The transform processor is used by passing a SpEL expression. The expression should return the modified message or payload. For example, --expression=payload.toUpperCase().

This transform will convert all message payloads to upper case.

As part of the SpEL expression you can make use of the pre-registered JSON Path function. The syntax is #jsonPath(payload,'<json path expression>')

The transform processor has the following options:

expression

a SpEL expression used to transform messages (String, default: payload.toString())