解决Long类型web前端精度丢失问题
1 背景
后端编号采用分布式Id长度19位,如:1564586000854925325,如果直接返回前端Long类型会出现最后1位精度缺失问题,前端接收的数字为:1564586000854925320
2 原因
Java中Long的取值范围:
-9223372036854775808到9223372036854775807(即-2^64“ 到”2^64-1)
JavaScript中的Number取值范围:
-9007199254740992 到9007199254740991 (即-2^53 到2^53-1)
3 解决方法
将Long类型转成String
3.1 spring-boot程序方法1
@Configuration
public class MappingJackson2HttpMessageConverterConfig {
@Bean
public MappingJackson2HttpMessageConverter mappingJackson2HttpMessageConverter() {
MappingJackson2HttpMessageConverter converter = new MappingJackson2HttpMessageConverter();
ObjectMapper objectMapper = new ObjectMapper();
// 反序列化忽略未知属性
objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES,false);
// 全局转化Long类型为String,解决Jackson序列化时web精度确实问题
SimpleModule simpleModule=new SimpleModule();
simpleModule.addSerializer(Long.class, ToStringSerializer.instance);
simpleModule.addSerializer(Long.TYPE, ToStringSerializer.instance);
objectMapper.registerModule(simpleModule);
converter.setObjectMapper(objectMapper);
return converter;
}
}
3.2 spring-boot程序方法2
@Configuration
public class JacksonConfig {
/**
* Jackson全局转化long类型为String,解决long类型缺失精度问题
*
* @return Jackson2ObjectMapperBuilderCustomizer 注入的对象
*/
@Bean
public Jackson2ObjectMapperBuilderCustomizer jackson2ObjectMapperBuilderCustomizer() {
return jacksonObjectMapperBuilder -> jacksonObjectMapperBuilder
.serializerByType(Long.class, ToStringSerializer.instance)
.serializerByType(Long.TYPE, ToStringSerializer.instance);
}
}