SpringBoot项目中处理返回json的null值(springboot项目为例)

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.boot.autoconfigure.condition.ConditionalOnMissingBean;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.context.annotation.Primary;import org.springframework.http.converter.json.Jackson2ObjectMapperBuilder;import java.io.IOException;@Configurationpublic class JsonConfig { @Bean @Primary @ConditionalOnMissingBean(ObjectMapper.class) public ObjectMapper jacksonObjectMapper(Jackson2ObjectMapperBuilder builder) {  ObjectMapper objectMapper = builder.createXmlMapper(false).build();  // 通过该方法对mapper对象进行设置，所有序列化的对象都将按改规则进行系列化  // Include.Include.ALWAYS 默认  // Include.NON_DEFAULT 属性为默认值不序列化  // Include.NON_EMPTY 属性为 空（""） 或者为 NULL 都不序列化，则返回的json是没有这个字段的。这样对移动端会更省流量  // Include.NON_NULL 属性为NULL 不序列化,就是为null的字段不参加序列化  //objectMapper.setSerializationInclusion(Include.NON_EMPTY);  // 字段保留，将null值转为""  objectMapper.getSerializerProvider().setNullValueSerializer(new JsonSerializer<Object>()  {   @Override   public void serialize(Object o, JsonGenerator jsonGenerator,         SerializerProvider serializerProvider)     throws IOException, JsonProcessingException   {    jsonGenerator.writeString("");   }  });  return objectMapper; }}

import java.io.Serializable;import com.fasterxml.jackson.annotation.JsonInclude;import com.fasterxml.jackson.annotation.JsonInclude.Include;public class RespObject implements Serializable {  private static final long serialVersionUID = -1560603887556641494L;  ....  @JsonInclude(Include.NON_NULL)  public Object respMsg;  @JsonInclude(Include.NON_NULL)  public Object respData;  ....}