feign.codec.EncodeException: class java.util.ArrayList is not a type supported by this encoder

原創 Murphy_fly 2020-04-29 15:49

問題背景

在springcloud 盛行的今天 , 我們無可避免的要面對服務間的調用 . 最常用的就是feign client 這種方式進行服務之間調用了.

在疫情緊張的某一天. 我需要使用feign client開發一個接口, 這個接口是post 請求, 參數是一個VO 對象. 於是乎我定義接口如下. 

//發生異常的接口
@FeignClient(name = DeviceServiceName.SERVICE_NAME, fallbackFactory = DemoClient.DemoClientFallback.class)
public interface DemoService {   
    @PostMapping(value = "/adm/device/post/demo",consumes = MediaType.APPLICATION_JSON_VALUE)
    public R<Device> postDevice(@RequestBody  Device device) ;
}

當我定義完後,屁顛屁顛就開始調式了. 不開心的事情終究還是發生了. 嗝屁了.尷尬.報了下面的錯誤

錯誤

2020-04-27 14:19:41,086 ERROR [http-nio-8008-exec-2] org.skywayframework.common.handler.GlobalExceptionHandler : [SEI-ERROR] System exception, unknown error! message is : class java.util.ArrayList is not a type supported by this encoder. !
feign.codec.EncodeException: class java.util.ArrayList is not a type supported by this encoder.
	at feign.codec.Encoder$Default.encode(Encoder.java:94) ~[feign-core-10.1.0.jar:na]
	at feign.form.FormEncoder.encode(FormEncoder.java:90) ~[feign-form-3.8.0.jar:na]
	at feign.form.spring.SpringFormEncoder.encode(SpringFormEncoder.java:64) ~[feign-form-spring-3.5.0.jar:na]
	at feign.ReflectiveFeign$BuildEncodedTemplateFromArgs.resolve(ReflectiveFeign.java:372) ~[feign-core-10.1.0.jar:na]
	at feign.ReflectiveFeign$BuildTemplateByResolvingArgs.create(ReflectiveFeign.java:224) ~[feign-core-10.1.0.jar:na]
	at feign.SynchronousMethodHandler.invoke(SynchronousMethodHandler.java:74) ~[feign-core-10.1.0.jar:na]
	at feign.ReflectiveFeign$FeignInvocationHandler.invoke(ReflectiveFeign.java:103) ~[feign-core-10.1.0.jar:na]
	at com.sun.proxy.$Proxy183.postListDevice(Unknown Source) ~[na:na]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_181]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_181]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_181]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_181]
	at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:343) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:198) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.aspectj.MethodInvocationProceedingJoinPoint.proceed(MethodInvocationProceedingJoinPoint.java:100) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.skywayframework.common.config.RequestAspect.doAround(RequestAspect.java:128) ~[classes/:na]
	at org.skywayframework.common.config.RequestAspect.postMappingDoAround(RequestAspect.java:68) ~[classes/:na]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_181]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_181]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_181]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_181]
	at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethodWithGivenArgs(AbstractAspectJAdvice.java:644) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethod(AbstractAspectJAdvice.java:633) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.aspectj.AspectJAroundAdvice.invoke(AspectJAroundAdvice.java:70) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:175) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:93) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at com.sun.proxy.$Proxy184.postListDevice(Unknown Source) ~[na:na]
	at org.skywayframework.system.controller.AdminDemoController.postListDemo(AdminDemoController.java:50) ~[classes/:na]
	at org.skywayframework.system.controller.AdminDemoController$$FastClassBySpringCGLIB$$10b091d3.invoke(<generated>) ~[classes/:na]
	at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218) ~[spring-core-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:749) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.aspectj.MethodInvocationProceedingJoinPoint.proceed(MethodInvocationProceedingJoinPoint.java:100) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.skywayframework.common.config.RequestAspect.doAround(RequestAspect.java:128) ~[classes/:na]
	at org.skywayframework.common.config.RequestAspect.postMappingDoAround(RequestAspect.java:68) ~[classes/:na]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_181]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_181]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_181]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_181]
	at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethodWithGivenArgs(AbstractAspectJAdvice.java:644) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethod(AbstractAspectJAdvice.java:633) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.aspectj.AspectJAroundAdvice.invoke(AspectJAroundAdvice.java:70) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:175) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:93) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:688) ~[spring-aop-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.skywayframework.system.controller.AdminDemoController$$EnhancerBySpringCGLIB$$c48246a5.postListDemo(<generated>) ~[classes/:na]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_181]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_181]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_181]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_181]
	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:189) ~[spring-web-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) ~[spring-web-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102) ~[spring-webmvc-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895) ~[spring-webmvc-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:800) ~[spring-webmvc-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1038) ~[spring-webmvc-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:942) ~[spring-webmvc-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1005) [spring-webmvc-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:908) [spring-webmvc-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:660) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:882) [spring-webmvc-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) [tomcat-embed-websocket-9.0.14.jar:9.0.14]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at com.github.xiaoymin.knife4j.spring.filter.ProductionSecurityFilter.doFilter(ProductionSecurityFilter.java:53) [knife4j-spring-2.0.2.jar:na]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at com.github.xiaoymin.knife4j.spring.filter.SecurityBasicAuthFilter.doFilter(SecurityBasicAuthFilter.java:90) [knife4j-spring-2.0.2.jar:na]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at com.alibaba.druid.support.http.WebStatFilter.doFilter(WebStatFilter.java:123) [druid-1.1.10.jar:1.1.10]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.springframework.cloud.sleuth.instrument.web.ExceptionLoggingFilter.doFilter(ExceptionLoggingFilter.java:50) [spring-cloud-sleuth-core-2.1.0.RELEASE.jar:2.1.0.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at brave.servlet.TracingFilter.doFilter(TracingFilter.java:86) [brave-instrumentation-servlet-5.6.1.jar:na]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200) [spring-web-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.1.4.RELEASE.jar:5.1.4.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:834) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1417) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_181]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_181]
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.14.jar:9.0.14]
	at java.lang.Thread.run(Thread.java:748) [na:1.8.0_181]
2020-04-27 14:19:41,121 INFO  [http-nio-8008-exec-2] org.skywayframework.common.interceptor.RequestParamInterceptor : [SEI-DEBUG] POST :  the url is /demo/device/post2 !

