Spring Boot中怎么使用Spring-Retry重试框架

这篇文章主要介绍"Spring Boot中怎么使用Spring-Retry重试框架"，在日常操作中，相信很多人在Spring Boot中怎么使用Spring-Retry重试框架问题上存在疑惑，小编查阅了各式资料，整理出简单好用的操作方法，希望对大家解答"Spring Boot中怎么使用Spring-Retry重试框架"的疑惑有所帮助！接下来，请跟着小编一起来学习吧！

Spring Retry提供了自动重新调用失败的操作的功能。这在错误可能是暂时的（例如瞬时网络故障）的情况下很有用。 从2.2.0版本开始，重试功能已从Spring Batch中撤出，成为一个独立的新库：Spring Retry

Maven依赖

    org.springframework.retry    spring-retry    org.springframework    spring-aspects

注解使用

开启Retry功能

在启动类中使用@EnableRetry注解

package org.example;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.retry.annotation.EnableRetry;@SpringBootApplication@EnableRetrypublic class RetryApp {    public static void main(String[] args) {        SpringApplication.run(RetryApp.class, args);    }}

注解@Retryable

需要在重试的代码中加入重试注解@Retryable

package org.example;import lombok.extern.slf4j.Slf4j;import org.springframework.retry.annotation.Backoff;import org.springframework.retry.annotation.Recover;import org.springframework.retry.annotation.Retryable;import org.springframework.stereotype.Service;import java.time.LocalDateTime;@Service@Slf4jpublic class RetryService {    @Retryable(value = IllegalAccessException.class)    public void service1() throws IllegalAccessException {        log.info("do something... {}", LocalDateTime.now());        throw new IllegalAccessException("manual exception");    }}

默认情况下，会重试3次，间隔1秒

我们可以从注解@Retryable中看到

@Target({ ElementType.METHOD, ElementType.TYPE })@Retention(RetentionPolicy.RUNTIME)@Documentedpublic @interface Retryable {        /**         * Retry interceptor bean name to be applied for retryable method. Is mutually         * exclusive with other attributes.         * @return the retry interceptor bean name         */        String interceptor() default "";        /**         * Exception types that are retryable. Synonym for includes(). Defaults to empty (and         * if excludes is also empty all exceptions are retried).         * @return exception types to retry         */        Class[] value() default {};        /**         * Exception types that are retryable. Defaults to empty (and if excludes is also         * empty all exceptions are retried).         * @return exception types to retry         */        Class[] include() default {};        /**         * Exception types that are not retryable. Defaults to empty (and if includes is also         * empty all exceptions are retried).         * If includes is empty but excludes is not, all not excluded exceptions are retried         * @return exception types not to retry         */        Class[] exclude() default {};        /**         * A unique label for statistics reporting. If not provided the caller may choose to         * ignore it, or provide a default.         *         * @return the label for the statistics         */        String label() default "";        /**         * Flag to say that the retry is stateful: i.e. exceptions are re-thrown, but the         * retry policy is applied with the same policy to subsequent invocations with the         * same arguments. If false then retryable exceptions are not re-thrown.         * @return true if retry is stateful, default false         */        boolean stateful() default false;        /**         * @return the maximum number of attempts (including the first failure), defaults to 3         */        int maxAttempts() default 3;  //默认重试次数3次        /**         * @return an expression evaluated to the maximum number of attempts (including the first failure), defaults to 3         * Overrides {@link #maxAttempts()}.         * @since 1.2         */        String maxAttempts_Expression() default "";        /**         * Specify the backoff properties for retrying this operation. The default is a         * simple {@link Backoff} specification with no properties - see it's documentation         * for defaults.         * @return a backoff specification         */        Backoff backoff() default @Backoff(); //默认的重试中的退避策略        /**         * Specify an expression to be evaluated after the {@code SimpleRetryPolicy.canRetry()}         * returns true - can be used to conditionally suppress the retry. Only invoked after         * an exception is thrown. The root object for the evaluation is the last {@code Throwable}.         * Other beans in the context can be referenced.         * For example:         * 
         *  {@code "message.contains('you can retry this')"}.         * 
         * and         * 
         *  {@code "@someBean.shouldRetry(#root)"}.         * 
         * @return the expression.         * @since 1.2         */        String exception_Expression() default "";        /**         * Bean names of retry listeners to use instead of default ones defined in Spring context         * @return retry listeners bean names         */        String[] listeners() default {};}

