[线程池] 项目中如何配置线程池

一、配置文件application.yml

# 线程池配置
thread:
  pool:
    executor:
      config:
        core-pool-size: 20
        max-pool-size: 50
        keep-alive-time: 5000
        block-queue-size: 5000
        policy: CallerRunsPolicy

二、线程池配置属性类

@Data
// 读取配置文件thread.pool.executor.config下的属性
// 忽略无法映射的属性
@ConfigurationProperties(prefix = "thread.pool.executor.config", ignoreInvalidFields = true)
public class ThreadPoolConfigProperties {

    /** 核心线程数 */
    private Integer corePoolSize = 20;
    /** 最大线程数 */
    private Integer maxPoolSize = 200;
    /** 最大等待时间 */
    private Long keepAliveTime = 10L;
    /** 最大队列数 */
    private Integer blockQueueSize = 5000;
    /*
     * AbortPolicy：丢弃任务并抛出RejectedExecutionException异常。
     * DiscardPolicy：直接丢弃任务，但是不会抛出异常
     * DiscardOldestPolicy：将最早进入队列的任务删除，之后再尝试加入队列的任务被拒绝
     * CallerRunsPolicy：如果任务添加线程池失败，那么主线程自己执行该任务
     * */
    private String policy = "AbortPolicy";

}

三、线程池配置类

@Slf4j
// 开启spring异步方法的支持，使@Async注解的方法运行在异步模式下
@EnableAsync
// 表示这个类是一个Spring配置类，用于定义配置信息和Bean
@Configuration
// 启动对ThreadPoolConfigProperties类的配置属性的支持
@EnableConfigurationProperties(ThreadPoolConfigProperties.class)
public class ThreadPoolConfig {

    // 标记该方法是bean工厂方法，返回的对象交给spring容器管理
    @Bean
    // 条件创造bean：容器中没有ThreadPoolExecutor类型的bean时才进行创建
    @ConditionalOnMissingBean(ThreadPoolExecutor.class)
    public ThreadPoolExecutor threadPoolExecutor(ThreadPoolConfigProperties properties) throws ClassNotFoundException, InstantiationException, IllegalAccessException {
        // 实例化策略
        RejectedExecutionHandler handler;
        switch (properties.getPolicy()){
            case "AbortPolicy":
                handler = new ThreadPoolExecutor.AbortPolicy();
                break;
            case "DiscardPolicy":
                handler = new ThreadPoolExecutor.DiscardPolicy();
                break;
            case "DiscardOldestPolicy":
                handler = new ThreadPoolExecutor.DiscardOldestPolicy();
                break;
            case "CallerRunsPolicy":
                handler = new ThreadPoolExecutor.CallerRunsPolicy();
                break;
            default:
                handler = new ThreadPoolExecutor.AbortPolicy();
                break;
        }
        // 创建线程池
        return new ThreadPoolExecutor(properties.getCorePoolSize(),
                properties.getMaxPoolSize(),
                properties.getKeepAliveTime(),
                TimeUnit.SECONDS,
                new LinkedBlockingQueue<>(properties.getBlockQueueSize()),
                Executors.defaultThreadFactory(),
                handler);
    }

}

四、线程池知识点回顾

(待整理)