“未为类org.springframework.data.mongodb.core.convert.DefaultDbRefResolver$LazyLoadingInterceptor”找到序列化程序“

Question

我正在使用spring，在完成延迟加载后，我得到了错误的"No serializer found for class org.springframework.data.mongodb.core.convert.DefaultDbRefResolver$LazyLoadingInterceptor"。

我的域类是

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;

}

我浪费了很多时间，但我无法得到合适的答案？有人能帮我重新爱上它吗？提前感谢

Answer 1

为您的需求添加此配置代码

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;
    }

}

和

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();
    }
}

希望这能帮到你！

Answer 2

关闭该bean的序列化程序，因为延迟加载@DBRef只对实体列表有效，jackson会自动序列化@DBRef(懒惰=真)列表用户，而不序列化‘@DBRef(懒惰= true)用户。因此，您必须将其序列化，或者关闭该bean的序列化程序。