CompletableFuture實現異步回調

import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;

public class CompletableFutureDemo {
    public static void main(String[] args) throws ExecutionException, InterruptedException {
//        CompletableFuture<Void> voidCompletableFuture = CompletableFuture.runAsync(() -> {
//            System.out.println("CompletableFuture 的沒有返回參數");
//        });
//        voidCompletableFuture.get();

        CompletableFuture<String> supplyAsync = CompletableFuture.supplyAsync(() -> {
//            System.out.println("CompletableFuture 的 supplyAsync 有參數返回");//處理邏輯
            int a = 10/0;
            return "1024";
        });
        String s = supplyAsync.whenComplete((u, t) -> {
            System.out.println("u:" + u);
            System.out.println("t:" + t);
        }).exceptionally(e -> {
//            System.out.println(e.getMessage());
            return e.getMessage();
        }).get();

//        System.out.println(s);
    }
}

 int a = 10/0;是爲了提供異常處理

whenComplete的兩個參數第一個是接受的返回值，t是異常信息

整個代碼風格使用的鏈式編程風格