SpringMVC Jackson为null转化为空串处理

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

import java.io.IOException;

/**
 * @author Dongguabai
 * @date 2018/10/19 17:13
 */
public class JsonObjectMapper extends ObjectMapper {
    private static final long serialVersionUID = 1L;

    public JsonObjectMapper() {
        super();
        this.getSerializerProvider().setNullValueSerializer(new JsonSerializer