Repository navigation
Expand file tree
/
Copy pathcompletablefuture.html
More file actions
2158 lines (1766 loc) · 78.4 KB
/
Copy pathcompletablefuture.html
File metadata and controls
2158 lines (1766 loc) · 78.4 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
<!DOCTYPE HTML>
<html lang="zh-CN">
<head><meta name="generator" content="Hexo 3.9.0">
<meta charset="utf-8">
<meta name="keywords" content="CompletableFuture 异步编程, 记录">
<meta name="baidu-site-verification" content="fmlEuI34ir">
<meta name="google-site-verification" content="yCy2azpds5XSuGZvis6OuA-XIGF5GuGpYRAaGfD6o48">
<meta name="360-site-verification" content="b7c11a830ef90fd1464ad6206bb7b6e7">
<meta name="description" content="创建异步任务CompletableFuture创建异步任务，一般有supplyAsync和runAsync两个方法
supplyAsync执行CompletableFuture任务，支持返回值
runAsync执行CompletableF">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no">
<meta name="renderer" content="webkit|ie-stand|ie-comp">
<meta name="mobile-web-app-capable" content="yes">
<meta name="format-detection" content="telephone=no">
<meta name="apple-mobile-web-app-capable" content="yes">
<meta name="apple-mobile-web-app-status-bar-style" content="black-translucent">
<title>CompletableFuture 异步编程 | Ji`s Blog</title>
<link rel="icon" type="image/png" href="/favicon.png">
<link rel="stylesheet" type="text/css" href="/libs/awesome/css/font-awesome.min.css">
<link rel="stylesheet" type="text/css" href="/libs/materialize/materialize.min.css">
<link rel="stylesheet" type="text/css" href="/libs/aos/aos.css">
<link rel="stylesheet" type="text/css" href="/libs/animate/animate.min.css">
<link rel="stylesheet" type="text/css" href="/libs/lightGallery/css/lightgallery.min.css">
<link rel="stylesheet" type="text/css" href="/css/matery.css">
<link rel="stylesheet" type="text/css" href="/css/my.css">
<style type="text/css">
</style>
<script src="/libs/jquery/jquery-2.2.0.min.js"></script>
<script src="https://sdk.jinrishici.com/v2/browser/jinrishici.js" charset="utf-8"></script>
<script>
var _hmt = _hmt || [];
(function() {
var hm = document.createElement("script");
hm.src = "https://hm.baidu.com/hm.js?4d1d73af45a62734730491a6b6c41da4";
var s = document.getElementsByTagName("script")[0];
s.parentNode.insertBefore(hm, s);
})();
</script>
<script>(function (i, s, o, g, r, a, m) {
i['DaoVoiceObject'] = r;
i[r] = i[r] ||
function () {
(i[r].q = i[r].q || []).push(arguments);
};
i[r].l = 1 * new Date();
a = s.createElement(o);
m = s.getElementsByTagName(o)[0];
a.async = 1;
a.src = g;
a.charset = 'utf-8';
m.parentNode.insertBefore(a, m);
})(window, document, 'script', ('https:' === document.location.protocol ? 'https:' : 'http:') + "//widget.daovoice.io/widget/xxx.js", 'daovoice');
daovoice('init', {
app_id: "xxx",
});
daovoice('update');
</script>
<script>
(function(){
var bp = document.createElement('script');
var curProtocol = window.location.protocol.split(':')[0];
if (curProtocol === 'https') {
bp.src = 'https://zz.bdstatic.com/linksubmit/push.js';
}
else {
bp.src = 'http://push.zhanzhang.baidu.com/push.js';
}
var s = document.getElementsByTagName("script")[0];
s.parentNode.insertBefore(bp, s);
})();
</script>
<script>
(function(){
var src = "https://jspassport.ssl.qhimg.com/11.0.1.js?d182b3f28525f2db83acfaaf6e696dba";
document.write('<script src="' + src + '" id="sozz"><\/script>');
})();
</script>
<meta name="baidu-site-verification" content>
