直播系统开发，接口异步调用一小步，耗时减少一大步

随着直播系统开发业务发展，底层数据量越来越大，业务逻辑也日趋复杂化，某些接口耗时也越来越长，这时候接口就需要进行性能优化了，当然性能优化主要跟业务相关涉及改造点可能各不相同，这里就来介绍异步调用多个接口减少响应时间。

适用条件

调用多个独立的接口，接口间无相互依赖关系
非耗时最大的接口占总耗时比重较大

优化前调用方式

优化前的代码按照顺序调用方式：

import lombok.extern.slf4j.Slf4j;

@Slf4j
public class DemoTest {

    public static void main(String[] args) throws Exception {
        long beginTime = System.currentTimeMillis();
        int processA = new InterfaceA().process();
        int processB = new InterfaceB().process();
        int result = processA + processB;
        log.info("执行结果：{} 耗时：{}", result, System.currentTimeMillis() - beginTime);
    }

    @Slf4j
    public final static class InterfaceA {
        Integer result = 1;

        public int process() {
            long beginTime = System.currentTimeMillis();
            try {
                Thread.sleep(2000);
            } catch (Exception e) {
                log.error("InterfaceA.process Exception");
            }
            log.info("执行接口InterfaceA.process 耗时：{}ms", System.currentTimeMillis() - beginTime);
            return result;
        }
    }

    @Slf4j
    public final static class InterfaceB {
        Integer result = 1;

        public int process() {
            long beginTime = System.currentTimeMillis();
            try {
                Thread.sleep(2000);
            } catch (Exception e) {
                log.error("InterfaceB.process Exception");
            }
            log.info("执行接口InterfaceB.process 耗时：{}ms", System.currentTimeMillis() - beginTime);
            return result;
        }
    }
}

执行结果：

21:40:17.603 [main] INFO DemoTest$InterfaceA - 执行接口InterfaceA.process 耗时：2002ms
21:40:19.612 [main] INFO DemoTest$InterfaceB - 执行接口InterfaceB.process 耗时：2001ms
21:40:19.613 [main] INFO DemoTest - 执行结果：2 耗时：4018

优化后调用方式

优化后的代码按照异步调用方式：

import cn.hutool.core.thread.ThreadFactoryBuilder;
import lombok.extern.slf4j.Slf4j;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.Future;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

@Slf4j
public class DemoTest {
    private static ThreadPoolExecutor pool = new ThreadPoolExecutor(
            5,
            5,
            60,
            TimeUnit.SECONDS,
            new ArrayBlockingQueue<Runnable>(1000),
            ThreadFactoryBuilder.create().setNamePrefix("线程名称-").build()
    );

    public static void main(String[] args) throws Exception {
        long beginTime = System.currentTimeMillis();

        List<Future<Integer>> futures = new ArrayList<>(2);
        List<Integer> results = new ArrayList<>(2);
        futures.add(pool.submit(() -> new InterfaceA().process()));
        futures.add(pool.submit(() -> new InterfaceB().process()));
        for (Future<Integer> item : futures) {
            results.add(item.get());
        }
        
        int result = results.get(0) + results.get(1);
        log.info("执行结果：{} 耗时：{}", result, System.currentTimeMillis() - beginTime);
    }

    @Slf4j
    public final static class InterfaceA {
        Integer result = 1;

        public int process() {
            long beginTime = System.currentTimeMillis();
            try {
                Thread.sleep(2000);
            } catch (Exception e) {
                log.error("InterfaceA.process Exception");
            }
            log.info("执行接口InterfaceA.process 耗时：{}ms", System.currentTimeMillis() - beginTime);
            return result;
        }
    }

    @Slf4j
    public final static class InterfaceB {
        Integer result = 1;

        public int process() {
            long beginTime = System.currentTimeMillis();
            try {
                Thread.sleep(2000);
            } catch (Exception e) {
                log.error("InterfaceB.process Exception");
            }
            log.info("执行接口InterfaceB.process 耗时：{}ms", System.currentTimeMillis() - beginTime);
            return result;
        }
    }
}

执行结果：

22:03:43.180 [线程名称-1] INFO DemoTest$InterfaceB - 执行接口InterfaceB.process 耗时：2004ms
22:03:43.180 [线程名称-0] INFO DemoTest$InterfaceA - 执行接口InterfaceA.process 耗时：2004ms
22:03:43.190 [main] INFO DemoTest - 执行结果：2 耗时：2020

此方式还可以结合CompletionService可实现异步任务和执行结果分离，大家可以自行搜索实践

强大的CompletableFuture JDK1.8

import com.google.common.collect.Lists;
import lombok.extern.slf4j.Slf4j;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.CompletableFuture;

@Slf4j
public class DemoTest {

    public static void main(String[] args) throws Exception {
        long beginTime = System.currentTimeMillis();

        CompletableFuture<Integer> interfaceFuturesA = CompletableFuture.supplyAsync(() -> new InterfaceA().process());
        CompletableFuture<Integer> interfaceFuturesB = CompletableFuture.supplyAsync(() -> new InterfaceB().process());
        CompletableFuture<List<Integer>> future = CompletableFuture
                .allOf(interfaceFuturesA, interfaceFuturesB)
                .thenApply((none) -> {
                    List<Integer> dataList = new ArrayList<>(2);
                    try {
                        dataList.add(interfaceFuturesA.get());
                        dataList.add(interfaceFuturesB.get());
                    } catch (Exception e) {
                        log.error("执行异常");
                    }
                    return dataList;
                }).exceptionally(e -> Lists.newArrayList());

        int result = future.get().get(0) + future.get().get(1);
        log.info("执行结果：{} 耗时：{}", result, System.currentTimeMillis() - beginTime);
    }

    @Slf4j
    public final static class InterfaceA {
        Integer result = 1;

        public int process() {
            long beginTime = System.currentTimeMillis();
            try {
                Thread.sleep(2000);
            } catch (Exception e) {
                log.error("InterfaceA.process Exception");
            }
            log.info("执行接口InterfaceA.process 耗时：{}ms", System.currentTimeMillis() - beginTime);
            return result;
        }
    }

    @Slf4j
    public final static class InterfaceB {
        Integer result = 1;

        public int process() {
            long beginTime = System.currentTimeMillis();
            try {
                Thread.sleep(2000);
            } catch (Exception e) {
                log.error("InterfaceB.process Exception");
            }
            log.info("执行接口InterfaceB.process 耗时：{}ms", System.currentTimeMillis() - beginTime);
            return result;
        }
    }
}

执行结果：

22:31:44.822 [ForkJoinPool.commonPool-worker-5] INFO DemoTest$InterfaceB - 执行接口InterfaceB.process 耗时：2005ms
22:31:44.822 [ForkJoinPool.commonPool-worker-3] INFO DemoTest$InterfaceA - 执行接口InterfaceA.process 耗时：2002ms
22:31:44.831 [main] INFO DemoTest - 执行结果：2 耗时：2027