java多线程（线程池）

1、创建一个可缓存线程池，如果线程池长度超过处理需要，可灵活回收空闲线程，若无可回收，则新建线程。

public static void main(String[] args) {
 
        ExecutorService cachedThreadPool = Executors.newCachedThreadPool();
        for (int i = 0; i < 10; i++) {
            final int index = i;
            cachedThreadPool.execute(() -> {
                System.out.println("Thread.currentThread().getName() = " + Thread.currentThread().getName());
            });
        }
    }

2、创建一个固定线程数量，可重用的线程池。

public static void main(String[] args) {
        ExecutorService fixedThreadPool = Executors.newFixedThreadPool(2);
        for (int i = 0; i < 10; i++) {
            final int index = i;
            fixedThreadPool.execute(() -> {
                    System.out.println("Thread.currentThread().getName() = " + Thread.currentThread().getName());
            });
        }
    }

3、创建一个指定最多线程数量的线程池。

package com.controller;

import com.myThread.AdminThread;
import com.myThread.MyCallable;
import com.myThread.MyRunnable;
import org.springframework.web.bind.annotation.*;

import java.util.concurrent.*;

@RestController
@CrossOrigin
@RequestMapping("/admin")
public class AdminController{
    @GetMapping("/{id}")
    public long findById(@PathVariable Long id) throws InterruptedException {
        ExecutorService executorService = Executors.newFixedThreadPool(3);
        ThreadPoolExecutor pool = (ThreadPoolExecutor) executorService;
        System.out.println(pool.getPoolSize());//0
        for (int i = 0; i < 10; i++) {
            executorService.submit(()->{
                System.out.println(Thread.currentThread().getName() + "在执行了");
            });
        }
        return id;
    }
}