<style type="text/css" lang="css">
#loading-container{
position: fixed;
top: 0;
left: 0;
min-height: 100vh;
width: 100vw;
z-index: 9999;
display: flex;
flex-direction: column;
justify-content: center;
align-items: center;
background: #FFF;
text-align: center;
/* loaderҳ����ʧ���ý����ķ�ʽ*/
-webkit-transition: opacity 1s ease;
-moz-transition: opacity 1s ease;
-o-transition: opacity 1s ease;
transition: opacity 1s ease;
}
.loading-image{
width: 120px;
height: 50px;
transform: translate(-50%);
}
.loading-image div:nth-child(2) {
-webkit-animation: pacman-balls 1s linear 0s infinite;
animation: pacman-balls 1s linear 0s infinite
}
.loading-image div:nth-child(3) {
-webkit-animation: pacman-balls 1s linear .33s infinite;
animation: pacman-balls 1s linear .33s infinite
}
.loading-image div:nth-child(4) {
-webkit-animation: pacman-balls 1s linear .66s infinite;
animation: pacman-balls 1s linear .66s infinite
}
.loading-image div:nth-child(5) {
-webkit-animation: pacman-balls 1s linear .99s infinite;
animation: pacman-balls 1s linear .99s infinite
}
.loading-image div:first-of-type {
width: 0;
height: 0;
border: 25px solid #49b1f5;
border-right-color: transparent;
border-radius: 25px;
-webkit-animation: rotate_pacman_half_up .5s 0s infinite;
animation: rotate_pacman_half_up .5s 0s infinite;
}
.loading-image div:nth-child(2) {
width: 0;
height: 0;
border: 25px solid #49b1f5;
border-right-color: transparent;
border-radius: 25px;
-webkit-animation: rotate_pacman_half_down .5s 0s infinite;
animation: rotate_pacman_half_down .5s 0s infinite;
margin-top: -50px;
}
@-webkit-keyframes rotate_pacman_half_up {0% {transform: rotate(270deg)}50% {transform: rotate(1turn)}to {transform: rotate(270deg)}}
@keyframes rotate_pacman_half_up {0% {transform: rotate(270deg)}50% {transform: rotate(1turn)}to {transform: rotate(270deg)}}
@-webkit-keyframes rotate_pacman_half_down {0% {transform: rotate(90deg)}50% {transform: rotate(0deg)}to {transform: rotate(90deg)}}
@keyframes rotate_pacman_half_down {0% {transform: rotate(90deg)}50% {transform: rotate(0deg)}to {transform: rotate(90deg)}}
@-webkit-keyframes pacman-balls {75% {opacity: .7}to {transform: translate(-100px, -6.25px)}}
@keyframes pacman-balls {75% {opacity: .7}to {transform: translate(-100px, -6.25px)}}
.loading-image div:nth-child(3),
.loading-image div:nth-child(4),
.loading-image div:nth-child(5),
.loading-image div:nth-child(6){
background-color: #49b1f5;
width: 15px;
height: 15px;
border-radius: 100%;
margin: 2px;
width: 10px;
height: 10px;
position: absolute;
transform: translateY(-6.25px);
top: 25px;
left: 100px;
}
.loading-text{
margin-bottom: 20vh;
text-align: center;
color: #2c3e50;
font-size: 2rem;
box-sizing: border-box;
padding: 0 10px;
text-shadow: 0 2px 10px rgba(0,0,0,0.2);
}
@media only screen and (max-width: 500px) {
.loading-text{
font-size: 1.5rem;
}
}
.fadeout {
opacity: 0;
filter: alpha(opacity=0);
}
/* logo���ֶ��� */
@-webkit-keyframes fadeInDown{0%{opacity:0;-webkit-transform:translate3d(0,-100%,0);transform:translate3d(0,-100%,0)}100%{opacity:1;-webkit-transform:none;transform:none}}
@keyframes fadeInDown{0%{opacity:0;-webkit-transform:translate3d(0,-100%,0);}}
</style>
<script>
(function () {
const loaded = function(){
setTimeout(function(){
const loader = document.getElementById("loading-container");
loader.className="fadeout" ;//ʹ�ý����ķ�������loading page
// document.getElementById("body-wrap").style.display="flex";