@Target(ElementType.TYPE)@Retention(RetentionPolicy.RUNTIME)@Documentedpublic @interface Backoff {        /**         * Synonym for {@link #delay()}.         *         * @return the delay in milliseconds (default 1000)         */        long value() default 1000; //默认的重试间隔1秒        /**         * A canonical backoff period. Used as an initial value in the exponential case, and         * as a minimum value in the uniform case.         * @return the initial or canonical backoff period in milliseconds (default 1000)         */        long delay() default 0;        /**         * The maximimum wait (in milliseconds) between retries. If less than the         * {@link #delay()} then the default of         * {@value org.springframework.retry.backoff.ExponentialBackOffPolicy#DEFAULT_MAX_INTERVAL}         * is applied.         *         * @return the maximum delay between retries (default 0 = ignored)         */        long maxDelay() default 0;        /**         * If positive, then used as a multiplier for generating the next delay for backoff.         *         * @return a multiplier to use to calculate the next backoff delay (default 0 =         * ignored)         */        double multiplier() default 0;        /**         * An expression evaluating to the canonical backoff period. Used as an initial value         * in the exponential case, and as a minimum value in the uniform case. Overrides         * {@link #delay()}.         * @return the initial or canonical backoff period in milliseconds.         * @since 1.2         */        String delay_Expression() default "";        /**         * An expression evaluating to the maximimum wait (in milliseconds) between retries.         * If less than the {@link #delay()} then the default of         * {@value org.springframework.retry.backoff.ExponentialBackOffPolicy#DEFAULT_MAX_INTERVAL}         * is applied. Overrides {@link #maxDelay()}         *         * @return the maximum delay between retries (default 0 = ignored)         * @since 1.2         */        String maxDelay_Expression() default "";        /**         * Evaluates to a vaule used as a multiplier for generating the next delay for         * backoff. Overrides {@link #multiplier()}.         *         * @return a multiplier expression to use to calculate the next backoff delay (default         * 0 = ignored)         * @since 1.2         */        String multiplier_Expression() default "";        /**         * In the exponential case ({@link #multiplier()} > 0) set this to true to have the         * backoff delays randomized, so that the maximum delay is multiplier times the         * previous delay and the distribution is uniform between the two values.         *         * @return the flag to signal randomization is required (default false)         */        boolean random() default false;}

我们来运行测试代码

package org.example;import org.junit.jupiter.api.Test;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.boot.test.context.SpringBootTest;@SpringBootTestclass RetryServiceTest {    @Autowired    private RetryService retryService;    @Test    void testService1() throws IllegalAccessException {        retryService.service1();    }}

运行结果如下：

2021-01-05 19:40:41.221 INFO 3548 --- [ main] org.example.RetryService : do something... 2021-01-05T19:40:41.221763300
2021-01-05 19:40:42.224 INFO 3548 --- [ main] org.example.RetryService : do something... 2021-01-05T19:40:42.224436500
2021-01-05 19:40:43.225 INFO 3548 --- [ main] org.example.RetryService : do something... 2021-01-05T19:40:43.225189300

