字段为null时，保存报错

Field error in object 'xxx' on field 'xxx': rejected value [null];

原因是数据库字段内容为空，从接口获取json对象值为null，重新提交时格式无法转换为对应的类型

方法一

@Configuration
public class JacksonConfig {
    @Bean
    @Primary
    @ConditionalOnMissingBean(ObjectMapper.class)
    public ObjectMapper jacksonObjectMapper(Jackson2ObjectMapperBuilder builder) {
        ObjectMapper objectMapper = builder.createXmlMapper(false).build();
        objectMapper.getSerializerProvider().setNullValueSerializer(new JsonSerializer<Object>() {
            @Override
            public void serialize(Object o, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException {
                jsonGenerator.writeString("");
            }
        });
        return objectMapper;
    }
}

方法二

spring.jackson.default-property-inclusion=NON_NULL

方法三

在实体类上添加注解

@JsonInclude(JsonInclude.Include.NON_NULL)