setTimeout(function(){
loader.style.display="none";
},1000);
},1000);//ǿ����ʾloading page 1s
};
loaded();
})()
</script><link rel="stylesheet" href="/css/prism-tomorrow.css" type="text/css">
<link rel="stylesheet" href="/css/prism-line-numbers.css" type="text/css"><style type="text/css" lang="css">
#loading-container{
position: fixed;
top: 0;
left: 0;
min-height: 100vh;
width: 100vw;
z-index: 9999;
display: flex;
flex-direction: column;
justify-content: center;
align-items: center;
background: #FFF;
text-align: center;
/* loaderҳ����ʧ���ý����ķ�ʽ*/
-webkit-transition: opacity 1s ease;
-moz-transition: opacity 1s ease;
-o-transition: opacity 1s ease;
transition: opacity 1s ease;
}
.loading-image{
width: 120px;
height: 50px;
transform: translate(-50%);
}
.loading-image div:nth-child(2) {
-webkit-animation: pacman-balls 1s linear 0s infinite;
animation: pacman-balls 1s linear 0s infinite
}
.loading-image div:nth-child(3) {
-webkit-animation: pacman-balls 1s linear .33s infinite;
animation: pacman-balls 1s linear .33s infinite
}
.loading-image div:nth-child(4) {
-webkit-animation: pacman-balls 1s linear .66s infinite;
animation: pacman-balls 1s linear .66s infinite
}
.loading-image div:nth-child(5) {
-webkit-animation: pacman-balls 1s linear .99s infinite;
animation: pacman-balls 1s linear .99s infinite
}
.loading-image div:first-of-type {
width: 0;
height: 0;
border: 25px solid #49b1f5;
border-right-color: transparent;
border-radius: 25px;
-webkit-animation: rotate_pacman_half_up .5s 0s infinite;
animation: rotate_pacman_half_up .5s 0s infinite;
}
.loading-image div:nth-child(2) {
width: 0;
height: 0;
border: 25px solid #49b1f5;
border-right-color: transparent;
border-radius: 25px;
-webkit-animation: rotate_pacman_half_down .5s 0s infinite;
animation: rotate_pacman_half_down .5s 0s infinite;
margin-top: -50px;
}
@-webkit-keyframes rotate_pacman_half_up {0% {transform: rotate(270deg)}50% {transform: rotate(1turn)}to {transform: rotate(270deg)}}
@keyframes rotate_pacman_half_up {0% {transform: rotate(270deg)}50% {transform: rotate(1turn)}to {transform: rotate(270deg)}}
@-webkit-keyframes rotate_pacman_half_down {0% {transform: rotate(90deg)}50% {transform: rotate(0deg)}to {transform: rotate(90deg)}}
@keyframes rotate_pacman_half_down {0% {transform: rotate(90deg)}50% {transform: rotate(0deg)}to {transform: rotate(90deg)}}
@-webkit-keyframes pacman-balls {75% {opacity: .7}to {transform: translate(-100px, -6.25px)}}
@keyframes pacman-balls {75% {opacity: .7}to {transform: translate(-100px, -6.25px)}}
.loading-image div:nth-child(3),
.loading-image div:nth-child(4),
.loading-image div:nth-child(5),
.loading-image div:nth-child(6){
background-color: #49b1f5;
width: 15px;
height: 15px;
border-radius: 100%;
margin: 2px;
width: 10px;
height: 10px;
position: absolute;
transform: translateY(-6.25px);
top: 25px;
left: 100px;
}
.loading-text{
margin-bottom: 20vh;
text-align: center;
color: #2c3e50;
font-size: 2rem;
box-sizing: border-box;
padding: 0 10px;
text-shadow: 0 2px 10px rgba(0,0,0,0.2);
}
@media only screen and (max-width: 500px) {
.loading-text{
font-size: 1.5rem;
}
}
.fadeout {
opacity: 0;
filter: alpha(opacity=0);
}
/* logo���ֶ��� */
@-webkit-keyframes fadeInDown{0%{opacity:0;-webkit-transform:translate3d(0,-100%,0);transform:translate3d(0,-100%,0)}100%{opacity:1;-webkit-transform:none;transform:none}}
