备忘5-线程池工具类

package com.alex.examples.controller.threadPool;

import org.springframework.stereotype.Component;

import javax.annotation.PostConstruct;
import java.util.concurrent.Executors;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

/**
 * 线程池管理类(饿汉模式加载:饿汉式是在类加载的时候就创建了对象实例)
 */
@Component //线程池组件化,系统启动就加载
public class ThreadPoolUtil {
    private static ThreadPoolExecutor poolExecutor = null;

    //系统启动完后,有且只执行一次
    @PostConstruct
    public void initCreate() {
        System.out.println("初始化创建线程池");
        init();
    }

    /**
     * 实例化线程池
     */
    private static void init() {
        poolExecutor = new ThreadPoolExecutor(
                8, 32, 60L, TimeUnit.SECONDS,
                new LinkedBlockingQueue<>(128), Executors.defaultThreadFactory(),
                new ThreadPoolExecutor.AbortPolicy());
    }

    /**
     * 获取线程池
     *
     * @return
     */
    public static ThreadPoolExecutor getThreadPool() {
        if (null == poolExecutor) {
            throw new RuntimeException("线程池有问题!!!!");
        }
        return poolExecutor;
    }

    /**
     * 关闭线程池（待正在执行的线程执行完后再停止，不包含等待中的线程）
     */
    public static void shutdown() {
        if (null != poolExecutor && !poolExecutor.isShutdown()) {
            poolExecutor.shutdown();
        }
    }

    /**
     * 关闭线程池（立即停止）
     */
    public static void shutdownNow() {
        if (null != poolExecutor && !poolExecutor.isShutdown()) {
            poolExecutor.shutdownNow();
        }
    }

    /**
     * 刷新线程池
     * 1.shutdown：将线程池的状态设置为SHUTWDOWN状态，正在执行的任务会继续执行下去，没有被执行的则中断。
     * 2.shutdownNow：将线程池的状态设置为STOP，正在执行的任务则被停止，没被执行任务的则返回。
     *
     * @param shutdownType:1和2
     */
    public static void refresh(Integer shutdownType) {
        if (null != poolExecutor && !poolExecutor.isShutdown()) {
            if (null == shutdownType || shutdownType.equals(1)) {
                poolExecutor.shutdown();
            } else {
                poolExecutor.shutdownNow();
            }
        }
        init(); //实例化
    }
}

private static void sendEmail(String userName) {
    ThreadPoolExecutor pool = ThreadPoolUtil.getThreadPool();
    pool.execute(() -> {
        System.out.println("给" + userName + "发送邮件通知");
    });
}