Spring boot 实现高吞吐量异步处理（适用于高并发场景）

技术要点

org.springframework.web.context.request.async.DeferredResult<T>

示例如下：

1.   新建Maven项目  async

2.   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
        http://maven.apache.org/xsd/maven-4.0.0.xsd">

    <modelVersion>4.0.0</modelVersion>
    <groupId>com.java</groupId>
    <artifactId>async</artifactId>
    <version>1.0.0</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.5.RELEASE</version>
    </parent>

    <dependencies>

        <!-- Spring Boot -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!-- 热部署 -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>springloaded</artifactId>
            <version>1.2.8.RELEASE</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>provided</scope>
        </dependency>

    </dependencies>

    <build>
        <finalName>${project.artifactId}</finalName>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>

            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <executions>
                    <execution>
                        <goals>
                            <goal>repackage</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

3.   AsyncStarter.java

package com.java;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class AsyncStarter {

    public static void main(String[] args) {
        SpringApplication.run(AsyncStarter.class, args);
    }

}

4.   AsyncVo.java

package com.java.vo;

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

/**
 * 存储异步处理信息
 *
 * @author Logen
 *
 * @param <I> 接口输入参数
 * @param <O> 接口返回参数
 */
public class AsyncVo<I, O> {

    /**
     * 请求参数
     */
    private I params;

    /**
     * 响应结果
     */
    private DeferredResult<O> result;

    public I getParams() {
        return params;
    }

    public void setParams(I params) {
        this.params = params;
    }

    public DeferredResult<O> getResult() {
        return result;
    }

    public void setResult(DeferredResult<O> result) {
        this.result = result;
    }

}

5.   RequestQueue.java

package com.java.queue;

import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingQueue;

import org.springframework.stereotype.Component;

import com.java.vo.AsyncVo;

/**
 * 存放所有异步处理接口请求队列的对象,一个接口对应一个队列
 *
 * @author Logen
 *
 */
@Component
public class RequestQueue {

    /**
     * 处理下订单接口的队列，设置缓冲容量为50
     */
    private BlockingQueue<AsyncVo<String, Object>> orderQueue = new LinkedBlockingQueue<>(50);

    public BlockingQueue<AsyncVo<String, Object>> getOrderQueue() {
        return orderQueue;
    }

}

6.   OrderTask.java

package com.java.task;

import java.util.HashMap;
import java.util.Map;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

import com.java.queue.RequestQueue;
import com.java.vo.AsyncVo;

/**
 * 处理订单接口的任务，每个任务类处理一种接口
 *
 * @author Logen
 *
 */
@Component
public class OrderTask extends Thread {

    @Autowired
    private RequestQueue queue;

    private boolean running = true;

    @Override
    public void run() {
        while (running) {
            try {
                AsyncVo<String, Object> vo = queue.getOrderQueue().take();
                System.out.println("[ OrderTask ]开始处理订单");

                String params = vo.getParams();
                Thread.sleep(3000);
                Map<String, Object> map = new HashMap<>();
                map.put("params", params);
                map.put("time", System.currentTimeMillis());

                vo.getResult().setResult(map);

                System.out.println("[ OrderTask ]订单处理完成");
            } catch (InterruptedException e) {
                e.printStackTrace();
                running = false;
            }

        }
    }

    public void setRunning(boolean running) {
        this.running = running;
    }

}

7.   QueueListener.java

package com.java.listener;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

import com.java.task.OrderTask;

/**
 * 队列监听器，初始化启动所有监听任务
 *
 * @author Logen
 *
 */
@Component
public class QueueListener {

    @Autowired
    private OrderTask orderTask;

    /**
     * 初始化时启动监听请求队列
     */
    @PostConstruct
    public void init() {
        orderTask.start();
    }

    /**
     * 销毁容器时停止监听任务
     */
    @PreDestroy
    public void destory() {
        orderTask.setRunning(false);
    }

}

8.   OrderController.java

package com.java.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.context.request.async.DeferredResult;

import com.java.queue.RequestQueue;
import com.java.vo.AsyncVo;

/**
 * <blockquote>
 *
 * <pre>
 *
 * 模拟下单处理，实现高吞吐量异步处理请求
 *
 * 1、 Controller层接口只接收请求，不进行处理，而是把请求信息放入到对应该接口的请求队列中
 * 2、 该接口对应的任务类监听对应接口的请求队列，从队列中顺序取出请求信息并进行处理
 *
 * 优点：接口几乎在收到请求的同时就已经返回，处理程序在后台异步进行处理，大大提高吞吐量
 *
 *
 * </pre>
 *
 * </blockquote>
 *
 * @author Logen
 *
 */
@RestController
public class OrderController {

    @Autowired
    private RequestQueue queue;

    @GetMapping("/order")
    public DeferredResult<Object> order(String number) throws InterruptedException {
        System.out.println("[ OrderController ] 接到下单请求");
        System.out.println("当前待处理订单数： " + queue.getOrderQueue().size());

        AsyncVo<String, Object> vo = new AsyncVo<>();
        DeferredResult<Object> result = new DeferredResult<>();

        vo.setParams(number);
        vo.setResult(result);

        queue.getOrderQueue().put(vo);
        System.out.println("[ OrderController ] 返回下单结果");
        return result;
    }

}

9.   运行 AsyncStarter.java ，启动测试

浏览器输入 http://localhost:8080/order?number=10001

正常情况处理3秒返回，返回结果如下

{"time":1548241500718,"params":"10001"}

观察控制台打印日志，如下所示：

[ OrderController ] 接到下单请求
当前待处理订单数： 0
[ OrderController ] 返回下单结果
[ OrderTask ]开始处理订单
[ OrderTask ]订单处理完成

结论：Controller层几乎在接收到请求的同时就已经返回，处理程序在后台异步处理任务。

快速多次刷新浏览器，目的为了高并发测试，观察控制台打印信息

现象：Controller层快速返回，待处理请求在队列中开始增加，异步处理程序在按顺序处理请求。

优点：对客户端响应时间不变，但提高了服务端的吞吐量。大大提升高并发处理性能！

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