@keyframes fadeInDown{0%{opacity:0;-webkit-transform:translate3d(0,-100%,0);}}
</style>
<script>
(function () {
const loaded = function(){
setTimeout(function(){
const loader = document.getElementById("loading-container");
loader.className="fadeout" ;//ʹ�ý����ķ�������loading page
// document.getElementById("body-wrap").style.display="flex";
setTimeout(function(){
loader.style.display="none";
},1000);
},1000);//ǿ����ʾloading page 1s
};
loaded();
})()
</script></head>
<div id="loading-container">
<p class="loading-text"></p>
<div class="loading-image">
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
</div>
</div><body>
<header class="navbar-fixed">
<nav id="headNav" class="bg-color nav-transparent">
<div id="navContainer" class="nav-wrapper container">
<div class="brand-logo">
<a href="/" class="waves-effect waves-light">
<img src="/medias/logo.png" class="logo-img" alt="LOGO">
<span class="logo-span">Ji`s Blog</span>
</a>
</div>
<a href="#" data-target="mobile-nav" class="sidenav-trigger button-collapse"><i class="fa fa-navicon"></i></a>
<ul class="right">
<li class="hide-on-med-and-down">
<a href="/" class="waves-effect waves-light">
<span>首页</span>
</a>
</li>
<li class="hide-on-med-and-down">
<a href="/tags" class="waves-effect waves-light">
<span>标签</span>
</a>
</li>
<li class="hide-on-med-and-down">
<a href="/categories" class="waves-effect waves-light">
<span>分类</span>
</a>
</li>
<li class="hide-on-med-and-down">
<a href="/archives" class="waves-effect waves-light">
<span>归档</span>
</a>
</li>
<li class="hide-on-med-and-down">
<a href="/about" class="waves-effect waves-light">
<span>关于</span>
</a>
</li>
<li class="hide-on-med-and-down">
<a href="/friends" class="waves-effect waves-light">
<span>友情链接</span>
</a>
</li>
<li class="hide-on-med-and-down">
<a href="/contact" class="waves-effect waves-light">
<span>留言板</span>
</a>
</li>
<li>
<a href="#searchModal" class="modal-trigger waves-effect waves-light">
<i id="searchIcon" class="fa fa-search" title="搜索"></i>
</a>
</li>
</ul>
<div id="mobile-nav" class="side-nav sidenav">
<div class="mobile-head bg-color">
<img src="/medias/logo.png" class="logo-img circle responsive-img">
<div class="logo-name">Ji`s Blog</div>
<div class="logo-desc">
Java | Spring | Redis
</div>
</div>
<ul class="menu-list mobile-menu-list">
<li>
<a href="/" class="waves-effect waves-light">
<i class="fa fa-fw fa-link"></i>
首页
</a>
</li>
<li>
<a href="/tags" class="waves-effect waves-light">
<i class="fa fa-fw fa-link"></i>
标签
</a>
</li>
<li>
<a href="/categories" class="waves-effect waves-light">
<i class="fa fa-fw fa-link"></i>
分类
</a>
</li>
<li>
<a href="/archives" class="waves-effect waves-light">
<i class="fa fa-fw fa-link"></i>
归档
</a>
</li>
<li>
<a href="/about" class="waves-effect waves-light">
<i class="fa fa-fw fa-link"></i>
关于
</a>
</li>
<li>
<a href="/friends" class="waves-effect waves-light">
<i class="fa fa-fw fa-link"></i>
友情链接
</a>
</li>
<li>
<a href="/contact" class="waves-effect waves-light">
<i class="fa fa-fw fa-link"></i>
留言板
</a>
</li>
<li><div class="divider"></div></li>
<li>
<a href="https://github.com/jiyongg-code" class="waves-effect waves-light" target="_blank">
<i class="fa fa-github-square fa-fw"></i>Fork Me
</a>
</li>
</ul>
</div>
</div>
<style>
.nav-transparent .github-corner {
display: none !important;
}
.github-corner {
position: absolute;
z-index: 10;
top: 0;
right: 0;
border: 0;
