springboot 线程池的使用

线程池可以用于解决单线程干某件事情比较慢的问题

AsyncConfigurer：通过实现AsyncConfigurer自定义线程池，包含异常处理
实现AsyncConfigurer接口对异常线程池更加细粒度的控制

步骤：*
a) 创建线程自己的线程池
b) 对void方法抛出的异常处理的类AsyncUncaughtExceptionHandler

demo

import org.springframework.aop.interceptor.AsyncUncaughtExceptionHandler;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;
import org.springframework.scheduling.annotation.AsyncConfigurer;
import org.springframework.scheduling.annotation.EnableAsync;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
import java.lang.reflect.Method;
import java.util.concurrent.Executor;
import java.util.concurrent.ThreadPoolExecutor;

/**
 * @author 
 * @version 1.0
 * <p>
 * 配置类实现AsyncConfigurer接口并重写getAsyncExecutor方法，并返回ThreadPoolTaskExecutor，
 * 这样我们就获得了一个基于线程池TaskExecutor
 */
@Configuration
@ComponentScan("com.demo") //扫描一定要包含执行类
@EnableAsync
@PropertySource(value = "classpath:application.properties", ignoreResourceNotFound = true)//手动配置目录，解决property配置找不到的问题
public class ThreadConfig implements AsyncConfigurer {

    @Override
    public Executor getAsyncExecutor() {
        ThreadPoolTaskExecutor taskExecutor = new ThreadPoolTaskExecutor();
        //核心线程数
        taskExecutor.setCorePoolSize(20);
        //队列最大长度
        taskExecutor.setQueueCapacity(1000);
        //最大线程数
        taskExecutor.setMaxPoolSize(50);
        //线程池维护线程所允许的空闲时间(单位秒)
        taskExecutor.setKeepAliveSeconds(10);
        //设置名称
        taskExecutor.setThreadNamePrefix("demo-thread");
        /*
         * 线程池对拒绝任务(无线程可用)的处理策略
         * ThreadPoolExecutor.CallerRunsPolicy策略,调用者的线程会执行该任务,如果执行器已关闭,则丢弃.
         */
        taskExecutor.setRejectedExecutionHandler(new ThreadPoolExecutor.AbortPolicy());

        taskExecutor.initialize();
        return taskExecutor;
    }
    @Override
    public AsyncUncaughtExceptionHandler getAsyncUncaughtExceptionHandler() {
        return new SpringAsyncExceptionHandler();
    }
    class SpringAsyncExceptionHandler implements AsyncUncaughtExceptionHandler {
        @Override
        public void handleUncaughtException(Throwable throwable, Method method, Object... objects) {
            System.out.println("线程池错误！" + throwable.getMessage());
        }
    }
}

线程池批量调用待执行任务对任务进行并发执行：

ExecutorService pool = Executors.newFixedThreadPool(webProcessInfo.getMaxThread());
List<Callable<Integer>> callers = new ArrayList<>();
callers.add(()->{
    crawlParseService.getChildUrls(linkurl, projectId, batchId, baseUrl, webProcessInfo, uncheckedUrlSet);
    return null;
});

//用线程池来执行callers中的批量任务
try {
    pool.invokeAll(callers);
    pool.shutdown();
}catch (InterruptedException e){
    e.printStackTrace();
}

以上