异步执行

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部分代码来自《spring cloud 微服务 入门、进阶与实战》

简单使用

spring 中想要方法是异步执行只需要加上@Async注解即可

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@Component
public class MyAsyncMethod {
    @Async
    public void test1() throws InterruptedException {
        int i = 0;
        while (i<5){
            System.out.println(i);
            i++;
        }
    }
    public void test2() throws InterruptedException {
        System.out.println("test222222");
                    Thread.sleep(10L);
        System.out.println("test333333");
    }
}
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myAsyncMethod.test1();
myAsyncMethod.test2();

控制台输出

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test222222
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test333333

配置线程池

有时我们想要自定义线程池的参数我们可增加如下配置

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@Configuration
@ConfigurationProperties(prefix = "spring.task.pool")
public class TaskThreadPoolConfig {

    /**核心线程数*/
    private int corePoolSize = 5;

    /**最大线程数*/
    private int maxPoolSize = 50;

    /**线程池维护线程所允许的空闲时间*/
    private int keepAliveSeconds = 60;

    /**队列长度*/
    private int queueCapacity = 10000;

    /**线程名称前缀*/
    private String threadNamePrefix = "FSH-AsyncTask-";
}
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@Configuration
public class AsyncTaskExecutePool implements AsyncConfigurer {
    private Logger logger = LoggerFactory.getLogger(AsyncTaskExecutePool.class);

    @Autowired
    private TaskThreadPoolConfig config;

    @Override
    public Executor getAsyncExecutor() {
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        executor.setCorePoolSize(config.getCorePoolSize());
        executor.setMaxPoolSize(config.getMaxPoolSize());
        executor.setQueueCapacity(config.getQueueCapacity());
        executor.setKeepAliveSeconds(config.getKeepAliveSeconds());
        executor.setThreadNamePrefix(config.getThreadNamePrefix());
        /**
         * 线程池拒绝策略：如果不配置并超过了负荷会造成溢出
         * AbortPolicy:直接抛出异常  会丢弃任务
         * CallerRunsPolicy 先由主线程执行当前任务，下个任务继续交给线程池来执行
         */
        executor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
        executor.initialize();
        return executor;
    }
    @Override
    public AsyncUncaughtExceptionHandler getAsyncUncaughtExceptionHandler() {
        // 异步任务中异常处理
        return new AsyncUncaughtExceptionHandler() {
            @Override
            public void handleUncaughtException(Throwable arg0, Method arg1, Object... arg2) {

                logger.error("==========================" + arg0.getMessage() + "=======================", arg0);
                logger.error("exception method:" + arg1.getName());
            }
        };
    }
}

然后在配置文件中配置相关参数

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spring.task.pool.corePoolSize=9

注意

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异步执行方法需在外部调用，在异步类中通过 this.xxx() 方式调用会无效