Spring Boot配置线程池拒绝策略的场景分析(妥善处理好溢出的任务)-eolink官网

Spring Boot配置线程池拒绝策略的场景分析(妥善处理好溢出的任务)

目录场景重现配置拒绝策略代码示例

通过之前三篇关于Spring Boot异步任务实现的博文，我们分别学会了用@Async创建异步任务、为异步任务配置线程池、使用多个线程池隔离不同的异步任务。今天这篇，我们继续对上面的知识进行完善和优化！

如果你已经看过上面几篇内容并已经掌握之后，一起来思考下面这个问题：

假设，线程池配置为核心线程数2、最大线程数2、缓冲队列长度2。此时，有5个异步任务同时开始，会发生什么？

场景重现

我们先来把上面的假设用代码实现一下：

第一步：创建Spring Boot应用，根据上面的假设写好线程池配置。

@EnableAsync

@SpringBootApplication

public class Chapter78Application {

public static void main(String[] args) {

SpringApplication.run(Chapter78Application.class, args);

}

@EnableAsync

@Configuration

class TaskPoolConfig {

@Bean

public Executor taskExecutor1() {

ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();

executor.setCorePoolSize(2);

executor.setMaxPoolSize(2);

executor.setQueueCapacity(2);

executor.setKeepAliveSeconds(60);

executor.setThreadNamePrefix("executor-1-");

return executor;

}

第二步：用@Async注解实现一个部分任务

@Slf4j

@Component

public class AsyncTasks {

public static Random random = new Random();

@Async("taskExecutor1")

public CompletableFuture doTaskOne(String taskNo) throws Exception {

log.info("开始任务：{}", taskNo);

long start = System.currentTimeMillis();

Thread.sleep(random.nextInt(10000));

long end = System.currentTimeMillis();

log.info("完成任务：{}，耗时：{} 毫秒", taskNo, end - start);

return CompletableFuture.completedFuture("任务完成");

}

第三步：编写测试用例

@Slf4j

@SpringBootTest

public class Chapter78ApplicationTests {

@Autowired

private AsyncTasks asyncTasks;

@Test

public void test2() throws Exception {

// 线程池配置：core-2,max-2,queue=2，同时有5个任务，出现下面异常：

// org.springframework.core.task.TaskRejectedException: Executor [java.util.concurrent.ThreadPoolExecutor@59901c4d[Running, pool size = 2,

// active threads = 0, queued tasks = 2, completed tasks = 4]] did not accept task: java.util.concurrent.CompletableFuture$AsyncSupply@408e96d9

long start = System.currentTimeMillis();

// 线程池1

CompletableFuture task1 = asyncTasks.doTaskOne("1");

CompletableFuture task2 = asyncTasks.doTaskOne("2");

CompletableFuture task3 = asyncTasks.doTaskOne("3");

CompletableFuture task4 = asyncTasks.doTaskOne("4");

CompletableFuture task5 = asyncTasks.doTaskOne("5");

// 一起执行

CompletableFuture.allOf(task1, task2, task3, task4, task5).join();

long end = System.currentTimeMillis();

log.info("任务全部完成，总耗时：" + (end - start) + "毫秒");

}

执行一下，可以类似下面这样的日志信息：

2021-09-22 17:33:08.159 INFO 21119 --- [ executor-1-2] com.didispace.chapter78.AsyncTasks : 开始任务：2

2021-09-22 17:33:08.159 INFO 21119 --- [ executor-1-1] com.didispace.chapter78.AsyncTasks : 开始任务：1

org.springframework.core.task.TaskRejectedException: Executor [java.util.concurrent.ThreadPoolExecutor@3e1a3801[Running, pool size = 2, active threads = 2, queued tasks = 2, completed tasks = 0]] did not accept task: java.util.concurrent.CompletableFuture$AsyncSupplyhttp://@64968732

at org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor.execute(ThreadPoolTaskExecutor.java:324)

at java.util.concurrent.CompletableFuture.asyncSupplyStage(CompletableFuture.java:1604)

at java.util.concurrent.CompletableFuture.supplyAsync(CompletableFuture.java:1830)

at org.springframework.aop.interceptor.AsyncExecutionAspectSupport.doSubmit(AsyncExecutionAspectSupport.java:274)

at org.springframework.aop.interceptor.AsyncExecutionInterceptor.invoke(AsyncExecutionInterceptor.java:129)

at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)

at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:750)

at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:692)

at com.didispace.chapter78.AsyncTasks$$EnhancerBySpringCGLIB$$c7e8d57b.doTaskOne()

at com.didispace.chapter78.Chapter78ApplicationTests.test2(Chapter78ApplicationTests.java:51)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.lang.reflect.Method.invoke(Method.java:498)

at org.junit.platform.commons.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:688)

at org.junit.jupiter.engine.execution.MethodInvocation.proceed(MethodInvocation.java:60)

at org.junit.jupiter.engine.execution.InvocationInterceptorChain$ValidatingInvocation.proceed(InvocationInterceptorChain.java:131)

at org.junit.jupiter.engine.extension.TimeoutExtension.intercept(TimeoutExtension.java:149)

at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestableMethod(TimeoutExtension.java:140)

at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestMethod(TimeoutExtension.java:84)

at org.junit.jupiter.engine.execution.ExecutableInvoker$ReflectiveInterceptorCall.lambda$ofVoidMethod$0(ExecutableInvoker.java:115)

at org.junit.jupiter.engine.execution.ExecutableInvoker.lambda$invoke$0(ExecutableInvoker.java:105)

at org.junit.jupiter.engine.execution.InvocationInterceptorChain$InterceptedInvocation.proceed(InvocationInterceptorChain.java:106)

at org.junit.jupiter.engine.execution.InvocationInterceptorChain.proceed(InvocationInterceptorChain.java:64)

at org.junit.jupiter.engine.execution.InvocationInterceptorChain.chainAndInvoke(InvocationInterceptorChain.java:45)

at org.junit.jupiter.engine.execution.InvocationInterceptorChain.invoke(InvocationInterceptorChain.java:37)

at org.junit.jupiter.engine.execution.ExecutableInvoker.invoke(ExecutableInvoker.java:104)

at org.junit.jupiter.engine.execution.ExecutableInvoker.invoke(ExecutableInvoker.java:98)

at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$invokeTestMethod$6(TestMethodTestDescriptor.java:210)