 

我使用的技術棧如下

Springboot     2.1.2.RELEASE

SpringCloud    Greenwich.RELEASE

OpenFeign      2.1.0RELEASE

錯誤原因分析

老規矩,首先看看feign 中默認的Jackson Encoder

package feign.jackson;

public class JacksonEncoder implements Encoder {
    private final ObjectMapper mapper;

    public JacksonEncoder() {
        this((Iterable)Collections.emptyList());
    }

    public JacksonEncoder(Iterable<Module> modules) {
        this((new ObjectMapper()).setSerializationInclusion(Include.NON_NULL).configure(SerializationFeature.INDENT_OUTPUT, true).registerModules(modules));
    }

    public JacksonEncoder(ObjectMapper mapper) {
        this.mapper = mapper;
    }

    public void encode(Object object, Type bodyType, RequestTemplate template) {
        try {
            JavaType javaType = this.mapper.getTypeFactory().constructType(bodyType);
            template.body(this.mapper.writerFor(javaType).writeValueAsString(object));
        } catch (JsonProcessingException var5) {
            throw new EncodeException(var5.getMessage(), var5);
        }
    }

核心的encoder方法就是在服務調用的時候進行解碼. 自定義類型它無法識別. 它並不能識別我們自定義的Device 類!!!

通過stack overflow 查一下相關問題 , 鏈接 How to POST form-url-encoded data with Spring Cloud Feign

分析出原因需要自定義解碼器.  好了. 問題找到了 ,開始行動吧

解決辦法

1.client 接口定義需要指定一個configuration  ,告訴client 使用哪一個encoder 

2.聲明一個feignFormEncoder, 並聲明爲spring中的一個Bean

 源代碼如下:

@FeignClient(name = DeviceServiceName.SERVICE_NAME, fallbackFactory = DemoClient.DemoClientFallback.class,configuration = DemoClient.Configuration.class)
public interface DemoService {

    @PostMapping(value = "/adm/device/post/demo",consumes = MediaType.APPLICATION_JSON_VALUE)
    public R<Device> postDevice(@RequestBody  Device device) ;

    class Configuration {

        @Bean
        Encoder feignFormEncoder(ObjectFactory<HttpMessageConverters> converters) {
            return new SpringFormEncoder(new SpringEncoder(converters));
        }
    }
    
