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2022-11-21
JAVA8-CompletableFuture常用API:thenApply、handle、thenRun、thenAccept、thenCompose、thenCombine、thenAcceptBoth
JAVA8-CompletableFuture常用API:thenApply、handle、thenRun、thenAccept、thenCompose、thenCombine、thenAcceptBoth1、thenApplypackage com.example.study.java8.completableFutures.api; import java.util.Optional; import java.util.concurrent.CompletableFuture; /** * CompletableFuture常用API: thenApply、handle */ public class CompletableFutureAtion1 { public static void main(String[] args) throws InterruptedException { //API-- 1、thenApply //模拟其它 异步 逻辑操作然后返回结果1 CompletableFuture.supplyAsync(() -> 1) .thenApply(i -> Integer.sum(i, 10)) //thenApply 将结果加10 .whenComplete((v, t) -> Optional.ofNullable(v).ifPresent(System.out::println)); //同步执行打印结果 // .whenCompleteAsync() //异步操作,可以将结果在进行其它逻辑异步操作 //whenComplete VS whenCompleteAsync //为了防止主线程结束后,守护线程被关闭,模拟修改10000毫秒 Thread.sleep(10000); } } 输出结果:11对比whenComplete VS whenCompleteAsync:whenCompleteAsync异步操作,可以将结果在进行其它逻辑异步操作。2、handlepackage com.example.study.java8.completableFutures.api; import java.util.Optional; import java.util.concurrent.CompletableFuture; /** * CompletableFuture常用API: thenApply、handle */ public class CompletableFutureAtion1 { public static void main(String[] args) throws InterruptedException { //API- 2、handle CompletableFuture.supplyAsync(() -> 1) .handle((v, t) -> Integer.sum(v, 10)) .whenComplete((v, t) -> Optional.ofNullable(v).ifPresent(System.out::println)); // thenApply VS handle :handle只是多了一个对堆内存的考虑。 //为了防止主线程结束后,守护线程被关闭,模拟修改10000毫秒 Thread.sleep(10000); } } 输出结果:11对比thenApply VS handle :handle只是多了一个对堆内存的考虑。3、thenRunpackage com.example.study.java8.completableFutures.api; import java.util.Optional; import java.util.concurrent.CompletableFuture; /** * CompletableFuture常用API: thenApply、handle */ public class CompletableFutureAtion1 { public static void main(String[] args) throws InterruptedException { //API-3、thenRun:所有结果执行完后,执行其它操作 CompletableFuture.supplyAsync(() -> 1) .handle((v, t) -> Integer.sum(v, 10)) .whenComplete((v, t) -> Optional.ofNullable(v).ifPresent(System.out::println)) .thenRun(System.out::println); //这里没有入参,只会打印一个换行 // .thenRunAsync() 如果做成异步的就用这个方法 //为了防止主线程结束后,守护线程被关闭,模拟修改10000毫秒 Thread.sleep(10000); } }输出结果:11 //这里打印了一个换行对比thenRun VS thenRunAsync :thenRunAsync 做成异步的就用这个方法。4、thenAcceptpackage com.example.study.java8.completableFutures.api; import java.util.Optional; import java.util.concurrent.CompletableFuture; /** * CompletableFuture常用API: thenApply、handle */ public class CompletableFutureAtion1 { public static void main(String[] args) throws InterruptedException { //API-4、thenAccept:不会有任何返回值,只是对结果进行消费 CompletableFuture.supplyAsync(() -> 1) .thenAccept(System.out::println); //为了防止主线程结束后,守护线程被关闭,模拟修改10000毫秒 Thread.sleep(10000); } } 输出结果:15、thenComposepackage com.example.study.java8.completableFutures.api; import java.util.Optional; import java.util.concurrent.CompletableFuture; /** * CompletableFuture常用API: thenApply、handle */ public class CompletableFutureAtion1 { public static void main(String[] args) throws InterruptedException { //API-5、thenCompose:将异步产生的结果,再交(组合)给另一个ComletableFuture进行处理,是有返回值的。 CompletableFuture.supplyAsync(() -> 1) .thenCompose(i -> CompletableFuture.supplyAsync(() -> 10 * i)) //将1再组合成另一个CompletableFuture处理 .thenAccept(System.out::println); //然后消费,直接输出结果 //为了防止主线程结束后,守护线程被关闭,模拟修改10000毫秒 Thread.sleep(10000); } }输出结果:106、thenCombinepackage com.example.study.java8.completableFutures.api; import java.util.Optional; import java.util.concurrent.CompletableFuture; /** * CompletableFuture常用API: thenApply、handle */ public class CompletableFutureAtion1 { public static void main(String[] args) throws InterruptedException { //API-6、thenCombine:将异步产生的结果,与另一个CompletableFuture结果,作为参数进行处理,有返回值。 