Spring Boot — Dynamically ignore fields while serializing Java Object to JSON

Lets consider we have a RestController class which has two endpoints to expose User & List<User>

User & UserController class

Since id & dob fields in User object are sensitive, we don’t want to expose them in our endpoints.

Jackson library provides @JsonIgnore & @JsonIgnoreProperties annotations to ignore fields while serializing

Here is a sample code

One catch with @JsonIgnore & @JsonIgnoreProperties annotations are — They expect field names in compile time itself. But what if our consumer want to ignore few fields dynamically based on their input ?

We can use MappingJacksonValue class to achieve the above requirement

Here is the sample code

Sample which uses MappingJacksonValue

Remember the below points

• Properties which are to be ignored is supplied to SimpleBeanPropertyFilter.serializeAllExcept(“id”, “dob”). This can be easily made dynamic based on user input
• Filter name mentioned in SimpleFilterProvider() .addFilter(“userFilter”, simpleBeanPropertyFilter) has to match filer name provided in @JsonFilter(“userFilter”) annotation on User class
• We need to return MappingJacksonValue instance instead of User or List<User> (Refer line 19 & line 34)

Thats all folks !

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