@Test
	public void testJsonPropertyAccessor() throws Exception {
		FileSink sink = newFileSink().binary(true);
		HttpSource source = newHttpSource();

		stream().create(
				generateStreamName(),
				"%s | transform --expression=payload.foo.toString() | %s",
				source, sink);

		source.ensureReady().postData("{\"foo\":\"bar\"}");

		assertThat(sink, eventually(hasContentsThat(equalTo("bar"))));

	}
This tests that we have Json property access out of the box.
spring-xd-shell/src/test/java/org/springframework/xd/shell/command/AbstractSpelPropertyAccessorIntegrationTests.java