CompletableFuture.supplyAsync(() -> 1) .thenCombine(CompletableFuture.supplyAsync(()->0.2),(v1,v2)->v1+v2) .thenAccept(System.out::println); //为了防止主线程结束后,守护线程被关闭,模拟修改10000毫秒 Thread.sleep(10000); } }输出结果:1.27、thenAcceptBothpackage com.example.study.java8.completableFutures.api; import java.util.Optional; import java.util.concurrent.CompletableFuture; /** * CompletableFuture常用API: thenApply、handle */ public class CompletableFutureAtion1 { public static void main(String[] args) throws InterruptedException { //API-7、thenAcceptBoth:将异步产生的结果,与另一个CompletableFuture结果,作为参数进行处理,没有返回值,直接用于消费。 CompletableFuture.supplyAsync(() -> 1) .thenAcceptBoth(CompletableFuture.supplyAsync(()->0.5), (v1,v2)->{ System.out.println(v1); System.out.println(v2); }); // thenCombine VS thenAcceptBoth:2个方法类似,有个有返回值,有个没有返回值。 //为了防止主线程结束后,守护线程被关闭,模拟修改10000毫秒 Thread.sleep(10000); } } 输出结果:1 0.5CompletableFuture常用API使用:1、thenApply2、handle3、thenRun4、thenAccept5、thenCompose6、thenCombine7、thenAcceptBoth
2022年11月21日
136 阅读
0 评论
4 点赞
2022-11-21
JAVA8-CompletableFuture基本用法
JAVA8-CompletableFuture基本用法针对<实现一个异步基于事件回调的Future程序> 用CompletableFuture进行改进。代码示例:package com.example.study.java8.completableFutures; import java.util.Optional; import java.util.Random; import java.util.concurrent.CompletableFuture; import java.util.concurrent.ExecutionException; /** * CompletableFuture 基本用法 */ public class CompletableFutureInAction1 { private final static Random RANDOM = new Random(System.currentTimeMillis()); public static void main(String[] args) throws ExecutionException, InterruptedException { //实际开发中,一般不直接new,而是使用工厂创建 // CompletableFuture<Void> voidCompletableFuture = CompletableFuture.runAsync(); CompletableFuture<Double> completableFuture = new CompletableFuture<>(); new Thread(()->{ double value = get(); completableFuture.complete(value); }).start(); //不会阻塞程序执行 System.out.println("===========no====block====.."); //1、后面获取程序执行结果 // Optional.ofNullable(completableFuture.get()).ifPresent(System.out::println); //2、执行完后,通过回调自动返回结果 completableFuture.whenComplete((v,t)->{ Optional.ofNullable(v).ifPresent(System.out::println); Optional.ofNullable(t).ifPresent(x->x.printStackTrace()); }); } private static double get(){ try { Thread.sleep(RANDOM.nextInt(10000)); } catch (InterruptedException e) { e.printStackTrace(); } return RANDOM.nextDouble(); } }输出结果:===========no====block====.. 0.5192854493861505
2022年11月21日
140 阅读
0 评论
2 点赞
2022-03-15
SpringBoot整合定时任务和异步任务
SpringBoot整合定时任务和异步任务一、定时任务SpringBoot整合quartz-scheduler,执行定时任务。1、开启定时任务@EnableScheduling2、开启一个定时任务@Scheduled3、编写cron表达式cron表达式格式请参考官方文档4、实例package com.yanxizhu.ifamily.booking.controller.scheduler; import lombok.extern.slf4j.Slf4j; import org.springframework.scheduling.annotation.EnableScheduling; import org.springframework.scheduling.annotation.Scheduled; import org.springframework.stereotype.Component; /** * SpringBoot整合Scheduling定时任务 * @author: <a href="mailto:vip@foxmail.com">清风</a> * @date: 2022/3/15 20:26 * @version: 1.0 */ @Slf4j @Component @EnableScheduling public class MyScheduler { /** * cron表达式 */ @Scheduled(cron = "1/3 1/1 * * * ? ") public void sayHell(){ log.info("Hello"); } }5、定时任务总结1、@EnableScheduling 开启一个定时任务2、@Scheduled 开启一个定时任务3、编写定时规则,也就是cron表达式。6、注意事项spring中6位组成,不允许第7位的年。在周几的位置,1-7代表周一到周日,MON-SUN定时任务不应该阻塞,默认时阻塞的,应该以异步任务执行。7、解决方案解决定时任务阻塞问题:使用异步+定时任务二、异步任务执行几种方式1、异步方式提交线程池可以让业务运行以异步的方式,自己提交到线程池(CompletableFuture异步编排)。@Slf4j @Component @EnableScheduling public class MyScheduler { public static ExecutorService executorService = Executors.newFixedThreadPool(10); /** * cron表达式 */ @Scheduled(cron = "1/3 1/1 * * * ? ") public void sayHell(){ CompletableFuture.runAsync(()->{ //调用server业务方法 }, executorService); } }2、定时任务线程池支持定时任务线程池(定时任务线程池)。Scheduling自动配置类,默认只有1个线程。