在post请求接口中,由于耗时任务处理时间过长,接口返回不可能一直等待业务逻辑处理完全才返回给前端,这时必须使用线程池来处理耗时任务,然后接口直接返回。通过异步处理的方式处理数据。
由于是SpringBoot项目,最终决定使用线程池ThreadPoolExecutor,可以利用Spring提供的对ThreadPoolExecutor封装的线程池ThreadPoolTaskExecutor,直接使用注解启用。
1、配置类编写
先创建一个线程池的配置,让SpringBoot加载,用来定义如何创建一个ThreadPoolTaskExecutor线程池,要使用 @Configuration 和@EnableAsync 这两个注解,表示这是个配置类,并且是线程池的配置类。
/**
* @Author:hutao2
* @Date: 2010/11/27 22:01
*/
@Configuration
@EnableAsync
public class ExecutorConfig {
private static final Logger logger = LoggerFactory.getLogger(ExecutorConfig.class);
//这里在配置文件(application.yml)中进行配置
//本例中为了方便将配置写死了
private int corePoolSize = 10;
private int maxPoolSize = 10;
private int queueCapacity = 99999;
private String namePrefix = ocr-Thread-;
@Bean(name = "asyncServiceExecutor")
public Executor asyncServiceExecutor() {
logger.info("start asyncServiceExecutor");
//ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
ThreadPoolTaskExecutor executor = new VisiableThreadPoolTaskExecutor();//用自定义的子类,可以展示线程池的状况
//配置核心线程数
executor.setCorePoolSize(corePoolSize);
//配置最大线程数
executor.setMaxPoolSize(maxPoolSize);
//配置队列大小
executor.setQueueCapacity(queueCapacity);
//配置线程池中的线程的名称前缀
executor.setThreadNamePrefix(namePrefix);
// rejection-policy:当pool已经达到max size的时候,如何处理新任务
// CALLER_RUNS:不在新线程中执行任务,而是有调用者所在的线程来执行
executor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
//执行初始化
executor.initialize();
return executor;
}
}
2、ThreadPoolTaskExecutor的子类编写
为了展示线程池当时的情况,有多少线程在执行,多少在队列中等待,要创建了一个ThreadPoolTaskExecutor的子类,在每次提交线程的时候都会将当前线程池的运行状况打印出来。
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
import org.springframework.util.concurrent.ListenableFuture;
import java.util.concurrent.Callable;
import java.util.concurrent.Future;
import java.util.concurrent.ThreadPoolExecutor;
/**
* @Author:hutao2
* @Date: 2010/11/27 22:19
*/
public class VisiableThreadPoolTaskExecutor extends ThreadPoolTaskExecutor {
private static final Logger logger = LoggerFactory.getLogger(VisiableThreadPoolTaskExecutor.class);
private void showThreadPoolInfo(String prefix) {
ThreadPoolExecutor threadPoolExecutor = getThreadPoolExecutor();
if (null == threadPoolExecutor) {
return;
}
logger.info("{}, {},taskCount [{}], completedTaskCount [{}], activeCount [{}], queueSize [{}]",
this.getThreadNamePrefix(),
prefix,
threadPoolExecutor.getTaskCount(),
threadPoolExecutor.getCompletedTaskCount(),
threadPoolExecutor.getActiveCount(),
threadPoolExecutor.getQueue().size());
}
@Override
public void execute(Runnable task) {
showThreadPoolInfo("1. do execute");
super.execute(task);
}
@Override
public void execute(Runnable task, long startTimeout) {
showThreadPoolInfo("2. do execute");
super.execute(task, startTimeout);
}
@Override
public Future<?> submit(Runnable task) {
showThreadPoolInfo("1. do submit");
return super.submit(task);
}
@Override
public <T> Future<T> submit(Callable<T> task) {
showThreadPoolInfo("2. do submit");
return super.submit(task);
}
@Override
public ListenableFuture<?> submitListenable(Runnable task) {
showThreadPoolInfo("1. do submitListenable");
