@Retryable重试机制

当调用其他接口失败的时候，我们希望可以多次重试调用该接口，spring中已经有封装好的相关注解，直接拿来使用即可

1 引入相关依赖

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

2.相关代码

入口类中添加@EnableRetry注解

@SpringBootApplication
@EnableRetry
public class DemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }

}

Controller

@RestController
@RequestMapping(value = "/test")
public class TestController {

    @Autowired
    private Demo1Service demo1Service;

    @GetMapping(value = "/test")
    public void test () {
        try {
            demo1Service.test();
        } catch (Exception e) {
            System.out.println("this is catch," + new Date());
        }
    }
  
}

Service

@Service
public class Demo1Service {

    // 共尝试3次调用，调用间隔5s，以后每次事件间隔*2
    @Retryable(value = {Exception.class}, maxAttempts = 3, backoff = @Backoff(value = 5000, multiplier = 2))
    public void test () {
        System.out.println("this is Demo1Service.test()，" + new Date());
        throw new RuntimeException("这里是自定义异常");
    }

    // 当在自定义的重试范围内均未调用成功，则进入到此方法中
    @Recover
    public void recover (Exception e) {
        System.out.println("this is recover(), " + e.getMessage() + "，" + new Date());
    }

}

运行结果

this is Demo1Service.test()，Sun Apr 10 15:08:00 CST 2022
this is Demo1Service.test()，Sun Apr 10 15:08:05 CST 2022
this is Demo1Service.test()，Sun Apr 10 15:08:15 CST 2022
this is recover(), 这里是自定义异常，Sun Apr 10 15:08:15 CST 2022

温馨提示： 由于retry用到了aspect增强，所有会有aspect的坑，就是方法内部调用时，会使aspect增强失效，那么retry当然也会失效。

@Service
public class Demo1Service {

    public void test () {
        // 此时test1是本类中的一个内部方法，所以test1的重试机制会失效
        // 建议将test1放到其他service中
        test1();
    }

    // 共尝试3次调用，调用间隔5s，以后每次事件间隔*2
    @Retryable(value = {Exception.class}, maxAttempts = 3, backoff = @Backoff(value = 5000, multiplier = 2))
    public void test1 () {
        System.out.println("this is Demo1Service.test1()，" + new Date());
        throw new RuntimeException("这里是自定义异常");
    }

    // 当在自定义的重试范围内均未调用成功，则进入到此方法中
    @Recover
    public void recover () {
        System.out.println("this is recover(), " + e.getMessage() + "，" + new Date());
    }

}

简单案例

@Service
public class Demo1Service {

    @Autowired
    private Demo2Service demo2Service;

    public void test () {
        Integer[] arr = {6,8,10,12,14};
        for (Integer n : arr) {
            demo2Service.test1(n);
        }
    }

}

@Service
public class Demo2Service {

    // 共尝试3次调用，调用间隔5s，以后每次事件间隔*2
    @Retryable(value = {Exception.class}, maxAttempts = 3, backoff = @Backoff(value = 5000, multiplier = 2))
    public void test1 (Integer n) {
        System.out.println("this is Demo1Service.test1()，参数:" + n + " 执行时间：" + new Date());
        if (n == 10) {
            throw new RuntimeException("这里是自定义异常");
        }
    }

    // 当在自定义的重试范围内均未调用成功，则进入到此方法中
    @Recover
    public void recover (Exception e) {
        System.out.println("this is recover(), " + e.getMessage() + "，" + new Date());
    }

}

运行结果

this is Demo1Service.test1()，参数:6 执行时间：Sun Apr 10 15:28:17 CST 2022
this is Demo1Service.test1()，参数:8 执行时间：Sun Apr 10 15:28:17 CST 2022
this is Demo1Service.test1()，参数:10 执行时间：Sun Apr 10 15:28:17 CST 2022
this is Demo1Service.test1()，参数:10 执行时间：Sun Apr 10 15:28:22 CST 2022
this is Demo1Service.test1()，参数:10 执行时间：Sun Apr 10 15:28:32 CST 2022
this is recover(), 这里是自定义异常，Sun Apr 10 15:28:32 CST 2022
this is Demo1Service.test1()，参数:12 执行时间：Sun Apr 10 15:28:32 CST 2022
this is Demo1Service.test1()，参数:14 执行时间：Sun Apr 10 15:28:32 CST 2022