// // Source code recreated from a .class file by IntelliJ IDEA // (powered by FernFlower decompiler) // package org.springframework.boot.autoconfigure.task; import java.util.concurrent.ScheduledExecutorService; import org.springframework.beans.factory.ObjectProvider; import org.springframework.boot.LazyInitializationExcludeFilter; import org.springframework.boot.autoconfigure.AutoConfigureAfter; import org.springframework.boot.autoconfigure.condition.ConditionalOnBean; import org.springframework.boot.autoconfigure.condition.ConditionalOnClass; import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean; import org.springframework.boot.autoconfigure.task.TaskSchedulingProperties.Shutdown; import org.springframework.boot.context.properties.EnableConfigurationProperties; import org.springframework.boot.task.TaskSchedulerBuilder; import org.springframework.boot.task.TaskSchedulerCustomizer; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.scheduling.TaskScheduler; import org.springframework.scheduling.annotation.SchedulingConfigurer; import org.springframework.scheduling.concurrent.ThreadPoolTaskScheduler; @ConditionalOnClass({ThreadPoolTaskScheduler.class}) @Configuration( proxyBeanMethods = false ) @EnableConfigurationProperties({TaskSchedulingProperties.class}) @AutoConfigureAfter({TaskExecutionAutoConfiguration.class}) public class TaskSchedulingAutoConfiguration { public TaskSchedulingAutoConfiguration() { } @Bean @ConditionalOnBean( name = {"org.springframework.context.annotation.internalScheduledAnnotationProcessor"} ) @ConditionalOnMissingBean({SchedulingConfigurer.class, TaskScheduler.class, ScheduledExecutorService.class}) public ThreadPoolTaskScheduler taskScheduler(TaskSchedulerBuilder builder) { return builder.build(); } @Bean public static LazyInitializationExcludeFilter scheduledBeanLazyInitializationExcludeFilter() { return new ScheduledBeanLazyInitializationExcludeFilter(); } @Bean @ConditionalOnMissingBean public TaskSchedulerBuilder taskSchedulerBuilder(TaskSchedulingProperties properties, ObjectProvider<TaskSchedulerCustomizer> taskSchedulerCustomizers) { TaskSchedulerBuilder builder = new TaskSchedulerBuilder(); builder = builder.poolSize(properties.getPool().getSize()); Shutdown shutdown = properties.getShutdown(); builder = builder.awaitTermination(shutdown.isAwaitTermination()); builder = builder.awaitTerminationPeriod(shutdown.getAwaitTerminationPeriod()); builder = builder.threadNamePrefix(properties.getThreadNamePrefix()); builder = builder.customizers(taskSchedulerCustomizers); return builder; } }默认只有一个线程package org.springframework.boot.autoconfigure.task; import java.time.Duration; import org.springframework.boot.context.properties.ConfigurationProperties; @ConfigurationProperties("spring.task.scheduling") public class TaskSchedulingProperties { private final TaskSchedulingProperties.Pool pool = new TaskSchedulingProperties.Pool(); private final TaskSchedulingProperties.Shutdown shutdown = new TaskSchedulingProperties.Shutdown(); private String threadNamePrefix = "scheduling-"; public TaskSchedulingProperties() { } public TaskSchedulingProperties.Pool getPool() { return this.pool; } public TaskSchedulingProperties.Shutdown getShutdown() { return this.shutdown; } public String getThreadNamePrefix() { return this.threadNamePrefix; } public void setThreadNamePrefix(String threadNamePrefix) { this.threadNamePrefix = threadNamePrefix; } public static class Shutdown { private boolean awaitTermination; private Duration awaitTerminationPeriod; public Shutdown() { } public boolean isAwaitTermination() { return this.awaitTermination; } public void setAwaitTermination(boolean awaitTermination) { this.awaitTermination = awaitTermination; } public Duration getAwaitTerminationPeriod() { return this.awaitTerminationPeriod; } public void setAwaitTerminationPeriod(Duration awaitTerminationPeriod) { this.awaitTerminationPeriod = awaitTerminationPeriod; } } public static class Pool { private int size = 1; public Pool() { } public int getSize() { return this.size; } public void setSize(int size) { this.size = size; } } }配置线程池数量spring.task.scheduling.pool.size=5这样定时任务就有5个线程可以执行了,如果1个线程,定时任务就会阻塞。