}

驗證問題是否解決

PS: 再次嘗試發送同樣的請求, 服務之間調用沒有再報異常 . 得到如下結果

{
	"code": 0,
	"message": "success",
	"signature": "61111c7a7fbb407b9eb00bdb559e1774",
	"requestId": "61111c7a7fbb407b9eb00bdb559e1774",
	"timestamp": 1587969336934,
	"body": {
		"count": 2,
		"size": 0,
		"current": 0,
		"data": [{
			"devId": null,
			"model": "model",
			"sn": null,
			"ethMac": null,
			"wifiMac": null,
			"cpu": "cpu-demo",
			"internalStorage": null,
			"ram": null,
			"vcId": null
		}, {
			"devId": null,
			"model": "mode2",
			"sn": null,
			"ethMac": null,
			"wifiMac": null,
			"cpu": "cpu-demo2",
			"internalStorage": null,
			"ram": null,
			"vcId": null
		}]
	}
} {
	"tenantCode": "SEI110D000000000094",
	"apkInfoList": [{
		"apkPackage": "",
		"apkVersion": ""
	}]
}

問題得到解決!!!  你就可以愉快地使用Feign 傳遞自定義對象, 或者List<T> 這種類型的參數啦.美滋滋!!!

當然,這個configuration 可以聲明在一個公共的地方, 所有的client 都可以共享啦 .滴 ,打卡下班

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轉載自tuoluzhe8521 導讀：通過簡化複雜的任務依賴關係， DolphinScheduler爲數據工程師提供了強大的工作流程管理和調度能力。在3.2.0版本中，DolphinScheduler帶來了一系列新功能和改進，使其在生產環

原創 2024-05-15 21:22:54

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微服務Gateway 微服務網關部署在前端Nginx網關和後端微服務之間，Nginx一般充當流量網關，而微服務網關屬於一種業務型 網關，微服務網關層爲後端的微服務羣組提供統一的接入地址，其核心功能是統一做服務路由，在路由基礎上還 可以實現一

原創 2024-05-15 11:50:15

JDBC連接openGauss6.0和PostgreSQL16.2性能對比

本文分享自華爲雲社區《JDBC連接openGauss6.0和PostgreSQL16.2性能對比》，作者： Gauss松鼠會小助手。 PostgreSQL vs openGauss 01 前置準備 安裝JDK： 詳細安裝步驟請問度娘，輸

原創 2024-05-14 11:00:08

爲什麼阿里不建議用excutors創建線程池

1 前言：         大家都知道，阿里規範中有一條是不允許用excutors去創建線程池，而是採用ThreadPoolExecutor的原生方式去創建。很早就聽過所過這種說法，但是一直都沒去搞清楚是爲什麼，今天就查閱資料去了解了這

原創 2024-05-14 02:07:06

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1)編碼     消息長度(short int-->2個字節) + 消息編號(short int--》2個字節) + 消息體 2)Protobuf協議文檔     (1)syntax="proto3";     (2)命名格式       

osc_hwc3munb 2024-05-14 02:04:28

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很早之前寫過一篇《Android內存管理機制詳解》點擊量已7萬+，現把Google官方文檔整理輸出一下，供各位參考。 一、內存管理概覽 Android 運行時 (ART) 和 Dalvik 虛擬機使用分頁和內存映射來管理內存。這意味着應用

osc_51airx3z 2024-05-14 00:37:42

OSS_PIPE：Rust編寫的大規模文件遷移工具| 京東雲技術團隊

文盤rust 好久沒有更新了。這段時間筆者用rust寫了個小東西，跟各位分享一下 背景 隨着業務的發展，文件數量和文件大小會急劇增加，文件遷移的數量和難度不斷攀升。oss_pipe 是rust編寫的文件遷移工具，旨在支撐大規模的文件遷移場

原創 2024-05-13 23:59:27

面試官：說說你對序列化的理解

本文主要內容 背景 在Java語言中，程序運行的時候，會產生很多對象，而對象信息也只是在程序運行的時候纔在內存中保持其狀態，一旦程序停止，內存釋放，對象也就不存在了。 怎麼能讓對象永久的保存下來呢？--------對象序列化 。 何

osc_61miaq6u 2024-05-13 22:58:28

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綱要 String StringBuffer 基礎類型對應的8個包裝類 日期相關類 數字相關類 Random Enum 1. 理解String類的存儲原理 String類是不可變類，也就是說String對象聲明後，將不可修改。 S

osc_6mbnx553 2024-05-13 22:07:29