springMVC 之异步请求

使用Callable的和流程
1、控制器返回一个Callable。
2、Spring 异步处理，将callable提交到TaskExecutor ，使用一个单独的线程进行处理。
3、DispatcherServlet和所有Filters退出Web容器线程，但response保持打开状态。
4、Callable返回结果，Spring MVC将请求发送回Servlet容器以完成处理。
5、根据callable返回的结果。SpringMVC 继续进行视图渲染等流程（从收到请求-视图渲染）

maven环境

<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.yu</groupId>
  <artifactId>springMVC</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>war</packaging>
    
  <dependencies>
  	<dependency>
	     <groupId>org.springframework</groupId>
	     <artifactId>spring-webmvc</artifactId>
	     <version>4.3.11.RELEASE</version>
     </dependency>
     <dependency>
	    <groupId>javax.servlet</groupId>
	    <artifactId>javax.servlet-api</artifactId>
	    <version>3.1.0</version>
	    <scope>provided</scope>
	</dependency>
	<dependency>
	    <groupId>dom4j</groupId>
	    <artifactId>dom4j</artifactId>
	    <version>1.6.1</version>
	</dependency>
	<dependency>
	    <groupId>jaxen</groupId>
	    <artifactId>jaxen</artifactId>
	    <version>1.1.6</version>
	</dependency>
  </dependencies>
  
   <build>
  	<plugins>
  		<plugin>
  			<groupId>org.apache.maven.plugins</groupId>
			  <artifactId>maven-war-plugin</artifactId>
			  <version>2.4</version>
			  <configuration>
			  	<failOnMissingWebXml>false</failOnMissingWebXml>
			  </configuration>
  		</plugin>
  		<plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.0</version>
                <configuration>
                    <source>1.8</source>    <!-- Java版本号 -->
                    <target>1.8</target>
                </configuration>
            </plugin>
  	</plugins>
  </build> 
</project>

新建一个contourller类

package com.yu.Controller;

import java.util.UUID;
import java.util.concurrent.Callable;
import java.util.concurrent.TimeUnit;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.context.request.async.DeferredResult;

@Controller
public class AsyncController {
     
	
	@ResponseBody
	@RequestMapping("/quo")
	public DeferredResult<Object> quotes11() {
     
		//登待3秒 如果还没有谁调用setResult();这个方法就返回一个eorr
	    DeferredResult<Object> deferredResult = new DeferredResult<Object>((long)3000,"eorr");
	    DeferredResultQueue.save(deferredResult);
	    return deferredResult;
	}
	
	@ResponseBody
	@RequestMapping("/getss")
	public String getss() {
     
		String name = UUID.randomUUID().toString();
		DeferredResult<Object> deferredResult = DeferredResultQueue.get();
		deferredResult.setResult(name);
	    return "success====>"+name;
	}
	
	@ResponseBody
	@RequestMapping("/ns")
	public Callable<String> nsync01() {
     
		System.out.println("主线程开始执行："+Thread.currentThread().getName());
		Callable<String> callable = new Callable<String>(){
     

			@Override
			public String call() throws Exception {
     
				System.out.println("副线程开始执行："+Thread.currentThread().getName());
				TimeUnit.SECONDS.sleep(2L);
				System.out.println("副线程开始执行："+Thread.currentThread().getName());
				return "nsync01......";
			}
			
		};
		System.out.println("主线程执行结束："+Thread.currentThread().getName());
		return callable;

	}
}

定义一个DeferredResultQueue用于保存信息的类

package com.yu.Controller;

import java.util.Queue;
import java.util.concurrent.ConcurrentLinkedQueue;

import org.springframework.web.context.request.async.DeferredResult;

public class DeferredResultQueue {
     
	private static Queue<DeferredResult<Object>>  queue = new ConcurrentLinkedQueue<>();
	
	public static void save(DeferredResult<Object> deferredResult){
     
		queue.add(deferredResult);
	}
	
	public static DeferredResult<Object> get(){
     
		return queue.poll();
	}

}

测试的结果

http://127.0.0.1:8080/springMVC/quo

http://127.0.0.1:8080/springMVC/getss