java.lang.IllegalAccessException: manual exception

at org.example.RetryService.service1(RetryService.java:19)
at org.example.RetryService$$FastClassBySpringCGLIB$$c0995ddb.invoke()
at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218)
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:769)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163)
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:747)
at org.springframework.retry.interceptor.RetryOperationsInterceptor$1.doWithRetry(RetryOperationsInterceptor.java:91)
at org.springframework.retry.support.RetryTemplate.doExecute(RetryTemplate.java:287)
at org.springframework.retry.support.RetryTemplate.execute(RetryTemplate.java:164)
at org.springframework.retry.interceptor.RetryOperationsInterceptor.invoke(RetryOperationsInterceptor.java:118)
at org.springframework.retry.annotation.AnnotationAwareRetryOperationsInterceptor.invoke(AnnotationAwareRetryOperationsInterceptor.java:153)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:747)
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:689)
at org.example.RetryService$$EnhancerBySpringCGLIB$$499afa1d.service1()
at org.example.RetryServiceTest.testService1(RetryServiceTest.java:16)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:566)
at org.junit.platform.commons.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:675)
at org.junit.jupiter.engine.execution.MethodInvocation.proceed(MethodInvocation.java:60)
at org.junit.jupiter.engine.execution.InvocationInterceptorChain$ValidatingInvocation.proceed(InvocationInterceptorChain.java:125)
at org.junit.jupiter.engine.extension.TimeoutExtension.intercept(TimeoutExtension.java:132)
at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestableMethod(TimeoutExtension.java:124)
at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestMethod(TimeoutExtension.java:74)
at org.junit.jupiter.engine.execution.ExecutableInvoker$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:104)
at org.junit.jupiter.engine.execution.InvocationInterceptorChain.proceed(InvocationInterceptorChain.java:62)
at org.junit.jupiter.engine.execution.InvocationInterceptorChain.chainAndInvoke(InvocationInterceptorChain.java:43)
at org.junit.jupiter.engine.execution.InvocationInterceptorChain.invoke(InvocationInterceptorChain.java:35)
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$6(TestMethodTestDescriptor.java:202)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.invokeTestMethod(TestMethodTestDescriptor.java:198)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:135)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:69)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$5(NodeTestTask.java:135)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$7(NodeTestTask.java:125)
at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:135)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:123)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:122)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:80)
at java.base/java.util.ArrayList.forEach(ArrayList.java:1540)
at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:38)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$5(NodeTestTask.java:139)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$7(NodeTestTask.java:125)
at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:135)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:123)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:122)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:80)
at java.base/java.util.ArrayList.forEach(ArrayList.java:1540)
at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:38)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$5(NodeTestTask.java:139)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$7(NodeTestTask.java:125)
at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:135)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:123)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:122)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:80)
at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.submit(SameThreadHierarchicalTestExecutorService.java:32)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:57)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:51)
at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:229)
at org.junit.platform.launcher.core.DefaultLauncher.lambda$execute$6(DefaultLauncher.java:197)
at org.junit.platform.launcher.core.DefaultLauncher.withInterceptedStreams(DefaultLauncher.java:211)
at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:191)
at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:128)
at com.intellij.junit5.JUnit5IdeaTestRunner.startRunnerWithArgs(JUnit5IdeaTestRunner.java:71)
at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:220)
at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:53)

可以看到重新执行了3次service1()方法，然后间隔是1秒，然后最后还是重试失败，所以抛出了异常

既然我们看到了注解@Retryable中有这么多参数可以设置，那我们就来介绍几个常用的配置。

@Retryable(include = IllegalAccessException.class, maxAttempts = 5)public void service2() throws IllegalAccessException {    log.info("do something... {}", LocalDateTime.now());    throw new IllegalAccessException("manual exception");}

首先是maxAttempts，用于设置重试次数

2021-01-06 09:30:11.263 INFO 15612 --- [ main] org.example.RetryService : do something... 2021-01-06T09:30:11.263621900
2021-01-06 09:30:12.265 INFO 15612 --- [ main] org.example.RetryService : do something... 2021-01-06T09:30:12.265629100
2021-01-06 09:30:13.265 INFO 15612 --- [ main] org.example.RetryService : do something... 2021-01-06T09:30:13.265701
2021-01-06 09:30:14.266 INFO 15612 --- [ main] org.example.RetryService : do something... 2021-01-06T09:30:14.266705400
2021-01-06 09:30:15.266 INFO 15612 --- [ main] org.example.RetryService : do something... 2021-01-06T09:30:15.266733200

java.lang.IllegalAccessException: manual exception
....

从运行结果可以看到，方法执行了5次。

下面来介绍maxAttemptsExpression的设置

@Retryable(value = IllegalAccessException.class, maxAttemptsExpression = "${maxAttempts}")public void service3() throws IllegalAccessException {    log.info("do something... {}", LocalDateTime.now());    throw new IllegalAccessException("manual exception");}

maxAttemptsExpression则可以使用表达式，比如上述就是通过获取配置中maxAttempts的值，我们可以在application.yml设置。上述其实省略掉了SpEL表达式#{....}，运行结果的话可以发现方法执行了4次..

maxAttempts: 4

我们可以使用SpEL表达式

@Retryable(value = IllegalAccessException.class, maxAttemptsExpression = "#{1+1}")public void service3_1() throws IllegalAccessException {    log.info("do something... {}", LocalDateTime.now());    throw new IllegalAccessException("manual exception");}@Retryable(value = IllegalAccessException.class, maxAttemptsExpression = "#{${maxAttempts}}")//效果和上面的一样public void service3_2() throws IllegalAccessException {    log.info("do something... {}", LocalDateTime.now());    throw new IllegalAccessException("manual exception");}

