@JsonFilter throws “JsonMappingException: Can not resolve BeanPropertyFilter”

问题

Is it possible to selectively determine when the @JsonFilter annotation gets used at runtime?

I'm getting JsonMappingException exception (see below) when I don't provide the filter.

Background:

I learned from a recent StackOverflow post that I can use @JsonFilter to dynamically filter the bean properties getting serialized. This works great. After adding @JsonFilter("apiFilter") to my domain class and with the addition of this code in my jax-rs service (using the CXF implementation), I am able to dynamically filter the properties returned by my RESTful API:

// shortened for brevity
FilterProvider filters = new SimpleFilterProvider().addFilter("apiFilter", SimpleBeanPropertyFilter.filterOutAllExcept(filterProperties));

return mapper.filteredWriter(filters).writeValueAsString(user);

The problem is there are different service calls where I don't want to apply the filter at all. In those cases I want to return the entire domain class without filtering any properties. In the case where I just try to return the domain class I'm getting an exception as follows:

Caused by: org.codehaus.jackson.map.JsonMappingException: Can not resolve BeanPropertyFilter with id 'apiFilter'; no FilterProvider configured

at org.codehaus.jackson.map.ser.BeanSerializer.findFilter(BeanSerializer.java:252)
at org.codehaus.jackson.map.ser.BeanSerializer.serializeFieldsFiltered(BeanSerializer.java:216)
at org.codehaus.jackson.map.ser.BeanSerializer.serialize(BeanSerializer.java:140)

回答1:

I think you could trick the filtered writer defining an empty serialize filter for the cases where you want all the properties seralized:

FilterProvider filters = new SimpleFilterProvider().addFilter("apiFilter", SimpleBeanPropertyFilter.serializeAllExcept(emptySet));

This way, when the engine looks for the "apiFilter" filter defined at the @JsonFilter anotation, it finds it, but it will not have any effect (as will serialize all the properties).

EDIT Also, you can call the factory method writer() instead of filteredWriter():

ObjectWriter writer=null;
if(aplyFilter) {
    FilterProvider filters = new SimpleFilterProvider().addFilter("apiFilter", SimpleBeanPropertyFilter.filterOutAllExcept(filterProperties));
    writer=mapper.filteredWriter(filters);
} else {
   writer=mapper.writer();
}

return writer.writeValueAsString(user);

I think this last solution is way cleaner, and indeed better.

回答2:

I know it's already been answered but for any newcommers Jackson has actually added the ability to not fail on missing filters (JACKSON-650):
You just need to call SimpleFilterProvider.setFailOnUnknownId(false) and you won't get this exception.

回答3:

For Spring Boot / Jackson configuration just add:

@Configuration 
public class JacksonConfiguration { 
    public JacksonConfiguration(ObjectMapper objectMapper) { 
        objectMapper.setFilterProvider(new SimpleFilterProvider().setFailOnUnknownId(false)); 
    } 
}

回答4:

I had a similar issue getting the same Exception, but the accepted answer didn't really help in my case. Here's the solution that worked for me:

In my setup I was using a custom JacksonSerializer like this:

@JsonSerialize(using = MyCustomSerializer.class)
private Object someAttribute;

And that serializer was implemented like this:

public class MyCustomSerializer extends JsonSerializer<Object> {
  @Override
  public void serialize(Object o, JsonGenerator jgen, SerializerProvider provider) throws IOException, JsonProcessingException {
    if (o != null) {
      jgen.writeObject(o);
    }
  }
}

The problem with this is, that as long as you don't use any filters, it works. It also works if you serialize primitives, so for instance if you use jgen.writeString(..). If you use filters, that code is wrong, because the filters are stored somewhere inside of the SerializerProvider, not in the JsonGenerator. If in that case you use the jsongenerator directly, a new SerializerProvider, that doesn't know about the filters, is created internally. So instead of the shorter jgen.writeObject(o) you need to call provider.defaultSerializeValue(o, jgen). That will ensure that the filters don't get lost and can be applied.

来源：https://stackoverflow.com/questions/9382094/jsonfilter-throws-jsonmappingexception-can-not-resolve-beanpropertyfilter

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