How SpringBoot integrates Retry to implement error retry

Introducing dependencies

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-aop</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.retry</groupId>
    <artifactId>spring-retry</artifactId>
</dependency>

Complete dependencies on pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.7.7</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!-- spring-retry -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-aop</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.retry</groupId>
            <artifactId>spring-retry</artifactId>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

Enable spring-retry

Add to startup class Annotation @EnableRetry

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

Use retry annotation

@Retryable annotation

• value, retryable exception type. The meaning is the same as include. The default is empty (if excludes is also empty, all exceptions will be retried)

• include: retryable exception types. The default is empty (if excludes is also empty, all exceptions will be retried)

• exclude: Exception types that do not need to be retried. The default is empty (if includes is also empty, all exceptions will be retried)

• maxAttempts: The maximum number of retries (including the first failure), the default is 3 times

• backoff: Retry waiting strategy, which will be introduced in @Backoff below

• recover: Indicates the callback method after the number of retries reaches the maximum number of retries

@Backoff annotation

• delay, the waiting time between retries (in milliseconds)

• maxDelay, the maximum waiting time between retries (in milliseconds)

• multiplier, specify the multiple of delay

• delayExpression , the waiting time expression between retries

• maxDelayExpression, the maximum waiting time expression between retries

• multiplierExpression, specifying the delay Multiple expression

• random, randomly specify the delay time

Usage example

package com.example.demo.component;
import org.springframework.retry.annotation.Recover;
import org.springframework.retry.annotation.Retryable;
import org.springframework.stereotype.Component;
@Component
public class HttpRequest {
    private int count = 0;
    /**
     * 模拟网络请求异常
     * @return
     */
    @Retryable(recover = "errorHandler")
    public String getResponse() {
        count++;
        System.out.println("time: " + count);
        if (count < 4) {
            throw new RuntimeException("count: " + count);
        }
        return "success";
    }
    /**
     * 错误处理函数
     * 注意：需要返回 String，否则会抛出方法找不到异常
     * org.springframework.retry.ExhaustedRetryException: Cannot locate recovery method
     *
     * @param e
     * @return
     */
    @Recover
    public String errorHandler(RuntimeException e) {
        System.out.println("errorHandler");
        return "ok";
    }
}

Test

package com.example.demo.component;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
@SpringBootTest
public class HttpRequestTest {
    @Autowired
    private HttpRequest httpRequest;
    @Test
    public void getResponse(){
        httpRequest.getResponse();
    }
}

Output result

time: 1
time: 2
time: 3
errorHandler

The above is the detailed content of How SpringBoot integrates Retry to implement error retry. For more information, please follow other related articles on the PHP Chinese website!