INT-4461: Support byte[] in #jsonPath

JIRA: https://jira.spring.io/browse/INT-4461

Convert `byte[]` to `String` using `URF-8` by default.

Add optional evaluate methods to JsonPathUtils with a Charset to use when
converting `byte[]` to `String`.

This is not currently exposed using SpEL. It can be done, but probably not worth
the effort until somebody asks for it.

**cherry-pick to 5.0.x, 4.3.x**

* Use `BAIS`

Author: garyrussell

spring-integration-core/src/main/java/org/springframework/integration/json/JsonPathUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2017 the original author or authors.
+ * Copyright 2013-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,6 +16,7 @@
 
 package org.springframework.integration.json;
 
+import java.io.ByteArrayInputStream;
 import java.io.File;
 import java.io.InputStream;
 import java.net.URL;
@@ -29,6 +30,7 @@
  * Note {@link #evaluate} is used as {@code #jsonPath()} SpEL function.
  *
  * @author Artem Bilan
+ * @author Gary Russell
  *
  * @since 3.0
  */
@@ -38,6 +40,9 @@ public static <T> T evaluate(Object json, String jsonPath, Predicate... predicat
 		if (json instanceof String) {
 			return JsonPath.read((String) json, jsonPath, predicates);
 		}
+		else if (json instanceof byte[]) {
+			return JsonPath.read(new ByteArrayInputStream((byte[]) json), jsonPath, predicates);
+		}
 		else if (json instanceof File) {
 			return JsonPath.read((File) json, jsonPath, predicates);
 		}

spring-integration-core/src/test/java/org/springframework/integration/json/JsonPathTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2017 the original author or authors.
+ * Copyright 2013-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -129,6 +129,11 @@ public void testInt3139JsonPathTransformer() throws IOException {
 		assertNotNull(receive);
 		assertEquals("Nigel Rees", receive.getPayload());
 
+		this.transformerInput.send(new GenericMessage<>(JSON.getBytes()));
+		receive = this.output.receive(10000);
+		assertNotNull(receive);
+		assertEquals("Nigel Rees", receive.getPayload());
+
 		this.transformerInput.send(new GenericMessage<File>(JSON_FILE));
 		receive = this.output.receive(1000);
 		assertNotNull(receive);
@@ -232,6 +237,12 @@ public void testJsonPathOnPayloadAnnotation() {
 		assertEquals("Nigel Rees", receive.getPayload());
 	}
 
+	@Test
+	public void testJsonInByteArray() throws Exception {
+		byte[] json = "{\"foo\":\"bar\"}".getBytes();
+		assertEquals("bar", JsonPathUtils.evaluate(json, "$.foo"));
+	}
+
 	@Configuration
 	@ImportResource("classpath:org/springframework/integration/json/JsonPathTests-context.xml")
 	@EnableIntegration