Add JSONP support for MappingJackson2MessageConverter

Issue: SPR-9899

spring-web/src/main/java/org/springframework/http/converter/json/MappingJackson2HttpMessageConverter.java

@@ -249,15 +249,27 @@ public class MappingJackson2HttpMessageConverter extends AbstractHttpMessageConv
 			if (this.jsonPrefix != null) {
 				jsonGenerator.writeRaw(this.jsonPrefix);
 			}
+			Class<?> serializationView = null;
+			String jsonpFunction = null;
 			if (object instanceof MappingJacksonValue) {
-				MappingJacksonValue valueHolder = (MappingJacksonValue) object;
-				object = valueHolder.getValue();
-				Class<?> serializationView = valueHolder.getSerializationView();
+				MappingJacksonValue container = (MappingJacksonValue) object;
+				object = container.getValue();
+				serializationView = container.getSerializationView();
+				jsonpFunction = container.getJsonpFunction();
+			}
+			if (jsonpFunction != null) {
+				jsonGenerator.writeRaw(jsonpFunction + "(" );
+			}
+			if (serializationView != null) {
 				this.objectMapper.writerWithView(serializationView).writeValue(jsonGenerator, object);
 			}
 			else {
 				this.objectMapper.writeValue(jsonGenerator, object);
 			}
+			if (jsonpFunction != null) {
+				jsonGenerator.writeRaw(");");
+				jsonGenerator.flush();
+			}
 		}
 		catch (JsonProcessingException ex) {
 			throw new HttpMessageNotWritableException("Could not write JSON: " + ex.getMessage(), ex);

spring-web/src/main/java/org/springframework/http/converter/json/MappingJacksonValue.java

@@ -17,44 +17,83 @@
 package org.springframework.http.converter.json;
 
 /**
- * Holds an Object to be serialized via Jackson together with a serialization
- * view to be applied.
+ * A simple holder for the POJO to serialize via
+ * {@link org.springframework.http.converter.json.MappingJackson2HttpMessageConverter
+ * MappingJackson2HttpMessageConverter} along with further serialization
+ * instructions to be passed in to the converter.
+ *
+ * <p>On the server side this wrapper is added with a
+ * {@code ResponseBodyInterceptor} after content negotiation selects the
+ * converter to use but before the write.
+ *
+ * <p>On the client side, simply wrap the POJO and pass it in to the
+ * {@code RestTemplate}.
  *
  * @author Rossen Stoyanchev
  * @since 4.1
- *
- * @see com.fasterxml.jackson.annotation.JsonView
  */
 public class MappingJacksonValue {
 
-	private final Object value;
+	private Object value;
 
-	private final Class<?> serializationView;
+	private Class<?> serializationView;
+
+	private String jsonpFunction;
 
 
 	/**
-	 * Create a new instance.
+	 * Create a new instance wrapping the given POJO to be serialized.
 	 * @param value the Object to be serialized
-	 * @param serializationView the view to be applied
 	 */
-	public MappingJacksonValue(Object value, Class<?> serializationView) {
+	public MappingJacksonValue(Object value) {
 		this.value = value;
-		this.serializationView = serializationView;
 	}
 
 
 	/**
-	 * Return the value to be serialized.
+	 * Modify the POJO to serialize.
+	 */
+	public void setValue(Object value) {
+		this.value = value;
+	}
+
+	/**
+	 * Return the POJO that needs to be serialized.
 	 */
 	public Object getValue() {
 		return this.value;
 	}
 
+	/**
+	 * Set the serialization view to serialize the POJO with.
+	 * @see com.fasterxml.jackson.databind.ObjectMapper#writerWithView(Class)
+	 * @see com.fasterxml.jackson.annotation.JsonView
+	 */
+	public void setSerializationView(Class<?> serializationView) {
+		this.serializationView = serializationView;
+	}
+
 	/**
 	 * Return the serialization view to use.
+	 * @see com.fasterxml.jackson.databind.ObjectMapper#writerWithView(Class)
+	 * @see com.fasterxml.jackson.annotation.JsonView
 	 */
 	public Class<?> getSerializationView() {
 		return this.serializationView;
 	}
 
+	/**
+	 * Set the name of the JSONP function name.
+	 */
+	public void setJsonpFunction(String functionName) {
+		this.jsonpFunction = functionName;
+	}
+
+	/**
+	 * Return the configured JSONP function name.
+	 */
+	public String getJsonpFunction() {
+		return this.jsonpFunction;
+	}
+
 }