3、让定时任务执行@EnableAsync 开启异步任务功能@Async 在希望异步执行的方法开启异步执行注解,普通方法也可以使用。默认线程数8异步任务自动配置类源码:// // Source code recreated from a .class file by IntelliJ IDEA // (powered by FernFlower decompiler) // package org.springframework.boot.autoconfigure.task; import java.util.concurrent.Executor; import java.util.stream.Stream; import org.springframework.beans.factory.ObjectProvider; import org.springframework.boot.autoconfigure.condition.ConditionalOnClass; import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean; import org.springframework.boot.autoconfigure.task.TaskExecutionProperties.Pool; import org.springframework.boot.autoconfigure.task.TaskExecutionProperties.Shutdown; import org.springframework.boot.context.properties.EnableConfigurationProperties; import org.springframework.boot.task.TaskExecutorBuilder; import org.springframework.boot.task.TaskExecutorCustomizer; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.context.annotation.Lazy; import org.springframework.core.task.TaskDecorator; import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor; @ConditionalOnClass({ThreadPoolTaskExecutor.class}) @Configuration( proxyBeanMethods = false ) @EnableConfigurationProperties({TaskExecutionProperties.class}) public class TaskExecutionAutoConfiguration { public static final String APPLICATION_TASK_EXECUTOR_BEAN_NAME = "applicationTaskExecutor"; public TaskExecutionAutoConfiguration() { } @Bean @ConditionalOnMissingBean public TaskExecutorBuilder taskExecutorBuilder(TaskExecutionProperties properties, ObjectProvider<TaskExecutorCustomizer> taskExecutorCustomizers, ObjectProvider<TaskDecorator> taskDecorator) { Pool pool = properties.getPool(); TaskExecutorBuilder builder = new TaskExecutorBuilder(); builder = builder.queueCapacity(pool.getQueueCapacity()); builder = builder.corePoolSize(pool.getCoreSize()); builder = builder.maxPoolSize(pool.getMaxSize()); builder = builder.allowCoreThreadTimeOut(pool.isAllowCoreThreadTimeout()); builder = builder.keepAlive(pool.getKeepAlive()); Shutdown shutdown = properties.getShutdown(); builder = builder.awaitTermination(shutdown.isAwaitTermination()); builder = builder.awaitTerminationPeriod(shutdown.getAwaitTerminationPeriod()); builder = builder.threadNamePrefix(properties.getThreadNamePrefix()); Stream var10001 = taskExecutorCustomizers.orderedStream(); var10001.getClass(); builder = builder.customizers(var10001::iterator); builder = builder.taskDecorator((TaskDecorator)taskDecorator.getIfUnique()); return builder; } @Lazy @Bean( name = {"applicationTaskExecutor", "taskExecutor"} ) @ConditionalOnMissingBean({Executor.class}) public ThreadPoolTaskExecutor applicationTaskExecutor(TaskExecutorBuilder builder) { return builder.build(); } }默认线程8package org.springframework.boot.autoconfigure.task; import java.time.Duration; import org.springframework.boot.context.properties.ConfigurationProperties; @ConfigurationProperties("spring.task.execution") public class TaskExecutionProperties { private final TaskExecutionProperties.Pool pool = new TaskExecutionProperties.Pool(); private final TaskExecutionProperties.Shutdown shutdown = new TaskExecutionProperties.Shutdown(); private String threadNamePrefix = "task-"; public TaskExecutionProperties() { } public TaskExecutionProperties.Pool getPool() { return this.pool; } public TaskExecutionProperties.Shutdown getShutdown() { return this.shutdown; } public String getThreadNamePrefix() { return this.threadNamePrefix; } public void