随着业务倒退，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，这时候接口就须要进行性能优化了，当然性能优化次要跟业务相干波及革新点可能各不相同，这里就来介绍异步调用多个接口缩小响应工夫
实用条件
- 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
优化前调用形式
优化前的代码依照顺序调用形式：
import lombok.extern.slf4j.Slf4j;@Slf4jpublic 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("执行后果：{} 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; } }}执行后果：
21:40:17.603 [main] INFO DemoTest$InterfaceA - 执行接口InterfaceA.process 耗时：2002ms21:40:19.612 [main] INFO DemoTest$InterfaceB - 执行接口InterfaceB.process 耗时：2001ms21:40:19.613 [main] INFO DemoTest - 执行后果：2 耗时：4018优化后调用形式
优化后的代码依照异步调用形式：
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;@Slf4jpublic 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("执行后果：{} 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; } }}执行后果：
22:03:43.180 [线程名称-1] INFO DemoTest$InterfaceB - 执行接口InterfaceB.process 耗时：2004ms22:03:43.180 [线程名称-0] INFO DemoTest$InterfaceA - 执行接口InterfaceA.process 耗时：2004ms22:03:43.190 [main] INFO DemoTest - 执行后果：2 耗时：2020此形式还能够联合CompletionService可实现异步工作和执行后果拆散，大家能够自行搜寻实际
弱小的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;@Slf4jpublic 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("执行异样"); } return dataList; }).exceptionally(e -> Lists.newArrayList()); int result = future.get().get(0) + future.get().get(1); log.info("执行后果：{} 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; } }}执行后果：
22:31:44.822 [ForkJoinPool.commonPool-worker-5] INFO DemoTest$InterfaceB - 执行接口InterfaceB.process 耗时：2005ms22:31:44.822 [ForkJoinPool.commonPool-worker-3] INFO DemoTest$InterfaceA - 执行接口InterfaceA.process 耗时：2002ms22:31:44.831 [main] INFO DemoTest - 执行后果：2 耗时：2027优化时留神点
- 应用线程池避免内存溢出危险
- 执行后果容器可自行依据须要设置
- 接口粒度可依据理论业务状况组合和拆分