return super.submitListenable(task);
}
@Override
public <T> ListenableFuture<T> submitListenable(Callable<T> task) {
showThreadPoolInfo("2. do submitListenable");
return super.submitListenable(task);
}
}
3、Service接口以及实现类(demo)
创建一个Service接口(异步线程执行的耗时操作)以及Service的实现类(ServiceImpl)
public interface AsyncService {
/**
* 执行异步任务
* 可以根据需求,自己加参数拟定,我这里就做个测试演示
*/
void executeAsync();
}
将Service层的服务异步化,在executeAsync()方法上增加注解@Async(“asyncServiceExecutor”),asyncServiceExecutor方法是前面ExecutorConfig.java中的方法名,表明executeAsync方法进入的线程池是asyncServiceExecutor方法创建的。
@Service
public class AsyncServiceImpl implements AsyncService {
private static final Logger logger = LoggerFactory.getLogger(AsyncServiceImpl.class);
@Override
@Async("asyncServiceExecutor")
public void executeAsync() {
logger.info("start executeAsync");
System.out.println("异步线程要做的事情");
System.out.println("可以在这里执行批量插入等耗时的事情");
logger.info("end executeAsync");
}
}
4、在Controller里通过@Autowired注入上面的Service
@Autowired
private AsyncService asyncService;
@GetMapping("/async")
public void async(){
asyncService.executeAsync();
}
5、使用测试工具发起请求观察控制台
2019-12-29 22:23:30.951 INFO 14088 --- [nio-8087-exec-2] u.d.e.e.i.VisiableThreadPoolTaskExecutor : ocr-Thread-, 2. do submit,taskCount [0], completedTaskCount [0], activeCount [0], queueSize [0]
2019-12-29 22:23:30.952 INFO 14088 --- [ocr-Thread-1] c.u.d.e.executor.impl.AsyncServiceImpl : start executeAsync
异步线程要做的事情
可以在这里执行批量插入等耗时的事情
2019-12-29 22:23:30.953 INFO 14088 --- [ocr-Thread-1] c.u.d.e.executor.impl.AsyncServiceImpl : end executeAsync
2019-12-29 22:23:31.351 INFO 14088 --- [nio-8087-exec-3] u.d.e.e.i.VisiableThreadPoolTaskExecutor : ocr-Thread-, 2. do submit,taskCount [1], completedTaskCount [1], activeCount [0], queueSize [0]
2019-12-29 22:23:31.353 INFO 14088 --- [ocr-Thread-2] c.u.d.e.executor.impl.AsyncServiceImpl : start executeAsync
异步线程要做的事情
可以在这里执行批量插入等耗时的事情
2019-12-29 22:23:31.353 INFO 14088 --- [ocr-Thread-2] c.u.d.e.executor.impl.AsyncServiceImpl : end executeAsync
2019-12-29 22:23:31.927 INFO 14088 --- [nio-8087-exec-5] u.d.e.e.i.VisiableThreadPoolTaskExecutor : ocr-Thread-, 2. do submit,taskCount [2], completedTaskCount [2], activeCount [0], queueSize [0]
2019-12-29 22:23:31.929 INFO 14088 --- [ocr-Thread-3] c.u.d.e.executor.impl.AsyncServiceImpl : start executeAsync
异步线程要做的事情
可以在这里执行批量插入等耗时的事情
2019-12-29 22:23:31.930 INFO 14088 --- [ocr-Thread-3] c.u.d.e.executor.impl.AsyncServiceImpl : end executeAsync
2019-12-29 22:23:32.496 INFO 14088 --- [nio-8087-exec-7] u.d.e.e.i.VisiableThreadPoolTaskExecutor : ocr-Thread-, 2. do submit,taskCount [3], completedTaskCount [3], activeCount [0], queueSize [0]
2019-12-29 22:23:32.498 INFO 14088 --- [ocr-Thread-4] c.u.d.e.executor.impl.AsyncServiceImpl : start executeAsync
异步线程要做的事情
可以在这里执行批量插入等耗时的事情
2019-12-29 22:23:32.499 INFO 14088 --- [ocr-Thread-4] c.u.d.e.executor.impl.AsyncServiceImpl : end executeAsync
本次问题是在工作中处理文档识别中碰到的,记录一下线程池的使用。具体内容由于代码在内网环境中以及代码不能公开的原因,我就使用了一个网上的学习例子来记录。关键是能够使用线程池处理问题。
参考网站:SpringBoot线程池的使用