fortify Json Injection in java using GSON object - java

I want to deserialize json string by using Gson. I am getting a json from a web service ResponseEntity which I am converting it to String and then setting it to Model Object using gson library. On running the code on Fortify security, It is giving me Json injection error on below code with following message :
The data is written to a JSON stream. In this case the JSON is written
by fromJson()
Gson gson = new Gson();
MyObject obj = gson.fromJson(jsonString, MyObject.class);
Any solution?

Related

How to sanitize JSON string on deserialization to ObjectNode using Jackson

I have a JSON string from response to REST API which I am trying to deserialize into an ObjectNode in Jackson like below.
String response = webservice(...);
ObjectNode jsonObj = new ObjectMapper().readTree(response);
In our static scan of the source code, it found vulnerability to JSON injection that this call could allow an attacker to inject arbitrary elements or attributes into the JSON entity.
How can I make sure to protect against JSON injection?

How to parse xml into json with jackson

Can someone point me to the correct way to convert xml into json with jackson?
I have one service that accepts a post request with an xml body, I want to take that xml and send it to another service as a json.
I've seen some examples where people use an ObjectMapper, but ideally, I would have an interface ModelJsonView and then use the setMixInAnnotation() method to bind it to the corresponding model class.
Try this:
String xml = "<testName>Tester</testName><testValue>100</testValue>"
JSONObject xmlToJsonObject = XML.toJSONObject(xml);
ObjectMapper mapper = new ObjectMapper();
mapper.enable(SerializationFeature.INDENT_OUTPUT);
Object json = mapper.readValue(xmlToJsonObject.toString(), Object.class);
System.out.println(mapper.writerWithDefaultPrettyPrinter().writeValueAsString(json));
Include org.json and jackson jars.

How to parse json with java language keywords

Is there away to parse json with java keywords like class, case, default etc. to java object using Gson library?
The lines
Gson gson = new Gson();
MyObject myObject = gson.fromJson(json, MyObject.class);
simply parse json to my pojo, but I have key "class" in my json and I can't use the field "class" in java classes.
Yes, annotate your fields with #SerializedName, specifying the name of the field.
#SerializedName("class")
private String classField;
Or use a custom TypeAdapter.
You have to use annotations. These annotations tell Gson which JSON field maps to which Java property:
http://www.javacreed.com/gson-annotations-example/

Creating json object from POJO object in restful web service

I am developing a web application. I have database used by the web service. I want to send the same data to the web pages which are calling web service.
I get the data i.e. single row from the database by using hibernate and POJO classes(getColumn). Now I have object(POJO class) of the Table which represent single row of the database. For sending it back to the web pages (html, jsp), I need to convert it to the json object as my web service returns the json object.
How can I make Json object from POJO classes. There are many other ways to generate Json String but i want json object.
How can do this?
Thank you
You can use GSon to convert json object to java object
Link
to refer example.
Gson gson = new Gson();
//to get json object use toJson
String json = gson.toJson(obj);
//to get java object use fromJson
MyClass obj = gson.fromJson(jsonObj, MyClass.class);
or
jackson is also pretty fast and easy to use
private ObjectMapper mapper = new ObjectMapper();
JsonNode node = mapper.convertValue(YOUR POJO CLASS, JsonNode.class);
You can use Jackson and achieve this as above. GSON also does the job.
The way I use is with Google's Gson library. Very simple and powerful
Spring and Jackson as it is so simple. You can find a very basic example below Jackson/spring JSON example

Jackson JSON generator creates null JSON values for missing objects

I've started using Jackson as a JSON generator, as an alternative to google GSON. I've run into an issue where Jackson is generating object: null if the object is indeed null. GSON on the other hand generates NO entry in JSON, which is the behavior I want. Is there a way to stop Jackson from generating null object/value when an object is missing?
Jackson
ObjectMapper mapper = new ObjectMapper();
StringWriter sw = new StringWriter();
mapper.writeValue(sw, some_complex_object);
String jackson = sw.getBuffer().toString();
System.out.println("********************* START JACKSON JSON ****************************");
System.out.println(jackson);
System.out.println("********************* END JACKSON JSON ****************************");
generates this:
{"eatwithrustyspoon":{"urlList":null,"device":"iPad","os":"iPhone OS","peer_id":
and GSON looks like this:
Gson gson = new Gson();
String json = gson.toJson(some_complex_object);
System.out.println("********************* START GSON JSON ****************************");
System.out.println(json);
System.out.println("********************* END GSON JSON ****************************");
and it generates this (which is what I want - note that "urlList":null was not generated) :
{"eatwithrustyspoon":{"device":"iPad","os":"iPhone OS","peer_id"
From the Jackson FAQ:
Can I omit writing of Bean properties with null value? ("how to prevent writing of null properties", "how to suppress null values")
Yes. As per JacksonAnnotationSerializeNulls, you can use:
objectMapper.setSerializationInclusion(JsonSerialize.Inclusion.NON_NULL);
// or (for older versions):
objectMapper.configure(SerializationConfig.WRITE_NULL_PROPERTIES, false);
and voila, no more null values. Note that you MUST configure mapper before beans are serialized, since this setting may be cached along with serializers. So setting it too late might prevent change from taking effect.
my issue was bit different actually i was getting Null values for the properties of POJO class.
however i solved the problem by giving mapping to properties in my pojo class like this :
#JsonProperty("PROPERTY_NAME")
thought it may help someone :)
The following solution saved me.
objectMapper.setSerializationInclusion(Include.NON_NULL);

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