接着我们下面来看看exceptionExpression, 一样也是写SpEL表达式

@Retryable(value = IllegalAccessException.class, exceptionExpression = "message.contains('test')")public void service4(String exceptionMessage) throws IllegalAccessException {    log.info("do something... {}", LocalDateTime.now());    throw new IllegalAccessException(exceptionMessage);}    @Retryable(value = IllegalAccessException.class, exceptionExpression = "#{message.contains('test')}")public void service4_3(String exceptionMessage) throws IllegalAccessException {    log.info("do something... {}", LocalDateTime.now());    throw new IllegalAccessException(exceptionMessage);}

上面的表达式exceptionExpression = "message.contains('test')"的作用其实是获取到抛出来exception的message(调用了getMessage()方法)，然后判断message的内容里面是否包含了test字符串，如果包含的话就会执行重试。所以如果调用方法的时候传入的参数exceptionMessage中包含了test字符串的话就会执行重试。

但这里值得注意的是, Spring Retry 1.2.5之后exceptionExpression是可以省略掉#{...}

Since Spring Retry 1.2.5, for exceptionExpression, templated expressions (#{...}) are deprecated in favor of simple expression strings (message.contains('this can be retried')).

使用1.2.5之后的版本运行是没有问题的

    org.springframework.retry    spring-retry    1.3.0

但是如果使用1.2.5版本之前包括1.2.5版本的话，运行的时候会报错如下：

2021-01-06 09:52:45.209 INFO 23220 --- [ main] org.example.RetryService : do something... 2021-01-06T09:52:45.209178200

org.springframework.expression.spel.SpelEvaluationException: EL1001E: Type conversion problem, cannot convert from java.lang.String to java.lang.Boolean

at org.springframework.expression.spel.support.StandardTypeConverter.convertValue(StandardTypeConverter.java:75)
at org.springframework.expression.common.ExpressionUtils.convertTypedValue(ExpressionUtils.java:57)
at org.springframework.expression.common.LiteralExpression.getValue(LiteralExpression.java:106)
at org.springframework.retry.policy.ExpressionRetryPolicy.canRetry(ExpressionRetryPolicy.java:113)
at org.springframework.retry.support.RetryTemplate.canRetry(RetryTemplate.java:375)
at org.springframework.retry.support.RetryTemplate.doExecute(RetryTemplate.java:304)
at org.springframework.retry.support.RetryTemplate.execute(RetryTemplate.java:164)
at org.springframework.retry.interceptor.RetryOperationsInterceptor.invoke(RetryOperationsInterceptor.java:118)
at org.springframework.retry.annotation.AnnotationAwareRetryOperationsInterceptor.invoke(AnnotationAwareRetryOperationsInterceptor.java:153)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:749)
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:691)
at org.example.RetryService$$EnhancerBySpringCGLIB$$d321a75e.service4()
at org.example.RetryServiceTest.testService4_2(RetryServiceTest.java:46)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:566)
at org.junit.platform.commons.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:686)
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$6(TestMethodTestDescriptor.java:212)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.invokeTestMethod(TestMethodTestDescriptor.java:208)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:137)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:71)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$5(NodeTestTask.java:135)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$7(NodeTestTask.java:125)
at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:135)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:123)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:122)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:80)
at java.base/java.util.ArrayList.forEach(ArrayList.java:1540)
at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:38)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$5(NodeTestTask.java:139)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$7(NodeTestTask.java:125)
at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:135)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:123)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:122)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:80)
at java.base/java.util.ArrayList.forEach(ArrayList.java:1540)
at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:38)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$5(NodeTestTask.java:139)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$7(NodeTestTask.java:125)
at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:135)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:123)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:122)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:80)
at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.submit(SameThreadHierarchicalTestExecutorService.java:32)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:57)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:51)
at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:248)
at org.junit.platform.launcher.core.DefaultLauncher.lambda$execute$5(DefaultLauncher.java:211)
at org.junit.platform.launcher.core.DefaultLauncher.withInterceptedStreams(DefaultLauncher.java:226)
at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:199)
at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:132)
at com.intellij.junit5.JUnit5IdeaTestRunner.startRunnerWithArgs(JUnit5IdeaTestRunner.java:71)
at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:220)
at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:53)
Caused by: org.springframework.core.convert.ConversionFailedException: Failed to convert from type [java.lang.String] to type [java.lang.Boolean] for value 'message.contains('test')'; nested exception is java.lang.IllegalArgumentException: Invalid boolean value 'message.contains('test')'
at org.springframework.core.convert.support.ConversionUtils.invokeConverter(ConversionUtils.java:47)
at org.springframework.core.convert.support.GenericConversionService.convert(GenericConversionService.java:191)
at org.springframework.expression.spel.support.StandardTypeConverter.convertValue(StandardTypeConverter.java:70)
... 76 more
Caused by: java.lang.IllegalArgumentException: Invalid boolean value 'message.contains('test')'
at org.springframework.core.convert.support.StringToBooleanConverter.convert(StringToBooleanConverter.java:63)
at org.springframework.core.convert.support.StringToBooleanConverter.convert(StringToBooleanConverter.java:31)
at org.springframework.core.convert.support.GenericConversionService$ConverterAdapter.convert(GenericConversionService.java:385)
at org.springframework.core.convert.support.ConversionUtils.invokeConverter(ConversionUtils.java:41)
... 78 more

