Spring Boot使用@Async異步多個結果集合並

以我的搜索功能爲例，多個搜索結果合併

異步類：AsyncService

import java.util.concurrent.Future;

import org.springframework.scheduling.annotation.Async;
import org.springframework.scheduling.annotation.AsyncResult;
import org.springframework.stereotype.Service;

@Service
public class AsyncService {
	/**
	 * 應用搜索-異步
	 */
	@Async
	public Future<String> searchAppInfo() throws Exception{
		//自己的業務邏輯
				
		//睡眠3秒測試		
		Thread.sleep(3000);	
		
		String result = null;
		return new AsyncResult<String>(result);
	}
	
	/**
	 * 待辦搜索-異步
	 */
	@Async
	public Future<String> searchPending() throws Exception{
		//自己的業務邏輯
				
		//睡眠1秒測試		
		Thread.sleep(1000);	
		
		String result = null;
		return new AsyncResult<String>(result);
	}
	
	/**
	 * 用戶搜索-異步
	 */
	@Async
	public Future<String> searchUser() throws Exception{
		//自己的業務邏輯
				
		//睡眠2秒測試		
		Thread.sleep(2000);	
		
		String result = null;
		return new AsyncResult<String>(result);
	}
}

業務類：CompositeService

import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;

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

@Service
public class CompositeService {
	@Autowired
    private AsyncService asyncService;
	
	/**
	 * 綜合搜索集合
	 */
	public Map<String, String> searchList() {
		try {
			long beforeTime = System.currentTimeMillis();// 開始時間戳
			
			//應用搜索-異步
			Future<String> appResult = asyncService.searchAppInfo();
			//待辦搜索-異步
			Future<String> pendingResult = asyncService.searchPending();
			//用戶搜索-異步
			Future<String> userResult = asyncService.searchUser();

			
			//添加結果集，30秒超時
			Map<String, String> jsonObject = new HashMap<String, String>();
			if(appResult != null){
				jsonObject.put("AppInfo", appResult.get(30, TimeUnit.SECONDS));
			}
			if(pendingResult != null){
				jsonObject.put("AppPending", pendingResult.get(30, TimeUnit.SECONDS));
			}
			if(userResult != null){
				jsonObject.put("UnifiedUser", userResult.get(30, TimeUnit.SECONDS));
			}
			
			long afterTime = System.currentTimeMillis();// 結束時間戳
			//耗時3秒多正確，耗時6秒多異步未成功
			System.out.println("耗時"+(afterTime - beforeTime)+"毫秒");
			
			return jsonObject;
		} catch (Exception e) {
			e.printStackTrace();
			return null;
		}	
	}
}

調用測試：ControllerTest

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import com.async.service.CompositeService;

/**
 * 測試異步任務
 */
@RestController
public class ControllerTest {
    @Autowired
    private CompositeService compositeService;
    
    @GetMapping("/test")
    public String test(){
        compositeService.searchList();
        return "異步測試...............";
    }
}

打印結果，應該爲3秒多，因爲休眠的時間最長的一個方法是3秒

耗時3011毫秒

如果有打印出6秒多，證明有問題，實在解決不了的，可以使用笨一點的辦法，修改業務類CompositeService代碼

import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;

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

@Service
public class CompositeService {
	@Autowired
    private AsyncService asyncService;
	
	/**
	 * 綜合搜索集合
	 */
	public Map<String, String> searchList() {
		try {
			long beforeTime = System.currentTimeMillis();// 開始時間戳
			
			//應用搜索-異步
			Future<String> appResult = asyncService.searchAppInfo();
			//待辦搜索-異步
			Future<String> pendingResult = asyncService.searchPending();
			//用戶搜索-異步
			Future<String> userResult = asyncService.searchUser();

			//循環判斷所有異步方法是否執行完畢
			long beforeTime1 = System.currentTimeMillis();// 開始時間戳
			while (true) {
				//執行完畢跳出循環
				if((appResult == null || appResult.isDone()) 
						&& (pendingResult == null || pendingResult.isDone())
						&& (userResult == null || userResult.isDone())){
					break;
				}
				//超時跳出循環
				long afterTime1 = System.currentTimeMillis();// 結束時間戳
				if((afterTime1 - beforeTime1) > 30000){	//30秒
					break;
				}
				Thread.sleep(20);	//每隔20毫秒執行一次
			}
			
			//添加結果集，30秒超時
			Map<String, String> jsonObject = new HashMap<String, String>();
			if(appResult != null){
				jsonObject.put("AppInfo", appResult.get());
			}
			if(pendingResult != null){
				jsonObject.put("AppPending", pendingResult.get());
			}
			if(userResult != null){
				jsonObject.put("UnifiedUser", userResult.get());
			}
			
			long afterTime = System.currentTimeMillis();// 結束時間戳
			//耗時3秒多正確，耗時6秒多異步未成功
			System.out.println("耗時"+(afterTime - beforeTime)+"毫秒");
			
			return jsonObject;
		} catch (Exception e) {
			e.printStackTrace();
			return null;
		}	
	}
}

使用循環判斷Future類自帶的方法isDone()判斷是否執行完畢

//循環判斷所有異步方法是否執行完畢
			long beforeTime1 = System.currentTimeMillis();// 開始時間戳
			while (true) {
				//執行完畢跳出循環
				if((appResult == null || appResult.isDone()) 
						&& (pendingResult == null || pendingResult.isDone())
						&& (userResult == null || userResult.isDone())){
					break;
				}
				//超時跳出循環
				long afterTime1 = System.currentTimeMillis();// 結束時間戳
				if((afterTime1 - beforeTime1) > 30000){	//30秒
					break;
				}
				Thread.sleep(20);	//每隔20毫秒執行一次
			}