@Async 메서드 사용 예시 작성

.gitignore

@@ -1,6 +1,6 @@
 HELP.md
-.gradle
-build/
+.gradle/*
+build/*
 !gradle/wrapper/gradle-wrapper.jar
 !**/src/main/**/build/
 !**/src/test/**/build/
@@ -18,7 +18,7 @@ bin/
 !**/src/test/**/bin/
 
 ### IntelliJ IDEA ###
-.idea
+.idea/*
 *.iws
 *.iml
 *.ipr

src/main/java/com/thread/concurrency/SpringThreadConcurrencyApplication.java

@@ -2,12 +2,27 @@
 
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.Bean;
+import org.springframework.scheduling.annotation.EnableAsync;
+import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
+
+import java.util.concurrent.Executor;
 
 @SpringBootApplication
+@EnableAsync
 public class SpringThreadConcurrencyApplication {
 
     public static void main(String[] args) {
         SpringApplication.run(SpringThreadConcurrencyApplication.class, args);
     }
-
+    @Bean
+    public Executor taskExecutor() {
+        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor(); // Spring에서 사용하는 스레드를 제어한느 설정
+        executor.setCorePoolSize(50); // thread-pool에 살아있는 thread의 최소 개수
+        executor.setMaxPoolSize(50);  // thread-pool에서 사용할 수 있는 최대 개수
+        executor.setQueueCapacity(500); //thread-pool에 최대 queue 크기
+        executor.setThreadNamePrefix("AsyncApp-");
+        executor.initialize();
+        return executor;
+    }
 }

src/main/java/com/thread/concurrency/async/controller/AsyncController.java

@@ -0,0 +1,35 @@
+package com.thread.concurrency.async.controller;
+
+import com.thread.concurrency.async.service.AsyncService;
+import org.springframework.scheduling.annotation.Async;
+import org.springframework.stereotype.Controller;
+
+import java.time.Duration;
+import java.time.LocalTime;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.CompletableFuture;
+
+@Controller
+public class AsyncController {
+    private final AsyncService asyncService;
+
+    public AsyncController(AsyncService asyncService) {
+        this.asyncService = asyncService;
+    }
+
+    @Async
+    public CompletableFuture<String> calculateRunTime(int cnt, int waitTime) throws InterruptedException {
+        LocalTime lt1 = LocalTime.now();
+        List<CompletableFuture<String>> hellos = new ArrayList<>();
+        for(int i=0; i<cnt; i++){
+            hellos.add(asyncService.voidParamStringReturn(waitTime,i+"번째 메세지"));
+        }
+        // 모든 비동기 호출이 완료될 때까지 대기하고 결과를 리스트에 넣기
+        List<String> results = hellos.stream().map(CompletableFuture::join)
+            .toList();
+        LocalTime lt2 = LocalTime.now();
+        long dif = Duration.between(lt1, lt2).toMillis();
+        return CompletableFuture.completedFuture(dif+"가 걸렸습니다.");
+    }
+}

src/main/java/com/thread/concurrency/async/service/AsyncService.java

@@ -0,0 +1,18 @@
+package com.thread.concurrency.async.service;
+
+import org.springframework.scheduling.annotation.Async;
+import org.springframework.stereotype.Service;
+
+import java.util.concurrent.CompletableFuture;
+
+
+@Service
+public class AsyncService {
+    @Async
+    public CompletableFuture<String> voidParamStringReturn (long waitTime, String message) throws InterruptedException{
+        System.out.println("비동기적으로 실행 - "+
+            Thread.currentThread().getName());
+        Thread.sleep(waitTime);
+        return CompletableFuture.completedFuture(message);
+    }
+}

src/test/java/com/thread/concurrency/AsyncControllerTest.java

@@ -0,0 +1,32 @@
+package com.thread.concurrency;
+
+import com.thread.concurrency.async.controller.AsyncController;
+import org.junit.jupiter.api.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.CompletableFuture;
+
+@SpringBootTest
+public class AsyncControllerTest {
+    private static final Logger logger = LoggerFactory.getLogger(AsyncServiceTest.class);
+
+    @Autowired
+    private AsyncController asyncController;
+
+    @Test
+    public void invokeMultiAsyncMethod() throws InterruptedException {
+        List<CompletableFuture<String>> hellos = new ArrayList<>();
+        for(int i=0; i<10; i++){
+            hellos.add(asyncController.calculateRunTime(10, 1000));
+        }
+        // 모든 비동기 호출이 완료될 때까지 대기하고 결과를 리스트에 넣기
+        List<String> results = hellos.stream().map(CompletableFuture::join)
+            .toList();
+        results.forEach(logger::info);
+    }
+}

src/test/java/com/thread/concurrency/AsyncServiceTest.java

@@ -0,0 +1,52 @@
+package com.thread.concurrency;
+
+import com.thread.concurrency.async.service.AsyncService;
+import org.junit.jupiter.api.*;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
+
+@SpringBootTest
+public class AsyncServiceTest {
+    private static final Logger logger = LoggerFactory.getLogger(AsyncServiceTest.class);
+    @Autowired
+    private AsyncService asyncService;
+
+    @Test
+    @DisplayName("입력은 void 출력은 String인 비동기 함수 단일 호출")
+    public void testGetString() throws ExecutionException, InterruptedException {
+        CompletableFuture<String> helloWorld = asyncService.voidParamStringReturn(1000,  "기본 메세지");
+        Assertions.assertEquals("기본 메세지",helloWorld.get());
+    }
+
+    @Test
+    @DisplayName("입력은 void 출력은 String인 비동기 함수 다중 호출")
+    public void testGetMultiString() throws InterruptedException {
+        List<CompletableFuture<String>> hellos = new ArrayList<>();
+        for(int i=0; i<100; i++){
+            hellos.add(asyncService.voidParamStringReturn(1000,i+"번째 메세지"));
+        }
+        // 모든 비동기 호출이 완료될 때까지 대기하고 결과를 리스트에 넣기
+        List<String> results = hellos.stream().map(CompletableFuture::join)
+                .toList();
+        results.forEach(logger::info);
+    }
+
+    @Test
+    @DisplayName("입력은 void 출력은 String인 비동기 함수 단일 호출 타임아웃 발생.")
+    public void testGetStringTimeOutIsThisAsync() throws InterruptedException {
+        // voidParamStringReturn가 비동기 메서드인지 의문이 생김.
+        CompletableFuture<String> completableFuture = asyncService.voidParamStringReturn(4000, "타임아웃 발생 안 함!");
+        long timeOutValue = 1;
+        TimeUnit timeUnit = TimeUnit.SECONDS;
+        // 1초가 지난 후 타임아웃 발생
+        Assertions.assertThrows(ExecutionException.class, () -> completableFuture.orTimeout(timeOutValue,timeUnit).get());
+    }
+}