还可以在表达式中执行一个方法，前提是方法的类在spring容器中注册了，@retryService其实就是获取bean name为retryService的bean，然后调用里面的checkException方法，传入的参数为#root，它其实就是抛出来的exception对象。一样的也是可以省略#{...}

    @Retryable(value = IllegalAccessException.class, exceptionExpression = "#{@retryService.checkException(#root)}")    public void service5(String exceptionMessage) throws IllegalAccessException {        log.info("do something... {}", LocalDateTime.now());        throw new IllegalAccessException(exceptionMessage);    }    @Retryable(value = IllegalAccessException.class, exceptionExpression = "@retryService.checkException(#root)")    public void service5_1(String exceptionMessage) throws IllegalAccessException {        log.info("do something... {}", LocalDateTime.now());        throw new IllegalAccessException(exceptionMessage);    }        public boolean checkException(Exception e) {        log.error("error message:{}", e.getMessage());        return true; //返回true的话表明会执行重试，如果返回false则不会执行重试    }

运行结果：

2021-01-06 13:33:52.913 INFO 23052 --- [ main] org.example.RetryService : do something... 2021-01-06T13:33:52.913404
2021-01-06 13:33:52.981 ERROR 23052 --- [ main] org.example.RetryService : error message:test message
2021-01-06 13:33:53.990 ERROR 23052 --- [ main] org.example.RetryService : error message:test message
2021-01-06 13:33:53.990 INFO 23052 --- [ main] org.example.RetryService : do something... 2021-01-06T13:33:53.990947400
2021-01-06 13:33:53.990 ERROR 23052 --- [ main] org.example.RetryService : error message:test message
2021-01-06 13:33:54.992 ERROR 23052 --- [ main] org.example.RetryService : error message:test message
2021-01-06 13:33:54.992 INFO 23052 --- [ main] org.example.RetryService : do something... 2021-01-06T13:33:54.992342900

当然还有更多表达式的用法了...

  @Retryable(exceptionExpression = "#{#root instanceof T(java.lang.IllegalAccessException)}") //判断exception的类型    public void service5_2(String exceptionMessage) {        log.info("do something... {}", LocalDateTime.now());        throw new NullPointerException(exceptionMessage);    }    @Retryable(exceptionExpression = "#root instanceof T(java.lang.IllegalAccessException)")    public void service5_3(String exceptionMessage) {        log.info("do something... {}", LocalDateTime.now());        throw new NullPointerException(exceptionMessage);    }

    @Retryable(exceptionExpression = "myMessage.contains('test')") //查看自定义的MyException中的myMessage的值是否包含test字符串    public void service5_4(String exceptionMessage) throws MyException {        log.info("do something... {}", LocalDateTime.now());        throw new MyException(exceptionMessage); //自定义的exception    }    @Retryable(exceptionExpression = "#root.myMessage.contains('test')")  //和上面service5_4方法的效果一样    public void service5_5(String exceptionMessage) throws MyException {        log.info("do something... {}", LocalDateTime.now());        throw new MyException(exceptionMessage);    }

package org.example;import lombok.Getter;import lombok.Setter;@Getter@Setterpublic class MyException extends Exception {    private String myMessage;    public MyException(String myMessage) {        this.myMessage = myMessage;    }}

