Spring JSON prefix setup problems
I am configuring my Spring project to add JSON prefix )]}',\n
to overcome a common vulnerability. I tried to configure for this link , which throws an exception when starting the server. Please help me to solve this.
@Configuration
@EnableWebMvc
public Class WebAppConfig extends WebMvcConfigurationSupport
{
public void addPrefixJSON()
{
List<HttpMessageConverter<?>> converters = super.getMessageConverters();
MappingJackson2HttpMessageConverter convert = new MappingJackson2HttpMessageConverter();
convert.setPrefixJson(true);
converters.add(convert);
}
}
and i am getting follwing exception,
08:01:23,435 ERROR [org.springframework.web.context.ContextLoader]
(ServerService Thread Pool -- 68) Context initialization failed:
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'requestMappingHandlerMapping' defined in class path resource
[org/springframework/web/servlet/config/annotation/DelegatingWebMvcConfiguration.class]: Instantiation of bean failed; nested exception is
org.springframework.beans.factory.BeanDefinitionStoreException: Factory method [public
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping
org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport.requestMappingHandlerMapping()] threw exception; nested exception is
java.lang.ClassCastException: org.springframework.web.accept.ContentNegotiationManagerFactoryBean$$EnhancerByCGLIB$$6af53d42 cannot be cast to
org.springframework.web.accept.ContentNegotiationManager
I have included <mvc:annotation-driven />
in my spring-servlet.xml. Do we have any other manual methods for adding a prefix to an older version of Jackson, say Jackson 1.6?
Update:
The issue was fixed with Jackson 2.0 and I can view the prefix in the browser, however I cannot see the result from the angular end.
My config is like:
<mvc:annotation-driven content-negotiation-manager="contentManager">
<mvc:message-converters>
<bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
<property name="jsonPrefix" value=")]}',\n" />
</bean>
</mvc:message-converters>
</mvc:annotation-driven>
and the JSON output is
)]}',\n"{\"userName\":\"ABC\",\"emailId\":\"ABC@gmail.com\"}"
I am puzzled by this output, furthermore angular does not recognize the output and cannot read values from this object. Any help would be helpful. Thank you in advance.
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I am puzzled by this output, furthermore Angular does not recognize the output and cannot read the values of this object. Any help would be great.
the problem is with the Spring xml configuration: it seems that some character is escaped (possibly \ n escaped), so if you use
<mvc:annotation-driven content-negotiation-manager="contentManager">
<mvc:message-converters>
<bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
<property name="jsonPrefix" value=")]}',\n" />
</bean>
</mvc:message-converters>
</mvc:annotation-driven>
the prefix is a string)]} ', \ n instead of)]}', + newline. So the workaround I used was to create a class (like CustomMappingJackson2HttpMessageConverter) that extends the original org.springframework.http.converter.json.MappingJackson2HttpMessageConverter method and overrides the setJsonPrefix method like this:
public class CustomMappingJackson2HttpMessageConverter
extends org.springframework.http.converter.json.MappingJackson2HttpMessageConverter {
public CustomMappingJackson2HttpMessageConverter() {
super();
}
public CustomMappingJackson2HttpMessageConverter(ObjectMapper objectMapper) {
super(objectMapper);
}
@Override
public void setJsonPrefix(String jsonPrefix) {
super.setJsonPrefix(jsonPrefix+"\n");
}
}
and my config:
<mvc:annotation-driven>
<mvc:message-converters>
<bean class="mypackage.CustomMappingJackson2HttpMessageConverter">
<property name="jsonPrefix" value=")]}'," />
</bean>
</mvc:message-converters>
</mvc:annotation-driven>
this way you can save the configuration in xml file and allow proper JSON serialization / deserialization for Angular which needs 2 lines , the first is for )]} ' , and the second is for the JSON itself, this way Angular works great
JSON response in one line
1 )]}',\n["id":1,"name":"Marco"....]
JSON response in two lines
1 )]}',
2 ["id":1,"name":"Marco"....]
- AngularJS ver. 1.5.9
- Spring MVC ver. 4.2.8
hope this helps
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In Spring Lemon, simply configuring the bean as shown below instead of the above configuration:
@Bean
public MappingJackson2HttpMessageConverter mappingJackson2HttpMessageConverter() {
MappingJackson2HttpMessageConverter converter = new MappingJackson2HttpMessageConverter();
converter.setJsonPrefix(")]}',\n");
return converter;
}
An easy way to check if it will work is to look at the response data, for example. on the Network tab in chrome.
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You can XML-encode a newline character to allow customization exclusively in XML.
<mvc:annotation-driven>
<mvc:message-converters>
<bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
<property name="jsonPrefix" value=")]}', " />
</bean>
</mvc:message-converters>
</mvc:annotation-driven>
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