springmvc异步处理请求

有两种情况，第一种是业务逻辑复杂，但不需要业务逻辑的结果，第二种是需要返回业务逻辑的处理结果

第一种比较简单，利用多线程处理业务逻辑，或者利用spring中@Asyn注解更简单，

使用@Asyn注解，要首先要配置开启异步注解

   
   
@Configuration
@EnableAsync
public class AsyncConfig {

}
  
  

然后直接在方法上注解即可

   
   
@Service
public class AsyncAction {

@Async
public void fun1() {
try {
Thread.sleep( 10000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println( "fun1");
}
}
  
  

切记异步类的bean不能被重复扫描，而且只能被sping容器的上下文扫描，不能被spingmvc扫描，否则异步失效

第二种需要返回业务逻辑情况则首先需要开启异步支持

   
   
public class SpitterWebInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
@Override
protected void customizeRegistration(Dynamic registration) {
registration.setAsyncSupported( true);
}
  
  

或者在web.xml中开启

   
   
<servlet>
<servlet-name>SpringMvc </servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet </servlet-class>
<init-param>
<param-name>contextConfigLocation </param-name>
<param-value>... </param-value>
</init-param>
<load-on-startup>1 </load-on-startup>
<async-supported>true </async-supported>
</servlet>
  
  

然后配置一下线程池

   
   
@Configuration
@EnableWebMvc
@ComponentScan( "spittr.web")
public class WebConfig extends WebMvcConfigurerAdapter {

@Override
public void configureAsyncSupport(AsyncSupportConfigurer configurer) {
ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
executor.setCorePoolSize( 5);
executor.setMaxPoolSize( 10);
executor.setQueueCapacity( 50);
executor.setThreadNamePrefix( "abc-");
executor.setKeepAliveSeconds( 30);
configurer.setTaskExecutor(executor);
configurer.setDefaultTimeout( 600);
}
  
  

   
   
@Configuration
@EnableWebMvc
@ComponentScan( "spittr.web")
public class WebConfig extends WebMvcConfigurerAdapter {
  
  

这样就可以开始异步处理任务了，能够尽快释放servlet线程，缓解高并发问题

   
   
@RequestMapping(value = "/async")

public @ResponseBody Callable<String> async() {
  
  

 return new Callable<String>() {
            @Override
            public String call() throws Exception {
                Thread.sleep(2000);
                return "Callable result";
            }
        };

}