下面再来看看另一个配置exclude

  @Retryable(exclude = MyException.class)    public void service6(String exceptionMessage) throws MyException {        log.info("do something... {}", LocalDateTime.now());        throw new MyException(exceptionMessage);    }

这个exclude属性可以帮我们排除一些我们不想重试的异常

最后我们来看看这个backoff 重试等待策略, 默认使用@Backoff注解。

我们先来看看这个@Backoff的value属性,用于设置重试间隔

 @Retryable(value = IllegalAccessException.class,            backoff = @Backoff(value = 2000))    public void service7() throws IllegalAccessException {        log.info("do something... {}", LocalDateTime.now());        throw new IllegalAccessException();    }

运行结果可以看出来重试的间隔为2秒

2021-01-06 14:47:38.036 INFO 21116 --- [ main] org.example.RetryService : do something... 2021-01-06T14:47:38.036732600
2021-01-06 14:47:40.038 INFO 21116 --- [ main] org.example.RetryService : do something... 2021-01-06T14:47:40.037753600
2021-01-06 14:47:42.046 INFO 21116 --- [ main] org.example.RetryService : do something... 2021-01-06T14:47:42.046642900

java.lang.IllegalAccessException
at org.example.RetryService.service7(RetryService.java:113)
...

接下来介绍@Backoff的delay属性，它与value属性不能共存，当delay不设置的时候会去读value属性设置的值，如果delay设置的话则会忽略value属性

@Retryable(value = IllegalAccessException.class,            backoff = @Backoff(value = 2000,delay = 500))    public void service8() throws IllegalAccessException {        log.info("do something... {}", LocalDateTime.now());        throw new IllegalAccessException();    }

运行结果可以看出，重试的时间间隔为500ms

2021-01-06 15:22:42.271 INFO 13512 --- [ main] org.example.RetryService : do something... 2021-01-06T15:22:42.271504800
2021-01-06 15:22:42.772 INFO 13512 --- [ main] org.example.RetryService : do something... 2021-01-06T15:22:42.772234900
2021-01-06 15:22:43.273 INFO 13512 --- [ main] org.example.RetryService : do something... 2021-01-06T15:22:43.273246700

java.lang.IllegalAccessException
at org.example.RetryService.service8(RetryService.java:121)

接下来我们来看``@Backoff的multiplier`的属性, 指定延迟倍数, 默认为0。

@Retryable(value = IllegalAccessException.class,maxAttempts = 4,            backoff = @Backoff(delay = 2000, multiplier = 2))    public void service9() throws IllegalAccessException {        log.info("do something... {}", LocalDateTime.now());        throw new IllegalAccessException();    }

multiplier设置为2，则表示第一次重试间隔为2s，第二次为4秒，第三次为8s

运行结果如下：

2021-01-06 15:58:07.458 INFO 23640 --- [ main] org.example.RetryService : do something... 2021-01-06T15:58:07.458245500
2021-01-06 15:58:09.478 INFO 23640 --- [ main] org.example.RetryService : do something... 2021-01-06T15:58:09.478681300
2021-01-06 15:58:13.478 INFO 23640 --- [ main] org.example.RetryService : do something... 2021-01-06T15:58:13.478921900
2021-01-06 15:58:21.489 INFO 23640 --- [ main] org.example.RetryService : do something... 2021-01-06T15:58:21.489240600

java.lang.IllegalAccessException
at org.example.RetryService.service9(RetryService.java:128)
...

