springboot中多线程的使用

多线程：多个线程并发的执行

1、创建配置文件

@Configuration
@EnableAsync
public class ThreadConfig {
    @Bean("doSomethingExecutor")
    public Executor doSomethingExecutor() {
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        // 核心线程数：线程池创建时候初始化的线程数
        executor.setCorePoolSize(10);
        // 最大线程数：线程池最大的线程数，只有在缓冲队列满了之后才会申请超过核心线程数的线程
        executor.setMaxPoolSize(20);
        // 缓冲队列：用来缓冲执行任务的队列
        executor.setQueueCapacity(500);
        // 允许线程的空闲时间60秒：当超过了核心线程之外的线程在空闲时间到达之后会被销毁
        executor.setKeepAliveSeconds(60);
        // 线程池名的前缀：设置好了之后可以方便我们定位处理任务所在的线程池
        executor.setThreadNamePrefix("do-something-");
        // 缓冲队列满了之后的拒绝策略：由调用线程处理（一般是主线程）
        executor.setRejectedExecutionHandler(new ThreadPoolExecutor.DiscardPolicy());
        executor.initialize();
        return executor;
    }
}

2、创建线程任务

• ThreadTaskService

public interface ThreadTestService {
    // 无返回值的线程任务
    void threadTask(int i);
    // 有返回值的线程任务
    CompletableFuture<String> threadTaskWithReturn01();
    CompletableFuture<String> threadTaskWithReturn02();
    CompletableFuture<String> threadTaskWithReturn03();
    CompletableFuture<String> threadTaskWithReturn04();
}

• ThreadTaskServiceImp

import com.baizhou.service.ThreadTestService;
import org.springframework.scheduling.annotation.Async;
import org.springframework.scheduling.annotation.EnableAsync;
import org.springframework.stereotype.Service;

import java.util.concurrent.CompletableFuture;

@Service
@EnableAsync //开启线程
public class ThreadTestServiceImp implements ThreadTestService {
    @Override
    @Async(value = "doSomethingExecutor") //声明线程任务
    public void threadTask(int i) {
        System.out.println("线程:"+Thread.currentThread().getName()+":"+i);
    }
    @Override
    @Async(value = "doSomethingExecutor") //声明线程任务
    public CompletableFuture<String> threadTaskWithReturn01() {
        return CompletableFuture.completedFuture(Thread.currentThread().getName()+":threadTaskWithReturn01()执行");
    }
    @Override
    @Async(value = "doSomethingExecutor") //声明线程任务
    public CompletableFuture<String> threadTaskWithReturn02() {
        return CompletableFuture.completedFuture(Thread.currentThread().getName()+":threadTaskWithReturn02()执行");

    }
    @Override
    @Async(value = "doSomethingExecutor") //声明线程任务
    public CompletableFuture<String> threadTaskWithReturn03() {
        return CompletableFuture.completedFuture(Thread.currentThread().getName()+":threadTaskWithReturn03()执行");

    }
    @Override
    @Async(value = "doSomethingExecutor") //声明线程任务
    public CompletableFuture<String> threadTaskWithReturn04() {
        return CompletableFuture.completedFuture(Thread.currentThread().getName()+":threadTaskWithReturn04()执行");
    }
}

3、测试

@SpringBootTest
class SpringbootMybatisPlusApplicationTests02 {
    @Autowired
    private ThreadTestService  threadTestService;
    @Test
    void ThreadTest(){
        long start=System.currentTimeMillis();
        for(int i=0;i<10;i++){
            try{
                Thread.sleep(1000);
                threadTestService.threadTask(i);//执行线程任务
            }catch (Exception e){
                throw new RuntimeException(e);
            }
        }
    }
    @Test
    void ThreadTest02() throws ExecutionException, InterruptedException {
        // 执行线程任务
        CompletableFuture<String> doSomeThing01=threadTestService.threadTaskWithReturn01();
        CompletableFuture<String> doSomeThing02=threadTestService.threadTaskWithReturn02();
        CompletableFuture<String> doSomeThing03=threadTestService.threadTaskWithReturn03();
        CompletableFuture<String> doSomeThing04=threadTestService.threadTaskWithReturn04();
        // 等待所有的线程都执行完毕
        CompletableFuture.allOf(doSomeThing01,doSomeThing02,doSomeThing03,doSomeThing04);
        //获取每个任务的返回结果
        System.out.println(doSomeThing01.get());
        System.out.println(doSomeThing02.get());
        System.out.println(doSomeThing03.get());
        System.out.println(doSomeThing04.get());
    }
}

• 结果

// 不带返回值
线程:do-something-1:0
线程:do-something-2:1
线程:do-something-3:2
线程:do-something-4:3
线程:do-something-5:4
线程:do-something-6:5
线程:do-something-7:6
线程:do-something-8:7
线程:do-something-9:8
线程:do-something-10:9
//带返回值
do-something-1:threadTaskWithReturn01()执行
do-something-2:threadTaskWithReturn02()执行
do-something-3:threadTaskWithReturn03()执行
do-something-4:threadTaskWithReturn04()执行