transform: scale(1.1);
}
.github-corner svg {
color: #0f9d58;
fill: #fff;
height: 64px;
width: 64px;
}
.github-corner:hover .octo-arm {
animation: a 0.56s ease-in-out;
}
.github-corner .octo-arm {
animation: none;
}
@keyframes a {
0%,
to {
transform: rotate(0);
}
20%,
60% {
transform: rotate(-25deg);
}
40%,
80% {
transform: rotate(10deg);
}
}
</style>
<a href="https://github.com/jiyongg-code" class="github-corner tooltipped hide-on-med-and-down" target="_blank"
data-tooltip="Fork Me" data-position="left" data-delay="50">
<svg viewBox="0 0 250 250" aria-hidden="true">
<path d="M0,0 L115,115 L130,115 L142,142 L250,250 L250,0 Z"></path>
<path d="M128.3,109.0 C113.8,99.7 119.0,89.6 119.0,89.6 C122.0,82.7 120.5,78.6 120.5,78.6 C119.2,72.0 123.4,76.3 123.4,76.3 C127.3,80.9 125.5,87.3 125.5,87.3 C122.9,97.6 130.6,101.9 134.4,103.2"
fill="currentColor" style="transform-origin: 130px 106px;" class="octo-arm"></path>
<path d="M115.0,115.0 C114.9,115.1 118.7,116.5 119.8,115.4 L133.7,101.6 C136.9,99.2 139.9,98.4 142.2,98.6 C133.8,88.0 127.5,74.4 143.8,58.0 C148.5,53.4 154.0,51.2 159.7,51.0 C160.3,49.4 163.2,43.6 171.4,40.1 C171.4,40.1 176.1,42.5 178.8,56.2 C183.1,58.6 187.2,61.8 190.9,65.4 C194.5,69.0 197.7,73.2 200.1,77.6 C213.8,80.2 216.3,84.9 216.3,84.9 C212.7,93.1 206.9,96.0 205.4,96.6 C205.1,102.4 203.0,107.8 198.3,112.5 C181.9,128.9 168.3,122.5 157.7,114.1 C157.9,116.9 156.7,120.9 152.7,124.9 L141.0,136.5 C139.8,137.7 141.6,141.9 141.8,141.8 Z"
fill="currentColor" class="octo-body"></path>
</svg>
</a>
</nav>
</header>
<script src="/libs/cryptojs/crypto-js.min.js"></script>
<script>
(function() {
let pwd = '';
if (pwd && pwd.length > 0) {
if (pwd !== CryptoJS.SHA256(prompt('请输入访问本文章的密码')).toString(CryptoJS.enc.Hex)) {
alert('密码错误，将返回主页！');
location.href = '/';
}
}
})();
</script>
<div class="bg-cover pd-header post-cover" style="background-image: url('/medias/featureimages/21.jpg')">
<div class="container">
<div class="row">
<div class="col s12 m12 l12">
<div class="brand">
<div class="description center-align post-title">
CompletableFuture 异步编程
</div>
</div>
</div>
</div>
</div>
</div>
<main class="post-container content">
<link rel="stylesheet" href="/libs/tocbot/tocbot.css">
<style>
#articleContent h1::before,
#articleContent h2::before,
#articleContent h3::before,
#articleContent h4::before,
#articleContent h5::before,
#articleContent h6::before {
display: block;
content: " ";
height: 100px;
margin-top: -100px;
visibility: hidden;
}
#articleContent :focus {
outline: none;
}
.toc-fixed {
position: fixed;
top: 64px;
}
.toc-widget {
padding-left: 20px;
}
.toc-widget .toc-title {
margin: 35px 0 15px 0;
padding-left: 17px;
font-size: 1.5rem;
font-weight: bold;
line-height: 1.5rem;
}
.toc-widget ol {
padding: 0;
list-style: none;
}
#toc-content ol {
padding-left: 10px;
}
#toc-content ol li {
padding-left: 10px;
}
#toc-content .toc-link:hover {
color: #42b983;
font-weight: 700;
text-decoration: underline;
}
#toc-content .toc-link::before {
background-color: transparent;
max-height: 25px;
}
#toc-content .is-active-link {
color: #42b983;
}
#toc-content .is-active-link::before {
background-color: #42b983;
}
#floating-toc-btn {
position: fixed;
right: 20px;
bottom: 76px;
padding-top: 15px;
margin-bottom: 0;
z-index: 998;
}
#floating-toc-btn .btn-floating {
width: 48px;
height: 48px;
}
#floating-toc-btn .btn-floating i {
line-height: 48px;
font-size: 1.4rem;
}