接下来我们来看看这个@Backoff的maxDelay属性,设置最大的重试间隔，当超过这个最大的重试间隔的时候，重试的间隔就等于maxDelay的值

@Retryable(value = IllegalAccessException.class,maxAttempts = 4,            backoff = @Backoff(delay = 2000, multiplier = 2,maxDelay = 5000))    public void service10() throws IllegalAccessException {        log.info("do something... {}", LocalDateTime.now());        throw new IllegalAccessException();    }

运行结果：

2021-01-06 16:12:37.377 INFO 5024 --- [ main] org.example.RetryService : do something... 2021-01-06T16:12:37.377616100
2021-01-06 16:12:39.381 INFO 5024 --- [ main] org.example.RetryService : do something... 2021-01-06T16:12:39.381299400
2021-01-06 16:12:43.382 INFO 5024 --- [ main] org.example.RetryService : do something... 2021-01-06T16:12:43.382169500
2021-01-06 16:12:48.396 INFO 5024 --- [ main] org.example.RetryService : do something... 2021-01-06T16:12:48.396327600

java.lang.IllegalAccessException
at org.example.RetryService.service10(RetryService.java:135)

可以最后的最大重试间隔是5秒

注解@Recover

当@Retryable方法重试失败之后，最后就会调用@Recover方法。用于@Retryable失败时的"兜底"处理方法。 @Recover的方法必须要与@Retryable注解的方法保持一致，第一入参为要重试的异常，其他参数与@Retryable保持一致，返回值也要一样，否则无法执行！

      @Retryable(value = IllegalAccessException.class)    public void service11() throws IllegalAccessException {        log.info("do something... {}", LocalDateTime.now());        throw new IllegalAccessException();    }    @Recover    public void recover11(IllegalAccessException e) {        log.info("service retry after Recover => {}", e.getMessage());    }    //=========================    @Retryable(value = ArithmeticException.class)    public int service12() throws IllegalAccessException {        log.info("do something... {}", LocalDateTime.now());        return 1 / 0;    }    @Recover    public int recover12(ArithmeticException e) {        log.info("service retry after Recover => {}", e.getMessage());        return 0;    }    //=========================    @Retryable(value = ArithmeticException.class)    public int service13(String message) throws IllegalAccessException {        log.info("do something... {},{}", message, LocalDateTime.now());        return 1 / 0;    }    @Recover    public int recover13(ArithmeticException e, String message) {        log.info("{},service retry after Recover => {}", message, e.getMessage());        return 0;    }

注解@CircuitBreaker

熔断模式：指在具体的重试机制下失败后打开断路器，过了一段时间，断路器进入半开状态，允许一个进入重试，若失败再次进入断路器，成功则关闭断路器，注解为@CircuitBreaker,具体包括熔断打开时间、重置过期时间

  // openTimeout时间范围内失败maxAttempts次数后，熔断打开resetTimeout时长         @CircuitBreaker(openTimeout = 1000, resetTimeout = 3000, value = NullPointerException.class)    public void circuitBreaker(int num) {        log.info(" 进入断路器方法num={}", num);        if (num > 8) return;        Integer n = null;        System.err.println(1 / n);    }    @Recover    public void recover(NullPointerException e) {        log.info("service retry after Recover => {}", e.getMessage());    }

测试方法

     @Test    public void testCircuitBreaker() throws InterruptedException {        System.err.println("尝试进入断路器方法，并触发异常...");        retryService.circuitBreaker(1);        retryService.circuitBreaker(1);        retryService.circuitBreaker(9);        retryService.circuitBreaker(9);        System.err.println("在openTimeout 1秒之内重试次数为2次，未达到触发熔断, 断路器依然闭合...");        TimeUnit.SECONDS.sleep(1);        System.err.println("超过openTimeout 1秒之后, 因为未触发熔断，所以重试次数重置，可以正常访问...,继续重试3次方法...");        retryService.circuitBreaker(1);        retryService.circuitBreaker(1);        retryService.circuitBreaker(1);        System.err.println("在openTimeout 1秒之内重试次数为3次，达到触发熔断，不会执行重试，只会执行恢复方法...");        retryService.circuitBreaker(1);        TimeUnit.SECONDS.sleep(2);        retryService.circuitBreaker(9);        TimeUnit.SECONDS.sleep(3);        System.err.println("超过resetTimeout 3秒之后，断路器重新闭合...,可以正常访问");        retryService.circuitBreaker(9);        retryService.circuitBreaker(9);        retryService.circuitBreaker(9);        retryService.circuitBreaker(9);        retryService.circuitBreaker(9);    }

