Java SpringBoot @Async实现异步任务的流程分析

Olivia ·

更新时间:2024-11-10

· 901 次阅读

1、同步任务

2、@Async 异步任务-无返回值

3、@Async 异步任务-有返回值

4、@Async + 自定义线程池

5、CompletableFuture 实现异步任务

依赖pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.7.7</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.example</groupId>
<artifactId>demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>demo</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<scope>runtime</scope>
<optional>true</optional>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<configuration>
<excludes>
<exclude>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</exclude>
</excludes>
</configuration>
</plugin>
</plugins>
</build>
</project>

1、同步任务

应用启动类

package com.example.demo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}

同步任务，耗时2秒

package com.example.demo.service;
import lombok.extern.slf4j.Slf4j;
import org.springframework.scheduling.annotation.Async;
import org.springframework.scheduling.annotation.AsyncResult;
import org.springframework.stereotype.Service;
import java.util.concurrent.Future;
@Service
@Slf4j
public class TaskService {
    /**
     * 同步任务
     * @throws InterruptedException
     */
    public void syncTask() throws InterruptedException {
        Thread.sleep(1000 * 2);
        System.out.println("syncTask");
    }
}

控制器

package com.example.demo.controller;
import com.example.demo.service.TaskService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
@RestController
@RequestMapping("/task")
@Slf4j
public class TaskController {
    @Autowired
    private TaskService taskService;
    @GetMapping("/syncTask")
    public String syncTask() throws InterruptedException {
        long start = System.currentTimeMillis();
        taskService.syncTask();
        long end = System.currentTimeMillis();
        log.info("time: {}", end - start);
        return "success";
    }
}

请求接口：等待2秒后返回

GET http://localhost:8080/task/syncTask
Accept: application/json·

2、@Async 异步任务-无返回值

启动类需要加上注解：@EnableAsync

package com.example.demo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.scheduling.annotation.EnableAsync;
@SpringBootApplication
@EnableAsync
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}

异步任务

package com.example.demo.service;
import lombok.extern.slf4j.Slf4j;
import org.springframework.scheduling.annotation.Async;
import org.springframework.scheduling.annotation.AsyncResult;
import org.springframework.stereotype.Service;
import java.util.concurrent.Future;
@Service
@Slf4j
public class TaskService {
    /**
     * 异步任务
     * @throws InterruptedException
     */
    @Async
    public void asyncTask() throws InterruptedException {
        Thread.sleep(1000 * 2);
        System.out.println("asyncTask");
    }
}

控制器

package com.example.demo.controller;
import com.example.demo.service.TaskService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
@RestController
@RequestMapping("/task")
@Slf4j
public class TaskController {
    @Autowired
    private TaskService taskService;
    @GetMapping("/asyncTask")
    public String asyncTask() throws InterruptedException {
        long start = System.currentTimeMillis();
        taskService.asyncTask();
        long end = System.currentTimeMillis();
        log.info("time: {}", end - start);
        return "success";
    }
}

请求接口：无等待，直接返回

GET http://localhost:8080/task/asyncTask
Accept: application/json

3、@Async 异步任务-有返回值

异步任务

package com.example.demo.service;
import lombok.extern.slf4j.Slf4j;
import org.springframework.scheduling.annotation.Async;
import org.springframework.scheduling.annotation.AsyncResult;
import org.springframework.stereotype.Service;
import java.util.concurrent.Future;
@Service
@Slf4j
public class TaskService {
   /**
    * 异步任务, 有返回值
    * @throws InterruptedException
    */
   @Async
   public Future<String> asyncTaskFuture() throws InterruptedException {
       Thread.sleep(1000 * 2);
       System.out.println("asyncTaskFuture");
       return new AsyncResult<>("asyncTaskFuture");
   }
}

控制器

package com.example.demo.controller;
import com.example.demo.service.TaskService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
@RestController
@RequestMapping("/task")
@Slf4j
public class TaskController {
    @Autowired
    private TaskService taskService;
    @GetMapping("/asyncTaskFuture")
    public String asyncTaskFuture() throws InterruptedException, ExecutionException {
        long start = System.currentTimeMillis();
        Future<String> future = taskService.asyncTaskFuture();
        // 线程等待结果返回
        String result = future.get();
        long end = System.currentTimeMillis();
        log.info("time: {}", end - start);
        return result;
    }
}

请求接口：等待2秒后返回

GET http://localhost:8080/task/asyncTaskFuture
Accept: application/json

4、@Async + 自定义线程池

package com.example.demo.config;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
import java.util.concurrent.Executor;
import java.util.concurrent.ThreadPoolExecutor;
/**
 * 自定义线程池
 */
@Configuration
public class ExecutorAsyncConfig {
    @Bean(name = "newAsyncExecutor")
    public Executor newAsync() {
        ThreadPoolTaskExecutor taskExecutor = new ThreadPoolTaskExecutor();
        // 设置核心线程数
        taskExecutor.setCorePoolSize(10);
        // 线程池维护线程的最大数量，只有在缓冲队列满了以后才会申请超过核心线程数的线程
        taskExecutor.setMaxPoolSize(100);
        // 缓存队列
        taskExecutor.setQueueCapacity(50);
        // 允许的空闲时间，当超过了核心线程数之外的线程在空闲时间到达之后会被销毁
        taskExecutor.setKeepAliveSeconds(200);
        // 异步方法内部线程名称
        taskExecutor.setThreadNamePrefix("my-xiaoxiao-AsyncExecutor-");
        // 拒绝策略
        taskExecutor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
        taskExecutor.initialize();
        return taskExecutor;
    }
}

异步任务

package com.example.demo.service;
import lombok.extern.slf4j.Slf4j;
import org.springframework.scheduling.annotation.Async;
import org.springframework.scheduling.annotation.AsyncResult;
import org.springframework.stereotype.Service;
import java.util.concurrent.Future;
@Service
@Slf4j
public class TaskService {
   /**
    * 自定义线程池 执行异步任务
    * @throws InterruptedException
    */
   @Async("newAsyncExecutor")
   public void asyncTaskNewAsync() throws InterruptedException {
       Thread.sleep(1000 * 2);
       System.out.println("asyncTaskNewAsync");
   }
}

控制器

package com.example.demo.controller;
import com.example.demo.service.TaskService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
@RestController
@RequestMapping("/task")
@Slf4j
public class TaskController {
    @Autowired
    private TaskService taskService;
    @GetMapping("/asyncTaskNewAsync")
    public String asyncTaskNewAsync() throws InterruptedException {
        long start = System.currentTimeMillis();
        taskService.asyncTaskNewAsync();
        long end = System.currentTimeMillis();
        log.info("time: {}", end - start);
        return "success";
    }
}

请求接口：无等待，直接返回

GET http://localhost:8080/task/asyncTaskNewAsync
Accept: application/json

5、CompletableFuture 实现异步任务

不需要在启动类上加@EnableAsync 注解，也不需要在方法上加@Async 注解

控制器

package com.example.demo.controller;
import com.example.demo.service.TaskService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
@RestController
@RequestMapping("/task")
@Slf4j
public class TaskController {
    @GetMapping("/completableFuture")
    public String completableFuture(){
        long start = System.currentTimeMillis();
        // CompletableFuture实现异步任务
        CompletableFuture<Void> result = CompletableFuture.runAsync(() -> {
            try {
                Thread.sleep(1000 * 2);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println("CompletableFuture");
        });
        long end = System.currentTimeMillis();
        log.info("time: {}", end - start);
        return "success";
    }
}