</style>
<div class="row">
<div id="main-content" class="col s12 m12 l9">
<!-- 文章内容详情 -->
<div id="artDetail">
<div class="card">
<div class="card-content article-info">
<div class="row tag-cate">
<div class="col s7">
<div class="article-tag">
<span class="chip bg-color">无标签</span>
</div>
</div>
<div class="col s5 right-align">
</div>
</div>
<div class="post-info">
<div class="post-date info-break-policy">
<i class="fa fa-calendar-minus-o fa-fw"></i>发布日期:
2023-09-27
</div>
<div class="post-author info-break-policy">
<i class="fa fa-user-o fa-fw"></i>作者:
jiyonggang
</div>
<div class="info-break-policy">
<i class="fa fa-file-word-o fa-fw"></i>文章字数:
3.8k
</div>
<div class="info-break-policy">
<i class="fa fa-clock-o fa-fw"></i>阅读时长:
15 分
</div>
<div id="busuanzi_container_page_pv" class="info-break-policy">
<i class="fa fa-eye fa-fw"></i>阅读次数:
<span id="busuanzi_value_page_pv"></span>
</div>
</div>
</div>
<hr class="clearfix">
<div class="card-content article-card-content">
<div id="articleContent">
<h1 id="创建异步任务"><a href="#创建异步任务" class="headerlink" title="创建异步任务"></a>创建异步任务</h1><p>CompletableFuture创建异步任务，一般有supplyAsync和runAsync两个方法</p>
<ul>
<li>supplyAsync执行CompletableFuture任务，支持返回值</li>
<li>runAsync执行CompletableFuture任务，没有返回值。</li>
</ul>
<h2 id="supplyAsync方法"><a href="#supplyAsync方法" class="headerlink" title="supplyAsync方法"></a>supplyAsync方法</h2><pre><code>//使用默认内置线程池ForkJoinPool.commonPool()，根据supplier构建执行任务
public static <U> CompletableFuture<U> supplyAsync(Supplier<U> supplier)
//自定义线程，根据supplier构建执行任务
public static <U> CompletableFuture<U> supplyAsync(Supplier<U> supplier, Executor executor)
</code></pre><h2 id="runAsync方法"><a href="#runAsync方法" class="headerlink" title="runAsync方法"></a>runAsync方法</h2><pre><code>//使用默认内置线程池ForkJoinPool.commonPool()，根据runnable构建执行任务
public static CompletableFuture<Void> runAsync(Runnable runnable)
//自定义线程，根据runnable构建执行任务
public static CompletableFuture<Void> runAsync(Runnable runnable, Executor executor)
</code></pre><pre><code>public class FutureTest {
public static void main(String[] args) {
//可以自定义线程池
ExecutorService executor = Executors.newCachedThreadPool();
//runAsync的使用
CompletableFuture<Void> runFuture = CompletableFuture.runAsync(() -> System.out.println("run,cc"), executor);
//supplyAsync的使用
CompletableFuture<String> supplyFuture = CompletableFuture.supplyAsync(() -> {
System.out.print("supply,ccc");
return "ccc"; }, executor);
//runAsync的future没有返回值，输出null
System.out.println(runFuture.join());
//supplyAsync的future，有返回值
System.out.println(supplyFuture.join());
executor.shutdown(); // 线程池需要关闭
}
}
//输出
run,cc
null
supply,ccc
</code></pre><p>join方法</p>
<p><strong>完成</strong>后返回结果值，如果异常完成，则引发（未选中）异常。为了更好地符合常见函数形式的使用，如果完成此 CompletableFuture 所涉及的计算抛出异常，则此方法会抛出一个（未选中） CompletionException 以基础异常作为其原因。<br>返回：<br>结果值<br>抛出：<br>CancellationException – 如果计算被取消<br>CompletionException – 如果此未来异常完成或完成计算引发异常</p>
<h1 id="任务异步回调"><a href="#任务异步回调" class="headerlink" title="任务异步回调"></a>任务异步回调</h1><pre><code>public CompletableFuture<Void> thenRun(Runnable action);
public CompletableFuture<Void> thenRunAsync(Runnable action);</code></pre><h2 id="thenRun-thenRunAsync"><a href="#thenRun-thenRunAsync" class="headerlink" title="thenRun/thenRunAsync"></a>thenRun/thenRunAsync</h2><p>CompletableFuture的thenRun方法，通俗点讲就是，<strong>做完第一个任务后，再做第二个任务</strong>。某个任务执行完成后，执行回调方法；但是前后两个任务<strong>没有参数传递，第二个任务也没有返回值</strong></p>
