Fix issue in MappingJacksonJsonView

Issue: SPR-10752

spring-webmvc/src/main/java/org/springframework/web/servlet/view/json/MappingJackson2JsonView.java

@@ -23,20 +23,21 @@ import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Set;
+
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
-import com.fasterxml.jackson.core.JsonEncoding;
-import com.fasterxml.jackson.core.JsonGenerator;
-import com.fasterxml.jackson.databind.ObjectMapper;
-import com.fasterxml.jackson.databind.SerializationFeature;
-
 import org.springframework.util.Assert;
 import org.springframework.util.CollectionUtils;
 import org.springframework.validation.BindingResult;
 import org.springframework.web.servlet.View;
 import org.springframework.web.servlet.view.AbstractView;
 
+import com.fasterxml.jackson.core.JsonEncoding;
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializationFeature;
+
 /**
  * Spring MVC {@link View} that renders JSON content by serializing the model for the current request
  * using <a href="http://jackson.codehaus.org/">Jackson 2.x's</a> {@link ObjectMapper}.
@@ -141,7 +142,7 @@ public class MappingJackson2JsonView extends AbstractView {
 	 * @see #setJsonPrefix
 	 */
 	public void setPrefixJson(boolean prefixJson) {
-		this.jsonPrefix = "{} && ";
+		this.jsonPrefix = prefixJson ? "{} && " : "";
 	}
 
 	/**

spring-webmvc/src/main/java/org/springframework/web/servlet/view/json/MappingJacksonJsonView.java

@@ -23,6 +23,7 @@ import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Set;
+
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
@@ -30,7 +31,6 @@ import org.codehaus.jackson.JsonEncoding;
 import org.codehaus.jackson.JsonGenerator;
 import org.codehaus.jackson.map.ObjectMapper;
 import org.codehaus.jackson.map.SerializationConfig;
-
 import org.springframework.util.Assert;
 import org.springframework.util.CollectionUtils;
 import org.springframework.validation.BindingResult;
@@ -141,7 +141,7 @@ public class MappingJacksonJsonView extends AbstractView {
 	 * @see #setJsonPrefix
 	 */
 	public void setPrefixJson(boolean prefixJson) {
-		this.jsonPrefix = "{} && ";
+		this.jsonPrefix = prefixJson ? "{} && " : "";
 	}
 
 	/**

spring-webmvc/src/test/java/org/springframework/web/servlet/view/json/MappingJackson2JsonViewTests.java

@@ -23,22 +23,11 @@ import java.util.HashSet;
 import java.util.Map;
 import java.util.Set;
 
-import com.fasterxml.jackson.core.JsonGenerator;
-import com.fasterxml.jackson.databind.JavaType;
-import com.fasterxml.jackson.databind.JsonMappingException;
-import com.fasterxml.jackson.databind.JsonSerializer;
-import com.fasterxml.jackson.databind.ObjectMapper;
-import com.fasterxml.jackson.databind.SerializerProvider;
-import com.fasterxml.jackson.databind.annotation.JsonSerialize;
-import com.fasterxml.jackson.databind.cfg.SerializerFactoryConfig;
-import com.fasterxml.jackson.databind.ser.BeanSerializerFactory;
-import com.fasterxml.jackson.databind.ser.SerializerFactory;
 import org.junit.Before;
 import org.junit.Test;
 import org.mozilla.javascript.Context;
 import org.mozilla.javascript.ContextFactory;
 import org.mozilla.javascript.ScriptableObject;
-
 import org.springframework.http.MediaType;
 import org.springframework.mock.web.test.MockHttpServletRequest;
 import org.springframework.mock.web.test.MockHttpServletResponse;
@@ -46,8 +35,19 @@ import org.springframework.ui.ModelMap;
 import org.springframework.validation.BindingResult;
 import org.springframework.web.servlet.View;
 
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.databind.JavaType;
+import com.fasterxml.jackson.databind.JsonMappingException;
+import com.fasterxml.jackson.databind.JsonSerializer;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializerProvider;
+import com.fasterxml.jackson.databind.annotation.JsonSerialize;
+import com.fasterxml.jackson.databind.cfg.SerializerFactoryConfig;
+import com.fasterxml.jackson.databind.ser.BeanSerializerFactory;
+import com.fasterxml.jackson.databind.ser.SerializerFactory;
+
 import static org.junit.Assert.*;
-import static org.mockito.BDDMockito.*;
+import static org.mockito.Mockito.*;
 
 /**
  * @author Jeremy Grelle
@@ -174,6 +174,14 @@ public class MappingJackson2JsonViewTests {
 	public void renderSimpleBeanPrefixed() throws Exception {
 		view.setPrefixJson(true);
 		renderSimpleBean();
+		assertTrue(response.getContentAsString().startsWith("{} && "));
+	}
+
+	@Test
+	public void renderSimpleBeanNotPrefixed() throws Exception {
+		view.setPrefixJson(false);
+		renderSimpleBean();
+		assertFalse(response.getContentAsString().startsWith("{} && "));
 	}
 
 	@Test

spring-webmvc/src/test/java/org/springframework/web/servlet/view/json/MappingJacksonJsonViewTests.java

@@ -39,14 +39,13 @@ import org.junit.Test;
 import org.mozilla.javascript.Context;
 import org.mozilla.javascript.ContextFactory;
 import org.mozilla.javascript.ScriptableObject;
-
 import org.springframework.mock.web.test.MockHttpServletRequest;
 import org.springframework.mock.web.test.MockHttpServletResponse;
 import org.springframework.ui.ModelMap;
 import org.springframework.validation.BindingResult;
 
 import static org.junit.Assert.*;
-import static org.mockito.BDDMockito.*;
+import static org.mockito.Mockito.*;
 
 /**
  * @author Jeremy Grelle
@@ -158,6 +157,14 @@ public class MappingJacksonJsonViewTests {
 	public void renderSimpleBeanPrefixed() throws Exception {
 		view.setPrefixJson(true);
 		renderSimpleBean();
+		assertTrue(response.getContentAsString().startsWith("{} && "));
+	}
+
+	@Test
+	public void renderSimpleBeanNotPrefixed() throws Exception {
+		view.setPrefixJson(false);
+		renderSimpleBean();
+		assertFalse(response.getContentAsString().startsWith("{} && "));
 	}
 
 	@Test