内容简述目的解决servlet request InputStream body只能读取一次的问题设置请求级别的线程变量 ThreadLocal注意Fitler 执行循序以免在wrapper 初始化前body已经消费Request wrapperwrapper重写和 body 读取相关的 3 个核心方法- getInputStream()- getReader()- getContentLength()javaimport java.io.*; public class RepeatableHttpServletRequestWrapper extends HttpServletRequestWrapper { /** 缓存请求体字节数组 */ private byte[] body; /** * Constructs a request object wrapping the given request. * * param request The request to wrap * throws IllegalArgumentException if the request is null */ public RepeatableHttpServletRequestWrapper(HttpServletRequest request) throws IOException { super(request); this.body toByteArray(request.getInputStream()); } /** * 将输入流读取为字节数组 * * param input 输入流 * return 字节数组 * throws IOException 读取失败时抛出 */ private static byte[] toByteArray(InputStream input) throws IOException { ByteArrayOutputStream buffer new ByteArrayOutputStream(); byte[] data new byte[4096]; int n; while ((n input.read(data, 0, data.length)) ! -1) { buffer.write(data, 0, n); } return buffer.toByteArray(); } Override public ServletInputStream getInputStream() { ByteArrayInputStream input new ByteArrayInputStream(body); return new ServletInputStream() { Override public boolean isFinished() { return false; } Override public boolean isReady() { return false; } Override public void setReadListener(ReadListener listener) { } Override public int read(){ return input.read(); } }; } Override public BufferedReader getReader(){ return new BufferedReader(new InputStreamReader(getInputStream())); } Override public int getContentLength() { return body.length; } /** * 获取缓存的请求体字节数组 * * return 请求体字节数组 */ public byte[] getBody() { return body; } }filterimportjakarta.servlet.FilterChain;importjakarta.servlet.ServletException;importjakarta.servlet.http.HttpServletRequest;importjakarta.servlet.http.HttpServletResponse;importorg.springframework.web.filter.OncePerRequestFilter;importjava.io.IOException;publicclassRepeatableReadFilterextendsOncePerRequestFilter{OverrideprotectedvoiddoFilterInternal(HttpServletRequestrequest,HttpServletResponseresponse,FilterChainfilterChain)throwsServletException,IOException{if(request.getContentType()!null){RepeatableHttpServletRequestWrapperwrapperRequestnewRepeatableHttpServletRequestWrapper(request);filterChain.doFilter(wrapperRequest,response);}else{filterChain.doFilter(request,response);}}}Request context holder自定义Request context Objectimportlombok.*;GetterSetterNoArgsConstructorAllArgsConstructorToStringpublicclassRequestContextHolderObjectT{privateStringUUID;privateTt;}实现RequestContextHolderpublicclassRequestContextHolder{privatestaticfinalInheritableThreadLocalObjectthreadLocalnewInheritableThreadLocal();publicstaticTvoidset(RequestContextHolderObjectTcommonHeader){threadLocal.set(commonHeader);}SuppressWarnings(unchecked)publicstaticTRequestContextHolderObjectTget(){return(RequestContextHolderObjectT)threadLocal.get();}publicstaticvoidremove(){threadLocal.remove();}publicstaticStringgetUUID(){RequestContextHolderObjectObjectobjectRequestContextHolderObjectget();if(objectRequestContextHolderObjectnull){returnnull;}returnobjectRequestContextHolderObject.getUUID();}}Filter 实现publicclassCustomerRequestContextFilterextendsOncePerRequestFilter{OverrideprotectedvoiddoFilterInternal(HttpServletRequestrequest,HttpServletResponseresponse,FilterChainfilterChain)throwsServletException,IOException{// 继承 MDC 中有 traceId没有生成新的try{StringtraceIdMDC.get(traceId);StringuuidStringUtil.isEmptyString(traceId)?UUID.randomUUID().toString():traceId;RequestContextHolder.set(newRequestContextHolderObjectObject(uuid,test));filterChain.doFilter(request,response);}finally{RequestContextHolder.remove();}}}子线程或者线程池传递修改RequestContextHolder 使用TTLTransmittableThreadLocal (TTL)自定义线程池添加传递Decorator 实现importcom.ft.mall.common.web.requestholder.RequestContextHolder;importcom.ft.mall.common.web.requestholder.RequestContextHolderObject;importorg.slf4j.MDC;importorg.springframework.context.annotation.Bean;importorg.springframework.core.task.TaskDecorator;importorg.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;importjava.util.Map;importjava.util.concurrent.Executor;publicclassSimpleExecutor{Bean(asyncExecutor)publicExecutorasyncExecutor(){ThreadPoolTaskExecutorexecutornewThreadPoolTaskExecutor();executor.setCorePoolSize(10);executor.setMaxPoolSize(20);executor.setQueueCapacity(100);executor.setThreadNamePrefix(async-);// 配置MDC上下文传递装饰器executor.setTaskDecorator(newMdcTaskDecorator());executor.initialize();returnexecutor;}/** * MDC上下文传递装饰器 */staticclassMdcTaskDecoratorimplementsTaskDecorator{OverridepublicRunnabledecorate(Runnablerunnable){// 父线程拷贝MDC上下文MapString,StringcontextMapMDC.getCopyOfContextMap();RequestContextHolderObjectObjectobjectRequestContextHolderObjectRequestContextHolder.get();return()-{try{// 子线程设置MDCif(contextMap!null){MDC.setContextMap(contextMap);RequestContextHolder.set(objectRequestContextHolderObject);}runnable.run();}finally{MDC.clear();RequestContextHolder.remove();}};}}}filter 注册importcom.ft.mall.common.web.filter.RepeatableReadFilter;importjakarta.servlet.Filter;importorg.springframework.boot.web.servlet.FilterRegistrationBean;importorg.springframework.context.annotation.Bean;importorg.springframework.context.annotation.Configuration;importorg.springframework.core.Ordered;importorg.springframework.web.servlet.config.annotation.WebMvcConfigurer;ConfigurationpublicclassWebConfigimplementsWebMvcConfigurer{/** * 注册可重复读请求体过滤器 * * p拦截所有路径优先级最高确保在 Spring 拦截器和其他 Filter 之前包装请求。 * * return Filter 注册 Bean */BeanpublicFilterRegistrationBeanFilterrepeatableReadFilter(){FilterRegistrationBeanFilterregistrationnewFilterRegistrationBean();registration.setFilter(newRepeatableReadFilter());registration.addUrlPatterns(/*);registration.setOrder(Ordered.HIGHEST_PRECEDENCE);registration.setName(repeatbleFilter);returnregistration;}BeanpublicFilterRegistrationBeanFilterrequestContextHolderFilter(){FilterRegistrationBeanFilterregistrationnewFilterRegistrationBean();registration.setFilter(newCustomerRequestContextFilter());registration.addUrlPatterns(/*);registration.setOrder(Ordered.HIGHEST_PRECEDENCE2);registration.setName(requestContextHolderFilter);returnregistration;}}