{"id":3946,"date":"2025-07-20T11:10:37","date_gmt":"2025-07-20T03:10:37","guid":{"rendered":"https:\/\/www.laixuexila.com\/?p=3946"},"modified":"2025-07-20T11:10:37","modified_gmt":"2025-07-20T03:10:37","slug":"signal-vs-signalall-%e7%9a%84%e8%b0%83%e5%ba%a6%e7%ad%96%e7%95%a5%e5%92%8c%e9%80%82%e7%94%a8%e5%9c%ba%e6%99%af%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/www.laixuexila.com\/index.php\/2025\/07\/20\/signal-vs-signalall-%e7%9a%84%e8%b0%83%e5%ba%a6%e7%ad%96%e7%95%a5%e5%92%8c%e9%80%82%e7%94%a8%e5%9c%ba%e6%99%af%ef%bc%9f\/","title":{"rendered":"signal vs signalAll \u7684\u8c03\u5ea6\u7b56\u7565\u548c\u9002\u7528\u573a\u666f\uff1f"},"content":{"rendered":"\n<p><code>sinal()<\/code> vs <code>signalAll()<\/code> \u662f Java \u5e76\u53d1\u63a7\u5236\u4e2d <code>Condition<\/code> \u63a5\u53e3\u7684\u4e24\u4e2a\u6838\u5fc3\u65b9\u6cd5\uff0c\u5b83\u4eec\u63a7\u5236\u7684\u662f<strong>\u7b49\u5f85\u6761\u4ef6\u961f\u5217\u4e2d\u7ebf\u7a0b\u7684\u5524\u9192\u7b56\u7565<\/strong>\u3002\u4e24\u8005\u5728\u529f\u80fd\u3001\u6548\u7387\u4e0e\u9002\u7528\u573a\u666f\u4e0a\u5b58\u5728\u663e\u8457\u533a\u522b\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u4e00\u3001\u57fa\u672c\u6982\u5ff5\u6982\u89c8<\/h2>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u65b9\u6cd5\u540d<\/th><th>\u5524\u9192\u7ebf\u7a0b\u6570\u91cf<\/th><th>\u8c03\u5ea6\u673a\u5236<\/th><th>\u662f\u5426\u53d7\u8c03\u5ea6\u987a\u5e8f\u5f71\u54cd<\/th><\/tr><\/thead><tbody><tr><td><code>signal()<\/code><\/td><td>\u5524\u9192<strong>\u4e00\u4e2a<\/strong>\u7ebf\u7a0b<\/td><td>FIFO or JVM\u8c03\u5ea6\u4f18\u5316<\/td><td>\u6709\u65f6\u4e0d\u53ef\u63a7<\/td><\/tr><tr><td><code>signalAll()<\/code><\/td><td>\u5524\u9192<strong>\u6240\u6709<\/strong>\u7ebf\u7a0b<\/td><td>\u4e00\u6b21\u6027\u5168\u90e8\u5524\u9192<\/td><td>\u4e0d\u4f9d\u8d56\u987a\u5e8f<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u4e8c\u3001Condition \u7684\u7b49\u5f85\u961f\u5217\u7b80\u8981\u539f\u7406<\/h2>\n\n\n\n<p><code>Condition.await()<\/code> \u4f1a\u8ba9\u7ebf\u7a0b\u8fdb\u5165\u4e00\u4e2a<strong>\u6761\u4ef6\u961f\u5217<\/strong>\uff08ConditionQueue\uff09\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u8fd9\u4e9b\u7ebf\u7a0b\u4f1a\u5728\u6761\u4ef6\u6210\u7acb\u4e4b\u524d<strong>\u6302\u8d77\u7b49\u5f85<\/strong>\u3002<\/li>\n\n\n\n<li>\u5524\u9192\u8fd9\u4e9b\u7ebf\u7a0b\u7684\u65b9\u5f0f\u5c31\u662f\u901a\u8fc7 <code>signal()<\/code> \u6216 <code>signalAll()<\/code>\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u5185\u90e8\u4f9d\u8d56 <code>AQS<\/code>\uff08AbstractQueuedSynchronizer\uff09\u5b9e\u73b0\u7ebf\u7a0b\u963b\u585e\u4e0e\u5524\u9192\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u4e09\u3001\u4e24\u8005\u6838\u5fc3\u5dee\u5f02\u8be6\u89e3<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">1. <code>signal()<\/code>\uff1a\u53ea\u5524\u9192<strong>\u961f\u9996\u7b2c\u4e00\u4e2a\u7b49\u5f85\u7ebf\u7a0b<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u901a\u5e38\u7528\u4e8e\u6709<strong>\u552f\u4e00\u8d44\u6e90<\/strong>\u7ade\u4e89\u65f6\u3002<\/li>\n\n\n\n<li>\u5982\u679c\u6761\u4ef6\u4e0d\u6ee1\u8db3\uff0c\u5176\u5b83\u7ebf\u7a0b\u4ecd\u4f1a\u4fdd\u6301\u7b49\u5f85\u3002<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\">\u793a\u4f8b\u573a\u666f\uff1a<\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>lock.lock();\ntry {\n    while (!queue.isEmpty()) {\n        condition.await();\n    }\n    \/\/ \u5904\u7406\u5b8c\u4efb\u52a1\n    condition.signal(); \/\/ \u5524\u9192\u4e0b\u4e00\u4e2a\n} finally {\n    lock.unlock();\n}<\/code><\/pre>\n\n\n\n<p><strong>\u98ce\u9669<\/strong>\uff1a\u82e5\u88ab\u5524\u9192\u7684\u7ebf\u7a0b\u4e0d\u6ee1\u8db3\u6761\u4ef6\uff0c\u4f1a\u91cd\u65b0\u7b49\u5f85\uff0c\u9020\u6210<strong>\u4f2a\u5524\u9192\u6d6a\u8d39<\/strong>\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">2. <code>signalAll()<\/code>\uff1a\u5524\u9192<strong>\u6240\u6709\u7b49\u5f85\u7ebf\u7a0b<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u6240\u6709\u5728 Condition \u4e0a\u7b49\u5f85\u7684\u7ebf\u7a0b\u90fd\u4f1a\u88ab\u5524\u9192\u3002<\/li>\n\n\n\n<li>\u6bcf\u4e2a\u7ebf\u7a0b\u9192\u6765\u540e\u9700\u8981\u91cd\u65b0\u68c0\u67e5\u6761\u4ef6\uff08\u5178\u578b\u7684\u201c<code>while<\/code>-check\u201d\u6a21\u5f0f\uff09<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\">\u793a\u4f8b\u573a\u666f\uff1a<\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>lock.lock();\ntry {\n    \/\/ \u72b6\u6001\u53d8\u5316\u6240\u6709\u4eba\u90fd\u8981\u77e5\u9053\n    sharedStateChanged = true;\n    condition.signalAll(); \/\/ \u6240\u6709\u4eba\u90fd\u68c0\u67e5\n} finally {\n    lock.unlock();\n}<\/code><\/pre>\n\n\n\n<p>\u6bd4\u5982\uff1a\u914d\u7f6e\u66f4\u65b0\u3001\u7f13\u5b58\u91cd\u5efa\u3001\u6240\u6709\u6d88\u8d39\u8005\u90fd\u53ef\u80fd\u53d7\u5f71\u54cd\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u56db\u3001\u4e3a\u4ec0\u4e48\u63a8\u8350 <code>signalAll()<\/code> \u642d\u914d <code>while<\/code>\uff1f<\/h2>\n\n\n\n<p>\u56e0\u4e3a\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u865a\u5047\u5524\u9192\uff08Spurious Wakeup\uff09<\/strong>\uff1aJVM \u53ef\u80fd\u968f\u65f6\u5524\u9192\u7ebf\u7a0b\uff1b<\/li>\n\n\n\n<li><strong>\u6761\u4ef6\u7ade\u4e89<\/strong>\uff1a\u5524\u9192\u540e\u53d1\u73b0<strong>\u6761\u4ef6\u4ecd\u4e0d\u6ee1\u8db3<\/strong>\u7684\u53ef\u80fd\u6027\u6781\u9ad8\u3002<\/li>\n<\/ol>\n\n\n\n<pre class=\"wp-block-code\"><code>while (!\u6761\u4ef6\u6ee1\u8db3) {\n    condition.await();\n}<\/code><\/pre>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u4e94\u3001\u6027\u80fd\u5bf9\u6bd4\u548c\u8c03\u5ea6\u7b56\u7565<\/h2>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u9879\u76ee<\/th><th><code>signal()<\/code><\/th><th><code>signalAll()<\/code><\/th><\/tr><\/thead><tbody><tr><td>\u5524\u9192\u7ebf\u7a0b\u6570<\/td><td>\u6700\u591a\u4e00\u4e2a<\/td><td>\u6240\u6709\u7b49\u5f85\u7ebf\u7a0b<\/td><\/tr><tr><td>\u5f00\u9500\uff08\u7ebf\u7a0b\u8c03\u5ea6\uff09<\/td><td>\u8f83\u4f4e<\/td><td>\u8f83\u9ad8\uff0c\u53ef\u80fd\u5f15\u53d1\u201c\u60ca\u7fa4\u6548\u5e94\u201d<\/td><\/tr><tr><td>\u662f\u5426\u9002\u5408\u9ad8\u9891\u8c03\u5ea6\u573a\u666f<\/td><td>\u662f<\/td><td>\u5426<\/td><\/tr><tr><td>\u4f7f\u7528\u524d\u63d0<\/td><td>\u961f\u5217\u4e2d\u7ebf\u7a0b\u53ef\u72ec\u7acb\u6761\u4ef6\u68c0\u67e5<\/td><td>\u5524\u9192\u540e\u5fc5\u987b\u91cd\u65b0\u9a8c\u8bc1\u5171\u4eab\u72b6\u6001<\/td><\/tr><tr><td>\u63a8\u8350\u4f7f\u7528\u7684\u5178\u578b\u573a\u666f<\/td><td>\u961f\u5217\u6a21\u578b \/ \u5355\u4e2a\u8d44\u6e90\u7ade\u4e89<\/td><td>\u591a\u7ebf\u7a0b\u4f9d\u8d56\u540c\u4e00\u5171\u4eab\u6761\u4ef6\u7684\u53d8\u5316<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u516d\u3001\u5b9e\u9645\u5e94\u7528\u573a\u666f\u5206\u6790<\/h2>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u573a\u666f<\/th><th>\u63a8\u8350\u65b9\u6cd5<\/th><th>\u539f\u56e0\u8bf4\u660e<\/th><\/tr><\/thead><tbody><tr><td><strong>\u751f\u4ea7\u8005-\u6d88\u8d39\u8005\u6a21\u578b<\/strong><\/td><td><code>signal()<\/code><\/td><td>\u53ea\u9700\u8981\u5524\u9192\u4e00\u4e2a\u6d88\u8d39\u8005\u6216\u751f\u4ea7\u8005\uff0c\u907f\u514d\u60ca\u7fa4<\/td><\/tr><tr><td><strong>\u8d44\u6e90\u6c60\u7ba1\u7406\uff08\u8fde\u63a5\u6c60\uff09<\/strong><\/td><td><code>signal()<\/code><\/td><td>\u83b7\u53d6\u8fde\u63a5\u7684\u7ebf\u7a0b\u4e00\u4e2a\u4e00\u4e2a\u5524\u9192\u5373\u53ef<\/td><\/tr><tr><td><strong>\u914d\u7f6e\u4e2d\u5fc3\u66f4\u65b0\u901a\u77e5<\/strong><\/td><td><code>signalAll()<\/code><\/td><td>\u914d\u7f6e\u53d8\u66f4\u6240\u6709\u4f9d\u8d56\u7ebf\u7a0b\u90fd\u9700\u8981\u77e5\u9053<\/td><\/tr><tr><td><strong>\u7ebf\u7a0b\u5c4f\u969c\uff08\u5982 CountDownLatch\uff09<\/strong><\/td><td><code>signalAll()<\/code><\/td><td>\u6240\u6709\u7b49\u5f85\u7ebf\u7a0b\u540c\u65f6\u7ee7\u7eed\u6267\u884c<\/td><\/tr><tr><td><strong>\u5168\u5c40\u9519\u8bef\u72b6\u6001\u5207\u6362<\/strong><\/td><td><code>signalAll()<\/code><\/td><td>\u6240\u6709\u7b49\u5f85\u7ebf\u7a0b\u90fd\u5e94\u7acb\u5373\u88ab\u5524\u9192\u54cd\u5e94<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u4e03\u3001\u6e90\u7801\u89e3\u6790\uff08\u7b80\u8981\uff09<\/h2>\n\n\n\n<pre class=\"wp-block-code\"><code>public final void signal() {\n    if (!isHeldExclusively())\n        throw new IllegalMonitorStateException();\n    Node first = firstWaiter;\n    if (first != null)\n        doSignal(first);\n}\n\npublic final void signalAll() {\n    if (!isHeldExclusively())\n        throw new IllegalMonitorStateException();\n    Node first = firstWaiter;\n    if (first != null)\n        doSignalAll(first);\n}<\/code><\/pre>\n\n\n\n<p>\u5185\u90e8\u4f1a\u5c06\u6761\u4ef6\u961f\u5217\u4e2d\u7684\u7ebf\u7a0b\u8282\u70b9\u8f6c\u79fb\u5230 AQS \u7684\u540c\u6b65\u961f\u5217\u4e2d\uff0c\u5524\u9192\u987a\u5e8f\u89c6 JVM \u7ebf\u7a0b\u8c03\u5ea6\u800c\u5b9a\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u516b\u3001\u5b9e\u6218\u5bf9\u6bd4\u6848\u4f8b\uff08\u7b80\u5316\uff09<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">\u793a\u4f8b\uff1a\u7ebf\u7a0b A\/B\/C \u5728\u7b49\u5f85\u5171\u4eab\u6761\u4ef6<\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code>\/\/ \u7ebf\u7a0b A\/B\/C\nlock.lock();\ntry {\n    while (!dataReady) {\n        condition.await(); \/\/ \u5168\u90e8\u8fdb\u5165 Condition \u961f\u5217\n    }\n    \/\/ \u6267\u884c\u8bfb\u53d6\n} finally {\n    lock.unlock();\n}<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\">\u4f7f\u7528 <code>signal()<\/code>\uff1a<\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>\/\/ \u901a\u77e5\u7ebf\u7a0b\nlock.lock();\ndataReady = true;\ncondition.signal(); \/\/ \u53ea\u5524\u9192\u4e00\u4e2a\u7ebf\u7a0b\nlock.unlock();<\/code><\/pre>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u2795 \u8f7b\u91cf\u3001\u8282\u7701 CPU<\/li>\n\n\n\n<li>\u2796 \u5269\u4e0b\u7684\u7ebf\u7a0b\u7ee7\u7eed\u963b\u585e\uff0c\u82e5\u4e1a\u52a1\u903b\u8f91\u9700\u591a\u7ebf\u7a0b\u53cd\u5e94\uff0c\u5c31\u4e0d\u8db3<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\">\u4f7f\u7528 <code>signalAll()<\/code>\uff1a<\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>lock.lock();\ndataReady = true;\ncondition.signalAll(); \/\/ \u5524\u9192\u6240\u6709\u7ebf\u7a0b\nlock.unlock();<\/code><\/pre>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u2795 \u6240\u6709\u7ebf\u7a0b\u68c0\u67e5\u6761\u4ef6\uff0c\u9002\u5408\u540c\u6b65\u66f4\u65b0<\/li>\n\n\n\n<li>\u2796 \u6240\u6709\u7ebf\u7a0b\u88ab\u5524\u9192\u4f46\u53ef\u80fd\u53c8\u9a6c\u4e0a await\uff0c\u6d6a\u8d39 CPU\uff08\u60ca\u7fa4\uff09<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u4e5d\u3001\u6743\u5a01\u8d44\u6599\u53c2\u8003<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/docs.oracle.com\/javase\/8\/docs\/api\/java\/util\/concurrent\/locks\/Condition.html\">Java \u5b98\u65b9\u6587\u6863 &#8211; Condition \u63a5\u53e3<\/a><\/li>\n\n\n\n<li>\u300aJava Concurrency in Practice\u300b \u2014 \u7b2c 14 \u7ae0<\/li>\n\n\n\n<li><a href=\"https:\/\/github.com\/openjdk\/jdk\/blob\/master\/src\/java.base\/share\/classes\/java\/util\/concurrent\/locks\/AbstractQueuedSynchronizer.java\">OpenJDK AbstractQueuedSynchronizer \u6e90\u7801<\/a><\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u603b\u7ed3\u53e3\u8bc0<\/h2>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>signal \u4e00\u4eba\u8d77\uff0c\u8f7b\u91cf\u5c11\u51b2\u51fb\uff1b<br>signalAll \u7686\u5524\u9192\uff0c\u72b6\u6001\u7edf\u4e00\u9f50\u3002<br>\u6761\u4ef6\u5224\u65ad\u7528 while\uff0c\u865a\u5047\u5524\u9192\u9632\u51b2\u51fb\u3002<\/p>\n<\/blockquote>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p>\u66f4\u591a\u8be6\u7ec6\u5185\u5bb9\u8bf7\u5173\u6ce8\u5176\u4ed6\u76f8\u5173\u6587\u7ae0\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"<p>sinal() vs signalAll() \u662f Java \u5e76\u53d1\u63a7\u5236\u4e2d Condition \u63a5\u53e3\u7684\u4e24\u4e2a\u6838\u5fc3\u65b9\u6cd5 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":3947,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[68,86],"tags":[],"class_list":["post-3946","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-java","category-java-"],"_links":{"self":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/3946","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/comments?post=3946"}],"version-history":[{"count":1,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/3946\/revisions"}],"predecessor-version":[{"id":3948,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/3946\/revisions\/3948"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/media\/3947"}],"wp:attachment":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/media?parent=3946"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/categories?post=3946"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/tags?post=3946"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}