<pre><code>public class FutureThenRunTest {
public static void main(String[] args) throws ExecutionException, InterruptedException {
CompletableFuture<String> orgFuture = CompletableFuture.supplyAsync(
()->{
System.out.println("先执行第一个CompletableFuture方法任务");
return "第一个";
}
);
CompletableFuture thenRunFuture = orgFuture.thenRun(() -> {
System.out.println("接着执行第二个任务");
});
System.out.println(thenRunFuture.get());
}
}
//输出
先执行第一个CompletableFuture方法任务
接着执行第二个任务
null
</code></pre><p>get方法</p>
<p>如有必要，等待此未来完成，然后返回其结果。<br>返回：<br>结果值<br>抛出：<br>CancellationException – 如果这个未来被取消<br>ExecutionException – 如果这个未来特别完成<br>InterruptedException – 如果当前线程在等待时中断</p>
<p>方法值会阻塞主线程，直到子线程执行任务完成返回结果才会取消阻塞。如果子线程一直不返回接口那么主线程就会一直阻塞</p>
<h2 id="thenRun-和thenRunAsync有什么区别"><a href="#thenRun-和thenRunAsync有什么区别" class="headerlink" title="thenRun 和thenRunAsync有什么区别"></a><strong>thenRun 和thenRunAsync有什么区别</strong></h2><p>如果你执行第一个任务的时候，传入了一个自定义线程池：</p>
<ul>
<li>调用thenRun方法执行第二个任务时，则第二个任务和第一个任务是<strong>共用同一个线程池</strong>。</li>
<li>调用thenRunAsync执行第二个任务时，则第一个任务使用的是你自己传入的线程池，<strong>第二个任务使用的是ForkJoin线程池</strong></li>
</ul>
<p>thenAccept和thenAcceptAsync，thenApply和thenApplyAsync等，它们之间的区别也是这个哈。</p>
<h2 id="thenAccept-thenAcceptAsync"><a href="#thenAccept-thenAcceptAsync" class="headerlink" title="thenAccept/thenAcceptAsync"></a>thenAccept/thenAcceptAsync</h2><p>CompletableFuture的thenAccept方法表示，第一个任务执行完成后，执行第二个回调方法任务，会将该任务的执行结果，作为入参，传递到回调方法中，但是回调方法是<strong>没有返回值</strong>的。</p>
<pre><code>public class FutureThenAcceptTest {
public static void main(String[] args) throws ExecutionException, InterruptedException {
CompletableFuture<String> orgFuture = CompletableFuture.supplyAsync(
()->{
System.out.println("原始CompletableFuture方法任务");
return "cc";
}
);
CompletableFuture thenAcceptFuture = orgFuture.thenAccept((a) -> {
if ("ccc".equals(a)) {
System.out.println("关注了");
}
System.out.println("先考虑考虑");
});
System.out.println(thenAcceptFuture.get());
}
}
</code></pre><h2 id="thenApply-thenApplyAsync"><a href="#thenApply-thenApplyAsync" class="headerlink" title="thenApply/thenApplyAsync"></a>thenApply/thenApplyAsync</h2><p>CompletableFuture的thenApply方法表示，第一个任务执行完成后，执行第二个回调方法任务，会将该任务的执行结果，作为入参，传递到回调方法中，并且回调方法是<strong>有返回值的。</strong></p>
<pre><code>public class FutureThenApplyTest {
public static void main(String[] args) throws ExecutionException, InterruptedException {
CompletableFuture<String> orgFuture = CompletableFuture.supplyAsync(
()->{
System.out.println("原始CompletableFuture方法任务");
return "ccc";
}
);
CompletableFuture<String> thenApplyFuture = orgFuture.thenApply((a) -> {
if ("ccc".equals(a)) {
return "aaa";
}
return "先考虑考虑";
});
System.out.println(thenApplyFuture.get());
}
}
//输出
原始CompletableFuture方法任务
aa
</code></pre><h2 id="exceptionally"><a href="#exceptionally" class="headerlink" title="exceptionally"></a>exceptionally</h2><p>CompletableFuture的exceptionally方法表示，某个任务执行异常时，执行的回调方法;并且有<strong>抛出异常作为参数</strong>，传递到回调方法。</p>
<pre><code>public class FutureExceptionTest {
public static void main(String[] args) throws ExecutionException, InterruptedException {
CompletableFuture<String> orgFuture = CompletableFuture.supplyAsync(
()->{
System.out.println("当前线程名称：" + Thread.currentThread().getName());
throw new RuntimeException();
}
);
CompletableFuture<String> exceptionFuture = orgFuture.exceptionally((e) -> {
e.printStackTrace();
return "你的程序异常啦";
});
System.out.println(exceptionFuture.get());
