方法一：自定义消息转换器

@Configuration
public class WebMvcConfig extends WebMvcConfigurerAdapter{
    /**
     * 利用fastjson替换掉jackson
     * @param converters
     */
    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        super.configureMessageConverters(converters);
        FastJsonConfig fastJsonConfig = new FastJsonConfig();
        fastJsonConfig.setSerializerFeatures(SerializerFeature.PrettyFormat);
    }
}

方法二：在application.yml配置文件中

spring:
  jackson:
    default-property-inclusion: non_null

方法三：单DTO空值过滤，DTO上添加如下注解

import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;

@JsonIgnoreProperties(ignoreUnknown = true)   //忽略传参时其他无用字段
@JsonInclude(JsonInclude.Include.NON_EMPTY)    
@JsonInclude(JsonInclude.Include.NON_NULL) 
public class TestDTO {
	//返回值....
}