Java：SpringBoot @Async实现异步任务

目录

• • 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

<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/> </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;@SpringBootApplicationpublic 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@Slf4jpublic 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")@Slf4jpublic 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/syncTaskAccept: 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@EnableAsyncpublic 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@Slf4jpublic 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")@Slf4jpublic 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/asyncTaskAccept: 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@Slf4jpublic 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")@Slf4jpublic 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/asyncTaskFutureAccept: 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 */@Configurationpublic 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@Slf4jpublic 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")@Slf4jpublic 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/asyncTaskNewAsyncAccept: 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")@Slf4jpublic 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";    }}

参考
SpringBoot使用@Async的总结！