}
}
//输出
当前线程名称：ForkJoinPool.commonPool-worker-1
java.util.concurrent.CompletionException: java.lang.RuntimeException
at java.util.concurrent.CompletableFuture.encodeThrowable(CompletableFuture.java:273)
at java.util.concurrent.CompletableFuture.completeThrowable(CompletableFuture.java:280)
at java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1592)
at java.util.concurrent.CompletableFuture$AsyncSupply.exec(CompletableFuture.java:1582)
at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)
at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)
Caused by: java.lang.RuntimeException
at cn.eovie.future.FutureWhenTest.lambda$main$0(FutureWhenTest.java:13)
at java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1590)
... 5 more
你的程序异常啦
</code></pre><h2 id="whenComplete方法"><a href="#whenComplete方法" class="headerlink" title="whenComplete方法"></a>whenComplete方法</h2><p>CompletableFuture的whenComplete方法表示，某个任务执行完成后，执行的回调方法，<strong>无返回值</strong>；并且whenComplete方法返回的CompletableFuture的<strong>result是上个任务的结果</strong>。不论是正常完成还是出现异常</p>
<p>CompletableFuture的whenComplete方法是一个回调函数，它表示当一个异步任务完成时，执行的动作。它有两个参数，一个是上个任务的结果，一个是上个任务的异常。如果上个任务正常完成，那么结果参数就是上个任务的返回值，异常参数就是null。如果上个任务出现异常，那么结果参数就是null，异常参数就是上个任务的异常。whenComplete方法返回的CompletableFuture的结果和上个任务一致，不会被回调函数的动作改变。</p>
<pre><code>public class FutureWhenTest {
public static void main(String[] args) throws ExecutionException, InterruptedException {
CompletableFuture<String> orgFuture = CompletableFuture.supplyAsync(
()->{
System.out.println("当前线程名称：" + Thread.currentThread().getName());
try {
Thread.sleep(2000L);
} catch (InterruptedException e) {
e.printStackTrace();
}
return "cc";
}
);
CompletableFuture<String> rstFuture = orgFuture.whenComplete((a, throwable) -> {
System.out.println("当前线程名称：" + Thread.currentThread().getName());
System.out.println("上个任务执行完啦，还把" + a + "传过来");
if ("ccc".equals(a)) {
System.out.println("666");
}
System.out.println("233333");
});
System.out.println(rstFuture.get());
}
}
//输出
当前线程名称：ForkJoinPool.commonPool-worker-1
当前线程名称：ForkJoinPool.commonPool-worker-1
上个任务执行完啦，还把捡田螺的小男孩传过来
666
233333
ccc
</code></pre><h2 id="handle方法"><a href="#handle方法" class="headerlink" title="handle方法"></a>handle方法</h2><p>CompletableFuture的handle方法表示，<strong>某个任务执行完成后，执行回调方法，并且是有返回值的</strong>;并且handle方法返回的CompletableFuture的result是<strong>回调方法</strong>执行的结果。</p>
<p>CompletableFuture的handle方法是一个回调函数，它表示当一个异步任务完成时，执行的动作。它有两个参数，一个是上个任务的结果，一个是上个任务的异常。如果上个任务正常完成，那么结果参数就是上个任务的返回值，异常参数就是null。如果上个任务出现异常，那么结果参数就是null，异常参数就是上个任务的异常。handle方法返回的CompletableFuture的结果可以由回调函数的动作改变，也就是说可以对上个任务的结果进行转换或者恢复。</p>
<h2 id="whenComplete和handle，exceptionally的区别"><a href="#whenComplete和handle，exceptionally的区别" class="headerlink" title="whenComplete和handle，exceptionally的区别"></a>whenComplete和handle，exceptionally的区别</h2><p>handle方法和whenComplete方法的区别主要有以下几点 ：</p>
<ul>
<li>handle方法可以对上个任务的结果进行转换或者恢复，也就是说可以返回一个不同类型的值，而whenComplete方法不能转换结果，只能返回和上个任务相同类型的值。</li>
<li>handle方法可以从异常中恢复，也就是说可以返回一个正常的值，而whenComplete方法不能从异常中恢复，只能抛出异常或者忽略异常。</li>
<li>handle方法和whenComplete方法都会在正常或异常完成时执行，但是handle方法会根据不同的情况返回不同的值，而whenComplete方法只会执行一些操作，不会影响返回值。</li>
</ul>
<p>使用 CompletableFuture 编写代码时，异常处理很重要。<br>CompletableFuture 提供了三种方法来处理它们：handle()、whenComplete() 和 exceptionly()。</p>
<table>
<thead>
<tr>
<th></th>
<th>handle()</th>
<th>whenComplete()</th>
<th>exceptionly()</th>
</tr>
</thead>
<tbody><tr>
<td>访问成功</td>
<td>Yes</td>
<td>Yes</td>