运行结果：

尝试进入断路器方法，并触发异常...
2021-01-07 21:44:20.842 INFO 7464 --- [ main] org.example.RetryService : 进入断路器方法num=1
2021-01-07 21:44:20.844 INFO 7464 --- [ main] org.example.RetryService : service retry after Recover => null
2021-01-07 21:44:20.845 INFO 7464 --- [ main] org.example.RetryService : 进入断路器方法num=1
2021-01-07 21:44:20.845 INFO 7464 --- [ main] org.example.RetryService : service retry after Recover => null
2021-01-07 21:44:20.845 INFO 7464 --- [ main] org.example.RetryService : 进入断路器方法num=9
2021-01-07 21:44:20.845 INFO 7464 --- [ main] org.example.RetryService : 进入断路器方法num=9
在openTimeout 1秒之内重试次数为2次，未达到触发熔断, 断路器依然闭合...
超过openTimeout 1秒之后, 因为未触发熔断，所以重试次数重置，可以正常访问...,继续重试3次方法...
2021-01-07 21:44:21.846 INFO 7464 --- [ main] org.example.RetryService : 进入断路器方法num=1
2021-01-07 21:44:21.847 INFO 7464 --- [ main] org.example.RetryService : service retry after Recover => null
2021-01-07 21:44:21.847 INFO 7464 --- [ main] org.example.RetryService : 进入断路器方法num=1
2021-01-07 21:44:21.847 INFO 7464 --- [ main] org.example.RetryService : service retry after Recover => null
2021-01-07 21:44:21.847 INFO 7464 --- [ main] org.example.RetryService : 进入断路器方法num=1
2021-01-07 21:44:21.848 INFO 7464 --- [ main] org.example.RetryService : service retry after Recover => null
在openTimeout 1秒之内重试次数为3次，达到触发熔断，不会执行重试，只会执行恢复方法...
2021-01-07 21:44:21.848 INFO 7464 --- [ main] org.example.RetryService : service retry after Recover => null
2021-01-07 21:44:23.853 INFO 7464 --- [ main] org.example.RetryService : service retry after Recover => null
超过resetTimeout 3秒之后，断路器重新闭合...,可以正常访问
2021-01-07 21:44:26.853 INFO 7464 --- [ main] org.example.RetryService : 进入断路器方法num=9
2021-01-07 21:44:26.854 INFO 7464 --- [ main] org.example.RetryService : 进入断路器方法num=9
2021-01-07 21:44:26.855 INFO 7464 --- [ main] org.example.RetryService : 进入断路器方法num=9
2021-01-07 21:44:26.855 INFO 7464 --- [ main] org.example.RetryService : 进入断路器方法num=9
2021-01-07 21:44:26.856 INFO 7464 --- [ main] org.example.RetryService : 进入断路器方法num=9

RetryTemplate

RetryTemplate配置

package org.example;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.retry.backoff.FixedBackOffPolicy;import org.springframework.retry.policy.SimpleRetryPolicy;import org.springframework.retry.support.RetryTemplate;@Configurationpublic class AppConfig {       @Bean    public RetryTemplate retryTemplate() {        RetryTemplate retryTemplate = new RetryTemplate();        SimpleRetryPolicy retryPolicy = new SimpleRetryPolicy(); //设置重试策略        retryPolicy.setMaxAttempts(2);        retryTemplate.setRetryPolicy(retryPolicy);        FixedBackOffPolicy fixedBackOffPolicy = new FixedBackOffPolicy(); //设置退避策略        fixedBackOffPolicy.setBackOffPeriod(2000L);        retryTemplate.setBackOffPolicy(fixedBackOffPolicy);                        return retryTemplate;    }}

可以看到这些配置跟我们直接写注解的方式是差不多的，这里就不过多的介绍了。。

使用RetryTemplate

package org.example;import org.junit.jupiter.api.Test;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.boot.test.context.SpringBootTest;import org.springframework.retry.RetryCallback;import org.springframework.retry.RetryContext;import org.springframework.retry.support.RetryTemplate;@SpringBootTestpublic class RetryTemplateTest {    @Autowired    private RetryTemplate retryTemplate;    @Autowired    private RetryTemplateService retryTemplateService;    @Test    void test1() throws IllegalAccessException {        retryTemplate.execute(new RetryCallback() {            @Override            public Object doWithRetry(RetryContext context) throws IllegalAccessException {                 retryTemplateService.service1();                return null;            }        });    }        @Test    void test2() throws IllegalAccessException {        retryTemplate.execute(new RetryCallback() {            @Override            public Object doWithRetry(RetryContext context) throws IllegalAccessException {                retryTemplateService.service1();                return null;            }        }, new RecoveryCallback