0.开发环境

• Spring Boot - 2.0.6.RELEASE
• JDK - 1.8 or later
• Spring Framework - 5.0.9 RELEASE
• Maven - 3.2+
• IDE - Eclipse or Spring Tool Suite (STS)

1.maven依赖

    
        
     
      4.0.0
         
     
      net.guides.springboot
         
     
      springboot-async-example
         
     
      0.0.1-SNAPSHOT
         
     
      jar
         
     
      springboot-async-example
         
     
      Demo project for Spring Boot
         
             
      
       org.springframework.boot
              
      
       spring-boot-starter-parent
              
      
       2.0.6.RELEASE
              
              
          
         
             
      
       UTF-8
              
      
       UTF-8
              
      
       1.8
          
         
             
                  
       
        org.springframework.boot
                   
       
        spring-boot-starter-web
               
              
                  
       
        org.springframework.boot
                   
       
        spring-boot-starter-test
                   
       
        test
               
          
         
             
                  
                       
        
         org.springframework.boot
                        
        
         spring-boot-maven-plugin
                    
               
          
     
    

2.首先，我们定义一个用户类

package net.guides.springboot.springbootasyncexample.model;import com.fasterxml.jackson.annotation.JsonIgnoreProperties;@JsonIgnoreProperties(ignoreUnknown = true)public class User {    private String name;    private String blog;    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public String getBlog() {        return blog;    }    public void setBlog(String blog) {        this.blog = blog;    }    @Override    public String toString() {        return "User [name=" + name + ", blog=" + blog + "]";    }}

3.定义一个查询服务

package net.guides.springboot.springbootasyncexample.service;import java.util.concurrent.CompletableFuture;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.boot.web.client.RestTemplateBuilder;import org.springframework.scheduling.annotation.Async;import org.springframework.stereotype.Service;import org.springframework.web.client.RestTemplate;import net.guides.springboot.springbootasyncexample.model.User;@Servicepublic class GitHubLookupService {    private static final Logger logger = LoggerFactory.getLogger(GitHubLookupService.class);    private final RestTemplate restTemplate;    public GitHubLookupService(RestTemplateBuilder restTemplateBuilder) {        this.restTemplate = restTemplateBuilder.build();    }    @Async("threadPoolTaskExecutor")    public CompletableFuture < User > findUser(String user) throws InterruptedException {        logger.info("Looking up " + user);        String url = String.format("https://api.github.com/users/%s", user);        User results = restTemplate.getForObject(url, User.class);        // Artificial delay of 1s for demonstration purposes        Thread.sleep(1000 L);        return CompletableFuture.completedFuture(results);    }}

我们看到，其中的findUser方法需要异步执行，并且该方法还有返回值。

4.配置异步线程池

package net.guides.springboot.springbootasyncexample;import java.util.concurrent.CompletableFuture;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.boot.CommandLineRunner;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.context.annotation.Bean;import org.springframework.core.task.TaskExecutor;import org.springframework.scheduling.annotation.EnableAsync;import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;import net.guides.springboot.springbootasyncexample.model.User;import net.guides.springboot.springbootasyncexample.service.GitHubLookupService;@SpringBootApplication@EnableAsyncpublic class SpringbootAsyncApplication implements CommandLineRunner {    private static final Logger logger = LoggerFactory.getLogger(SpringbootAsyncApplication.class);    @Autowired    private GitHubLookupService gitHubLookupService;    @Bean("threadPoolTaskExecutor")    public TaskExecutor getAsyncExecutor() {        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();        executor.setCorePoolSize(20);        executor.setMaxPoolSize(1000);        executor.setWaitForTasksToCompleteOnShutdown(true);        executor.setThreadNamePrefix("Async-");        return executor;    }    public static void main(String[] args) {        SpringApplication.run(SpringbootAsyncApplication.class, args);    }    @Override    public void run(String...args) throws Exception {        // Start the clock        long start = System.currentTimeMillis();        // Kick of multiple, asynchronous lookups        CompletableFuture < User > page1 = gitHubLookupService.findUser("PivotalSoftware");        CompletableFuture < User > page2 = gitHubLookupService.findUser("CloudFoundry");        CompletableFuture < User > page3 = gitHubLookupService.findUser("Spring-Projects");        CompletableFuture < User > page4 = gitHubLookupService.findUser("RameshMF");        // Wait until they are all done        CompletableFuture.allOf(page1, page2, page3, page4).join();        // Print results, including elapsed time        logger.info("Elapsed time: " + (System.currentTimeMillis() - start));        logger.info("--> " + page1.get());        logger.info("--> " + page2.get());        logger.info("--> " + page3.get());        logger.info("--> " + page4.get());    }}

全文来自：[Spring Boot: Creating Asynchronous Methods Using Annotation]()