1，問題場景

???????? 后端返回的Long類型的數據，超10000000000000000，前端處理的時候，數據被截斷了。比如tchId: 11073477511443988481， 前端根據tchId獲取下一環節信息的時候，傳的tchId變成了11073477511443988400，導致報錯。

? ? 主要是因為JavaScript中的Number類型無法精確表示超過其安全整數范圍（即-9007199254740991（-2^53 + 1）到9007199254740991（2^53 - 1））的整數值。因此，當后端Java的Long類型數據超過這個范圍時，前端JavaScript在解析這些數據時就會丟失精度。

? ? ? ? 因此當Long類型超過的時候，需要把Long類型，轉成字符串返回給前端。

2，處理：

1，處理方法1：字段加注解

????????可以使用Jackson庫的@JsonFormat注解來將Long類型字段序列化為字符串類型。這樣，在數據傳輸到前端時，就會以字符串的形式進行傳輸，從而避免了精度丟失的問題，如代碼字段返回轉換成字符串。

import com.fasterxml.jackson.annotation.JsonFormat;public class Tache {@JsonFormat(shape = JsonFormat.Shape.STRING)private Long tchld;
}

這種就只適合指定的字段，不通用。如果要設置未全局要怎么做？

2，處理方法2：全局處理

????????為了更加便捷地解決這個問題，使用全局配置，將所有Long類型的數據都轉換為字符串類型。通過配置Jackson的ObjectMapper來實現

引用：

implementation 'com.fasterxml.jackson.core:jackson-core:2.13.5'

判斷處理：

public class StringSerializer extends StdSerializer<Object> {private static Logger logger = LoggerFactory.getLogger(StringSerializer.class);public final static StringSerializer instance = new StringSerializer();public StringSerializer() {super(Object.class);}public StringSerializer(Class<?> handledType) {super(handledType, false);}@Overridepublic void serialize(Object value, JsonGenerator gen, SerializerProvider provider) throws IOException {if (value != null && value instanceof Long) {if (((Long) value).longValue() >= 10000000000000000L) {gen.writeString(value.toString());} else {gen.writeNumber((Long) value);}}}
}

配置：

@Configuration
@EnableWebMvc
public class WebMvcConfiguration implements WebMvcConfigurer {@Overridepublic void addResourceHandlers(ResourceHandlerRegistry registry) {registry.addResourceHandler("/**").addResourceLocations("classpath:/static/");registry.addResourceHandler("/**").addResourceLocations("classpath:/META-INF/resources/");registry.addResourceHandler("/webjars/**").addResourceLocations("classpath:/META-INF/resources/webjars/");}@Beanpublic ObjectMapper jacksonObjectMapperCustomization() {TimeZone timeZone = TimeZone.getTimeZone("Asia/Shanghai");Jackson2ObjectMapperBuilder builder = new Jackson2ObjectMapperBuilder().timeZone(timeZone);return builder.build();}@Overridepublic void configureMessageConverters(List<HttpMessageConverter<?>> converters) {converters.removeIf(c -> c instanceof MappingJackson2HttpMessageConverter);MappingJackson2HttpMessageConverter jackson2HttpMessageConverter = new MappingJackson2HttpMessageConverter(jacksonObjectMapperCustomization());ObjectMapper objectMapper = new ObjectMapper();SimpleModule simpleModule = new SimpleModule();simpleModule.addSerializer(Long.class, StringSerializer.instance);simpleModule.addSerializer(Long.TYPE, StringSerializer.instance);objectMapper.registerModule(simpleModule);objectMapper.setTimeZone(TimeZone.getTimeZone("GMT+8"));objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);jackson2HttpMessageConverter.setObjectMapper(objectMapper);converters.add(jackson2HttpMessageConverter);converters.add(new ByteArrayHttpMessageConverter());converters.add(new FormHttpMessageConverter());converters.add(new StringHttpMessageConverter(Charset.forName("UTF-8")));}@Beanpublic LocaleChangeInterceptor localeChangeInterceptor() {LocaleChangeInterceptor localeChangeInterceptor = new LocaleChangeInterceptor();localeChangeInterceptor.setParamName("LOCALE");return localeChangeInterceptor;}@Overridepublic void addInterceptors(InterceptorRegistry registry) {registry.addInterceptor(localeChangeInterceptor());}@Beanprotected RequestMappingHandlerMapping createRequestMappingHandlerMapping() {return new RequestMappingHandlerMapping() {@Overrideprotected boolean isHandler(Class<?> beanType) {return (AnnotatedElementUtils.hasAnnotation(beanType, Controller.class)|| (AnnotatedElementUtils.hasAnnotation(beanType, RequestMapping.class)&& !AnnotatedElementUtils.hasAnnotation(beanType, FeignClient.class)));}};}@Beanpublic WebMvcEndpointHandlerMapping webEndpointServletHandlerMapping(WebEndpointsSupplier webEndpointsSupplier, ServletEndpointsSupplier servletEndpointsSupplier, ControllerEndpointsSupplier controllerEndpointsSupplier, EndpointMediaTypes endpointMediaTypes, CorsEndpointProperties corsProperties, WebEndpointProperties webEndpointProperties, Environment environment) {List<ExposableEndpoint<?>> allEndpoints = new ArrayList<>();Collection<ExposableWebEndpoint> webEndpoints = webEndpointsSupplier.getEndpoints();allEndpoints.addAll(webEndpoints);allEndpoints.addAll(servletEndpointsSupplier.getEndpoints());allEndpoints.addAll(controllerEndpointsSupplier.getEndpoints());String basePath = webEndpointProperties.getBasePath();EndpointMapping endpointMapping = new EndpointMapping(basePath);boolean shouldRegisterLinksMapping = this.shouldRegisterLinksMapping(webEndpointProperties, environment, basePath);return new WebMvcEndpointHandlerMapping(endpointMapping, webEndpoints, endpointMediaTypes, corsProperties.toCorsConfiguration(), new EndpointLinksResolver(allEndpoints, basePath), shouldRegisterLinksMapping, null);}private boolean shouldRegisterLinksMapping(WebEndpointProperties webEndpointProperties, Environment environment, String basePath) {return webEndpointProperties.getDiscovery().isEnabled() && (StringUtils.hasText(basePath) || ManagementPortType.get(environment).equals(ManagementPortType.DIFFERENT));}
}

處理的代碼：

simpleModule.addSerializer(Long.class, StringSerializer.instance);
simpleModule.addSerializer(Long.TYPE, StringSerializer.instance);

總結：

? ? ? ? 如果是只有某些指定數據進行轉換，就直接加注解的方式，要全局的話，就用全局的配置去處理。