springboot的@ResponseBody处理null属性值和时间格式

1、继承处理类ObjectMapper

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;

public class JsonObjectMapper extends ObjectMapper {
    private static final long serialVersionUID = 1L;

    public JsonObjectMapper() {
        super();
        // 空值处理为空串
        this.getSerializerProvider().setNullValueSerializer(
                new JsonSerializer