利用 Nacos 实现了一个动态化线程池，非常实用！

<dependency>
    <groupId>com.alibaba.cloudgroupId>
    <artifactId>spring-cloud-starter-alibaba-nacos-discoveryartifactId>
    <version>2021.1version>
dependency>
<dependency>
    <groupId>com.alibaba.cloudgroupId>
    <artifactId>spring-cloud-starter-alibaba-nacos-configartifactId>
    <version>2021.1version>
dependency>
<dependency>
    <groupId>org.springframework.bootgroupId>
    <artifactId>spring-boot-starter-webartifactId>
dependency>
<dependency>
    <groupId>org.springframework.bootgroupId>
    <artifactId>spring-boot-starterartifactId>
dependency>

server:
  port: 8010
  # 应用名称（nacos会将该名称当做服务名称）
spring:
  application:
    name: order-service
  cloud:
    nacos:
      discovery:
        namespace: public
        server-addr: 192.168.174.129:8848
      config:
        server-addr: 192.168.174.129:8848
        file-extension: yml

spring:
  profiles:
    active: dev

@RefreshScope
@Configuration
public class DynamicThreadPool implements InitializingBean {
    @Value("${core.size}")
    private String coreSize;
 
    @Value("${max.size}")
    private String maxSize;
 
    private static ThreadPoolExecutor threadPoolExecutor;
 
    @Autowired
    private NacosConfigManager nacosConfigManager;
 
    @Autowired
    private NacosConfigProperties nacosConfigProperties;
 
    @Override
    public void afterPropertiesSet() throws Exception {
        //按照nacos配置初始化线程池
        threadPoolExecutor = new ThreadPoolExecutor(Integer.parseInt(coreSize), Integer.parseInt(maxSize), 10L, TimeUnit.SECONDS,
                new LinkedBlockingQueue<>(10),
                new ThreadFactoryBuilder().setNameFormat("c_t_%d").build(),
                new RejectedExecutionHandler() {
                    @Override
                    public void rejectedExecution(Runnable r, ThreadPoolExecutor executor) {
                        System.out.println("rejected!");
                    }
                });
 
        //nacos配置变更监听
        nacosConfigManager.getConfigService().addListener("order-service-dev.yml", nacosConfigProperties.getGroup(),
                new Listener() {
                    @Override
                    public Executor getExecutor() {
                        return null;
                    }
 
                    @Override
                    public void receiveConfigInfo(String configInfo) {
                        //配置变更，修改线程池配置
                        System.out.println(configInfo);
                        changeThreadPoolConfig(Integer.parseInt(coreSize), Integer.parseInt(maxSize));
                    }
                });
    }
 
    
    public String printThreadPoolStatus() {
        return String.format("core_size:%s,thread_current_size:%s;" +
                        "thread_max_size:%s;queue_current_size:%s,total_task_count:%s", threadPoolExecutor.getCorePoolSize(),
                threadPoolExecutor.getActiveCount(), threadPoolExecutor.getMaximumPoolSize(), threadPoolExecutor.getQueue().size(),
                threadPoolExecutor.getTaskCount());
    }
 
    
    public void dynamicThreadPoolAddTask(int count) {
        for (int i = 0; i < count; i++) {
            int finalI = i;
            threadPoolExecutor.execute(new Runnable() {
                @Override
                public void run() {
                    try {
                        System.out.println(finalI);
                        Thread.sleep(10000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            });
        }
    }
 
    
    private void changeThreadPoolConfig(int coreSize, int maxSize) {
        threadPoolExecutor.setCorePoolSize(coreSize);
        threadPoolExecutor.setMaximumPoolSize(maxSize);
    }
}

@RestController
@RequestMapping("/threadpool")
public class ThreadPoolController {
 
    @Autowired
    private DynamicThreadPool dynamicThreadPool;
 
    
    @GetMapping("/print")
    public String printThreadPoolStatus() {
        return dynamicThreadPool.printThreadPoolStatus();
    }
 
    
    @GetMapping("/add")
    public String dynamicThreadPoolAddTask(int count) {
        dynamicThreadPool.dynamicThreadPoolAddTask(count);
        return String.valueOf(count);
    }
}