多个泛型CompletableFuture获取结果

迷南。 2023-02-12 15:28 8阅读 0赞

获取feed列表通常里边需要依据Id查询用户信息

import java.util.HashMap;
    import java.util.Map;
    import java.util.concurrent.CompletableFuture;
    import java.util.concurrent.ExecutionException;
    import java.util.concurrent.atomic.AtomicLong;
    
    public class BatchCompletableFutureTest {
    
        private static AtomicLong  sample= new AtomicLong(0);
    
        public static void main(String[] args) throws ExecutionException, InterruptedException {
            System.out.println(batchGetFutute().get());
        }
    
        private static CompletableFuture<Map<String,String>>  batchGetFutute(){
            Map<String,CompletableFuture<Map<String,String>>> batchFutureMap = new HashMap<>();
            for (int i=1; i<=10;i++){
                CompletableFuture<Map<String,String>> mapFuture = getMapFuture();
                batchFutureMap.put(String.valueOf(i),mapFuture);
            }
    
            CompletableFuture<Map<String,String>>[] batchFutureMapArray =  new CompletableFuture[batchFutureMap.size()];
            batchFutureMap.values().toArray(batchFutureMapArray);
            
            return CompletableFuture.allOf(batchFutureMapArray).thenApply(x ->{
                Map<String,String> ret = new HashMap<>();
                for (int i=0; i<batchFutureMapArray.length;i++){
                    ret.putAll(batchFutureMapArray[i].join());
                }
                return ret;
            });
        }
    
        private static CompletableFuture<Map<String,String>> getMapFuture(){
            return CompletableFuture.supplyAsync(() ->{
                Map<String,String> ret = new HashMap<>();
                ret.put("k_"+String.valueOf(sample.getAndIncrement()),String.valueOf(System.currentTimeMillis()));
                return ret;
            });
        }
    }

结果

{k_5=1590482981704, k_4=1590482981659, k_7=1590482981668, k_6=1590482981668, k_9=1590482981668, k_8=1590482981668, k_1=1590482981658, k_0=1590482981658, k_3=1590482981658, k_2=1590482981658}