Getting error “No serializer found for class org.springframework.data.mongodb.core.convert.DefaultDbRefResolver$LazyLoadingInterceptor”

问题

I am using spring data mongodb,after doing lazy loading true i am getting error "No serializer found for class org.springframework.data.mongodb.core.convert.DefaultDbRefResolver$LazyLoadingInterceptor".

My domain class is

public class Preference extends BaseEntity {

    @DBRef(lazy = true)
    User user;

    MetadataEnum preferenceType;


    public User getUser() {
        return user;
    }

    public void setUser(User user) {
        this.user = user;
    }


    public MetadataEnum getPreferenceType() {
        return preferenceType;
    }


    public void setPreferenceType(MetadataEnum preferenceType) {
        this.preferenceType = preferenceType;
    }


    public List<Subtype> getSubtypes() {
        return subtypes;
    }


    public void setSubtypes(List<Subtype> subtypes) {
        this.subtypes = subtypes;
    }

    List<Subtype> subtypes = new ArrayList<Subtype>();


    boolean enableSearch;

}

i have wasted my time alot,but i am unable to get suitable answer of it? anyone can help me to reslove it? Thanks in advance

回答1:

Add this configuration code for your requirement

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.mongodb.core.convert.LazyLoadingProxy;

import com.fasterxml.jackson.core.Version;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.module.SimpleModule;

@Configuration
public class LazyLoadingSerializationConfig {

    @Bean
    public ObjectMapper objectMapper() {

        ObjectMapper om = new ObjectMapper();
        final SimpleModule module = new SimpleModule("<your entity>", new Version(1, 0, 0,null));

        module.addSerializer(LazyLoadingProxy.class, new LazyLoadingSerializer());
        om.registerModule(module);

        return om;
    }

}

and

import java.io.IOException;

import org.springframework.data.mongodb.core.convert.LazyLoadingProxy;

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.SerializerProvider;

public class LazyLoadingSerializer extends JsonSerializer<LazyLoadingProxy> {

    @Override
    public void serialize(LazyLoadingProxy value, JsonGenerator jgen,
        SerializerProvider provider) throws IOException,
        JsonProcessingException {

        jgen.writeStartObject();
        jgen.writeStringField("id", value.toDBRef().getId().toString());
        jgen.writeEndObject();
    }
}

Hope this may help you!

回答2:

switch off serializer for that bean because lazy loading with @DBRef works for list of entity only , jackson automatically serialize the @DBRef(lazy = true) List user but not for '@DBRef(lazy = true) User user. So you have to serialize it mannually or switch off serializer for that bean'.

来源：https://stackoverflow.com/questions/31914090/getting-error-no-serializer-found-for-class-org-springframework-data-mongodb-co

标签

mongodb

spring-data-mongodb