JSonPath
Available as of Camel 2.13
Camel supports JSonPath to allow using Expression or Predicate on json messages.
from("queue:books.new") .choice() .when().jsonpath("$.store.book[?(@.price < 10)]") .to("jms:queue:book.cheap") .when().jsonpath("$.store.book[?(@.price < 30)]") .to("jms:queue:book.average") .otherwise() .to("jms:queue:book.expensive")
Using XML configuration
If you prefer to configure your routes in your Spring XML file then you can use JSonPath expressions as follows
<camelContext id="camel" xmlns="http://camel.apache.org/schema/spring"> <route> <from uri="direct:start"/> <choice> <when> <jsonpath>$.store.book[?(@.price < 10)]</jsonpath> <to uri="mock:cheap"/> </when> <when> <jsonpath>$.store.book[?(@.price < 30)]</jsonpath> <to uri="mock:average"/> </when> <otherwise> <to uri="mock:expensive"/> </otherwise> </choice> </route> </camelContext>
Syntax
See the JSonPath project page for further examples.
Suppress exceptions
Available as of Camel 2.16
By default jsonpath will throw an exception if the json payload does not have a valid path accordingly to the configured jsonpath expression. In some use-cases you may want to ignore this in case the json payload contains optional data. Therefore you can set the option suppressExceptions to true to ignore this as shown:
from("direct:start") .choice() // use true to suppress exceptions .when().jsonpath("person.middlename", true) .to("mock:middle") .otherwise() .to("mock:other");
And in XML DSL:
<route> <from uri="direct:start"/> <choice> <when> <jsonpath suppressExceptions="true">person.middlename</jsonpath> <to uri="mock:middle"/> </when> <otherwise> <to uri="mock:other"/> </otherwise> </choice> </route>
This option is also available on the @JsonPath
annotation.
Inline Simple expressions
Available as of Camel 2.18
Its now possible to inlined Simple language expressions in the JSonPath expression using the simple syntax ${xxx}. An example is shown below:
from("direct:start") .choice() .when().jsonpath("$.store.book[?(@.price < ${header.cheap})]") .to("mock:cheap") .when().jsonpath("$.store.book[?(@.price < ${header.average})]") .to("mock:average") .otherwise() .to("mock:expensive");
In this example the Simple expression inlined is the headers with the cheap and average values to be used.
<route> <from uri="direct:start"/> <choice> <when> <jsonpath>$.store.book[?(@.price < ${header.cheap})]</jsonpath> <to uri="mock:cheap"/> </when> <when> <jsonpath>$.store.book[?(@.price < ${header.average})]</jsonpath> <to uri="mock:average"/> </when> <otherwise> <to uri="mock:expensive"/> </otherwise> </choice> </route>
JSonPath injection
You can use Bean Integration to invoke a method on a bean and use various languages such as JSonPath to extract a value from the message and bind it to a method parameter.
For example
public class Foo { @Consume(uri = "activemq:queue:books.new") public void doSomething(@JsonPath("$.store.book[*].author") String author, @Body String json) { // process the inbound message here } }
Encoding Detection
Since Camel version 2.16, the encoding of the JSON document is detected automatically, if the document is encoded in unicode (UTF-8, UTF-16LE, UTF-16BE, UTF-32LE, UTF-32BE ) as specified in RFC-4627. If the encoding is a non-unicode encoding, you can either make sure that you enter the document in String format to the JSONPath component or you can specify the encoding in the header "CamelJsonPathJsonEncoding" (JsonpathConstants.HEADER_JSON_ENCODING).
Dependencies
To use JSonPath in your camel routes you need to add the a dependency on camel-jsonpath which implements the JSonPath language.
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).
<dependency> <groupId>org.apache.camel</groupId> <artifactId>camel-jsonpath</artifactId> <version>x.x.x</version> </dependency>