setThreadNamePrefix(String threadNamePrefix) { this.threadNamePrefix = threadNamePrefix; } public static class Shutdown { private boolean awaitTermination; private Duration awaitTerminationPeriod; public Shutdown() { } public boolean isAwaitTermination() { return this.awaitTermination; } public void setAwaitTermination(boolean awaitTermination) { this.awaitTermination = awaitTermination; } public Duration getAwaitTerminationPeriod() { return this.awaitTerminationPeriod; } public void setAwaitTerminationPeriod(Duration awaitTerminationPeriod) { this.awaitTerminationPeriod = awaitTerminationPeriod; } } public static class Pool { private int queueCapacity = 2147483647; private int coreSize = 8; private int maxSize = 2147483647; private boolean allowCoreThreadTimeout = true; private Duration keepAlive = Duration.ofSeconds(60L); public Pool() { } public int getQueueCapacity() { return this.queueCapacity; } public void setQueueCapacity(int queueCapacity) { this.queueCapacity = queueCapacity; } public int getCoreSize() { return this.coreSize; } public void setCoreSize(int coreSize) { this.coreSize = coreSize; } public int getMaxSize() { return this.maxSize; } public void setMaxSize(int maxSize) { this.maxSize = maxSize; } public boolean isAllowCoreThreadTimeout() { return this.allowCoreThreadTimeout; } public void setAllowCoreThreadTimeout(boolean allowCoreThreadTimeout) { this.allowCoreThreadTimeout = allowCoreThreadTimeout; } public Duration getKeepAlive() { return this.keepAlive; } public void setKeepAlive(Duration keepAlive) { this.keepAlive = keepAlive; } } }通过配置线程池线程数spring.task.execution.pool.core-size=5 spring.task.execution.pool.max-size=50实列import lombok.extern.slf4j.Slf4j; import org.springframework.scheduling.annotation.Async; import org.springframework.scheduling.annotation.EnableAsync; import org.springframework.scheduling.annotation.EnableScheduling; import org.springframework.scheduling.annotation.Scheduled; import org.springframework.stereotype.Component; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; @Slf4j @Component @EnableAsync @EnableScheduling public class MyScheduler { public static ExecutorService executorService = Executors.newFixedThreadPool(10); /** * cron表达式 */ @Async @Scheduled(cron = "1/3 1/1 * * * ? ") public void sayHell(){ System.out.println("Hello ...."); } }要用线程池的时候,自己注入即可用了。
2022年03月15日
293 阅读
0 评论
12 点赞
2022-03-11
CompletableFuture异步编排
通过线程池性能稳定,也可以获取执行结果,并捕获异常。但是,在业务复杂情况下,一个异步调用可能会依赖于另一个异步调用的执行结果。因此我们可以使用completableFuture 异步编排方案。比如:一个业务场景,需要同时获取多个数据,如果同步线程挨个执行,则需要时间为所有线程执行时间的总和。如果我们使用异步线程执行,所需时间则为耗时最长那个异步线程的执行时间。如果多个异常线程之间还存在依赖关系,比如线程3需要线程1的执行结果,线程6依赖线程3、线程2,那这个问题怎么解决呢。那就可以使用completableFuture 异步编排方案实现。注意:completableFuture 是jdk1.8之后添加的一个功能。CompletableFuture接口:public class CompletableFuture<T> implements Future<T>, CompletionStage<T> {public interface Future<V> {以前用到的FutureTask就是用到的Future可以得到返回结果public class FutureTask<V> implements RunnableFuture<V> {public interface RunnableFuture<V> extends Runnable, Future<V> { /** * Sets this Future to the result of its computation * unless it has been cancelled. */ void run(); }Future可以得到返回结果CompletableFuture随便一个方法,都接受一个Function public <U> CompletableFuture<U> applyToEither( CompletionStage<? extends T> other, Function<? super T, U> fn) { return orApplyStage(null, other, fn); }@FunctionalInterface public interface Function<T, R> {Function是一个@FunctionalInterface,所以对Lambda使用要熟悉。CompletableFuture异步编排问题多个异步线程远程调用会导致丢失请求头,原因是多个线程,通过拦截器不能获取其它线程的请求的heard信息。解决方案:每个线程共享自己的requestAttributes。