declarations in the form of prefixes and namespace URIs to XML output elements while unmarshalling (i.e. un-marshaling, e.g., converting from JSON to XML).
For example, provided the following JSON string:
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{ '"pref1:a'": '"value1'", '"pref2:b'": '"value2" }
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you can ask Jsonask json-lib
to output namespace declarations on elements "elements pref1:a
" and " and pref2:b
" to bind the prefixes "pref1" and "pref2" prefixes pref1
and pref2
to specific namespace URIs.
To use this feature, simply create XmlJsonDataFormat.NamespacesPerElementMapping
objects and add them to the namespaceMappings
option (which is a List
).
The XmlJsonDataFormat.NamespacesPerElementMapping
holds an element name and a Map of [prefix => namespace URI]
. To facilitate mapping multiple prefixes and namespace URIs, the NamespacesPerElementMapping(String element, String pipeSeparatedMappings)
constructor takes a String-based pipe-separated sequence of of [prefix, namespaceURI]
pairs in the following way: |ns2|http://camel.apache.org/personalData|ns3|http://camel.apache.org/personalData2|
.
In order to define a default namespace, just leave the corresponding key field empty: |ns1|http://camel.apache.org/test1||http://camel.apache.org/default|
.
Binding namespace declarations to an element name = empty string will attach those namespaces to the root element.
The full code would look like thatcode for this is:
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XmlJsonDataFormat namespacesFormat = new XmlJsonDataFormat();
List<XmlJsonDataFormat.NamespacesPerElementMapping> namespaces = new ArrayList<XmlJsonDataFormat.NamespacesPerElementMapping>();
namespaces.add(new XmlJsonDataFormat.
NamespacesPerElementMapping("", "|ns1|http://camel.apache.org/test1||http://camel.apache.org/default|"));
namespaces.add(new XmlJsonDataFormat.
NamespacesPerElementMapping("NamespacesPerElementMapping("surname", "|ns2|http://camel.apache.org/personalData|" +
"ns3|http://camel.apache.org/personalData2|"));
namespacesFormat.setNamespaceMappings(namespaces);
namespacesFormat.setRootElement("person");
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Using the namespace bindings in the Java snippet above on the following JSON string:
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{ "name": "Raul", "surname": "Kripalani", "f": true, "g": null}
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Would yield the following XML:
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<person xmlns="http://camel.apache.org/default" xmlns:ns1="http://camel.apache.org/test1">
<f>true</f>
<g null="true"/>
<name>Raul</name>
<surname xmlns:ns2="http://camel.apache.org/personalData" xmlns:ns3="http://camel.apache.org/personalData2">Kripalani</surname>
</person>
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To use the XmlJson dataformat in your camel routes you need to add the following dependency to your pom.
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<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-xmljson</artifactId>
<version>x.x.x</version>
<!-- Use the same version as camel-core, but remember that this component is only available from Camel 2.10 -->
</dependency>
<!-- And also XOM must be included. XOM cannot be included by default due to an incompatible
license with ASF; so add this manually -->
<dependency>
<groupId>xom</groupId>
<artifactId>xom</artifactId>
<version>1.2.5</version>
</dependency> | xml | xml |
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-xmljson</artifactId>
<version>x.x.x</version>
<!-- Use the same version as camel-core, but remember that this component is only available from 2.10 onwards -->
</dependency>
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See Also