将数据中的null 替换成""

package com.lesiea.util;

import java.io.IOException;
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 org.springframework.stereotype.Component;

/**
 * Created by Duo Nuo on 2016/7/13.
 */
@Component
public class JsonObjectMapper extends ObjectMapper {
    public JsonObjectMapper() {
        super();
        // 空值处理为空串
        this.getSerializerProvider().setNullValueSerializer(new JsonSerializer