自定义feign拦截器:import feign.RequestInterceptor; import feign.RequestTemplate; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.web.context.request.RequestContextHolder; import org.springframework.web.context.request.ServletRequestAttributes; import javax.servlet.http.HttpServletRequest; /** * @description: TODO * @author: <a href="mailto:batis@foxmail.com">清风</a> * @date: 2022/3/10 23:03 * @version: 1.0 */ @Configuration public class FamilyFegin { @Bean(name ="requestInterceptor") public RequestInterceptor requestInterceptor(){ return new RequestInterceptor() { @Override public void apply(RequestTemplate requestTemplate) { //RequestContextHolder拿到刚请求来的数据 ServletRequestAttributes requestAttributes = (ServletRequestAttributes)RequestContextHolder.getRequestAttributes(); System.out.println("requestAttributes线程"+Thread.currentThread().getId()); HttpServletRequest request = requestAttributes.getRequest(); System.out.println("调用feign之前"); if(request != null){ //同步请求头数据 String cookie = request.getHeader("Cookie");//老数据 //给新请求同步老请求的cookie requestTemplate.header("Cookie", cookie); } } }; } }web配置:因为需要拦截器生效import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.servlet.config.annotation.InterceptorRegistry; import org.springframework.web.servlet.config.annotation.WebMvcConfigurer; /** * @description: WEB配置 * @author: <a href="mailto:batis@foxmail.com">清风</a> * @date: 2022/3/10 22:40 * @version: 1.0 */ public class FamilyWebConfig implements WebMvcConfigurer { @Autowired LoginUserInterceptor loginUserInterceptor; @Override public void addInterceptors(InterceptorRegistry registry) { registry.addInterceptor(loginUserInterceptor).addPathPatterns("/**"); } }CompletableFuture异步编排import org.springframework.web.context.request.RequestContextHolder; import org.springframework.web.context.request.ServletRequestAttributes; import java.util.concurrent.CompletableFuture; import java.util.concurrent.ExecutionException; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; /** * @description: CompletableFuture异步编排 * @author: <a href="mailto:batis@foxmail.com">清风</a> * @date: 2022/3/10 23:32 * @version: 1.0 */ public class MyCompletableFuture { public static ExecutorService executorService = Executors.newFixedThreadPool(10); public void myOpenFeign() throws ExecutionException, InterruptedException { System.out.println("主线程0"); //远程调用存在丢失请求头的问题,因为不在同一线程,导致自定义拦截器不能获取head信息。 //解决丢失请求头方案: ServletRequestAttributes requestAttributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes(); //第一个异步任务 CompletableFuture<Void> oneFuture = CompletableFuture.runAsync(() -> { System.out.println("辅线程1"); //每个线程都共享一下自己的requestAttributes RequestContextHolder.setRequestAttributes(requestAttributes); //异步线程远程调用,业务1 //异步线程调用业务代码 }, executorService); //第二个异步任务 CompletableFuture<Void> twoFuture = CompletableFuture.runAsync(() -> { System.out.println("辅线程2"); //每个线程都共享一下自己的requestAttributes RequestContextHolder.setRequestAttributes(requestAttributes); //异步线程远程调用,业务2 //异步线程调用业务代码 }, executorService); CompletableFuture.allOf(oneFuture, twoFuture).get(); } }以上就是解决CompletableFuture异步编排,异步多线程引起的远程调用请求丢失解决方案。代码中共享requestAttributes原因ThreadLocal数据:ServletRequestAttributes requestAttributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();RequestContextHolder主线程不一样获取的数据不一样,如下:import javax.faces.context.FacesContext; import org.springframework.core.NamedInheritableThreadLocal; import org.springframework.core.NamedThreadLocal; import org.springframework.lang.Nullable; import org.springframework.util.ClassUtils; public abstract class RequestContextHolder { private static final boolean jsfPresent = ClassUtils.isPresent("javax.faces.context.FacesContext", RequestContextHolder.class.getClassLoader()); private static final ThreadLocal<RequestAttributes> requestAttributesHolder = new NamedThreadLocal("Request attributes"); private static final ThreadLocal<RequestAttributes> inheritableRequestAttributesHolder = new NamedInheritableThreadLocal("Request context"); public RequestContextHolder() { }
2022年03月11日
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