{"id":3910,"date":"2025-07-13T12:01:38","date_gmt":"2025-07-13T04:01:38","guid":{"rendered":"https:\/\/www.laixuexila.com\/?p=3910"},"modified":"2025-07-13T12:01:38","modified_gmt":"2025-07-13T04:01:38","slug":"java-8-%e4%b8%ad%e6%b6%88%e9%99%a4%e4%bc%aa%e5%85%b1%e4%ba%ab%e7%9a%84%e6%9c%80%e4%bd%b3%e5%ae%9e%e8%b7%b5%e4%bb%a3%e7%a0%81","status":"publish","type":"post","link":"https:\/\/www.laixuexila.com\/index.php\/2025\/07\/13\/java-8-%e4%b8%ad%e6%b6%88%e9%99%a4%e4%bc%aa%e5%85%b1%e4%ba%ab%e7%9a%84%e6%9c%80%e4%bd%b3%e5%ae%9e%e8%b7%b5%e4%bb%a3%e7%a0%81\/","title":{"rendered":"Java 8+ \u4e2d\u6d88\u9664\u4f2a\u5171\u4eab\u7684\u6700\u4f73\u5b9e\u8df5\u4ee3\u7801"},"content":{"rendered":"\n

\u5728 Java 8+ \u4e2d\uff0c\u6d88\u9664\u4f2a\u5171\u4eab\u7684\u6700\u4f73\u5b9e\u8df5<\/strong>\u662f\u901a\u8fc7\u4f7f\u7528 @Contended<\/code> \u6ce8\u89e3\u548c\u5408\u7406\u5185\u5b58\u5e03\u5c40\u7b56\u7565\u6765\u907f\u514d\u591a\u4e2a\u7ebf\u7a0b\u9891\u7e41\u5199\u5165\u540c\u4e00\u7f13\u5b58\u884c\uff0c\u4ece\u800c\u63d0\u9ad8\u5e76\u53d1\u6027\u80fd<\/strong>\u3002<\/p>\n\n\n\n

\u4e0b\u9762\u662f\u4ece\u5f00\u53d1\u5b9e\u7528\u89d2\u5ea6\u51fa\u53d1<\/strong>\uff0c\u6574\u7406\u7684 Java 8 \u53ca\u4ee5\u4e0a\u7248\u672c\u4e0b\u6d88\u9664\u4f2a\u5171\u4eab\u7684\u6700\u4f73\u5b9e\u8df5\u4ee3\u7801\u4e0e\u7b56\u7565<\/strong>\uff1a<\/p>\n\n\n\n

\n\n\n\n

\u4e00\u3001\u63a8\u8350\u4f7f\u7528\u65b9\u5f0f\uff1a@Contended<\/code> \u6ce8\u89e3\uff08Java 8+\uff09<\/h2>\n\n\n\n

@Contended<\/code> \u662f Java 8 \u65b0\u589e\u7684\u6ce8\u89e3\uff08\u4f4d\u4e8e jdk.internal.vm.annotation<\/code> \u5305\uff09\uff0c\u7528\u4e8e\u81ea\u52a8\u4e3a\u53d8\u91cf\u586b\u5145\u7a7a\u767d\uff0c\u907f\u514d\u4e0e\u5176\u4ed6\u53d8\u91cf\u5171\u4eab\u7f13\u5b58\u884c<\/strong>\u3002<\/p>\n\n\n\n

\n\n\n\n

\u793a\u4f8b\uff1a\u6d88\u9664\u4f2a\u5171\u4eab\u7684\u8ba1\u6570\u5668\u7c7b<\/h3>\n\n\n\n
import jdk.internal.vm.annotation.Contended;\n\npublic class CounterWithContended {\n\n    @Contended\n    public volatile long value = 0L;\n}<\/code><\/pre>\n\n\n\n
\n\n\n\n
\u4f7f\u7528\u524d\u63d0\uff1a\u5fc5\u987b\u5f00\u542f JVM \u53c2\u6570<\/h3>\n\n\n\n
@Contended<\/code> \u9ed8\u8ba4\u88ab JVM \u9650\u5236\u4f7f\u7528\uff0c\u5fc5\u987b\u4f7f\u7528\u53c2\u6570\u663e\u5f0f\u5f00\u542f\uff1a<\/p>\n\n\n\n
-XX:-RestrictContended<\/code><\/pre>\n\n\n\n
\ud83d\udd14 \u5426\u5219\u6ce8\u89e3\u4e0d\u4f1a\u751f\u6548\uff0c\u5b57\u6bb5\u4e0d\u4f1a\u586b\u5145\u7f13\u5b58\u884c\u5bf9\u9f50\u3002<\/p>\n\n\n\n
\n\n\n\n
\u4e8c\u3001\u5b9e\u6218\u6700\u4f73\u5b9e\u8df5\u4ee3\u7801\uff1a\u591a\u7ebf\u7a0b\u5b89\u5168\u8ba1\u6570\u5668<\/h2>\n\n\n\n
\u5b9e\u6218\u6848\u4f8b\uff1a\u5e76\u53d1\u8ba1\u6570\u5668\u6570\u7ec4<\/h3>\n\n\n\n
import jdk.internal.vm.annotation.Contended;\n\npublic class ContendedCounterArray {\n\n    static final int SIZE = 4;\n\n    static class Cell {\n        @Contended\n        public volatile long value = 0L;\n    }\n\n    private final Cell[] counters = new Cell[SIZE];\n\n    public ContendedCounterArray() {\n        for (int i = 0; i < SIZE; i++) {\n            counters[i] = new Cell();\n        }\n    }\n\n    public void increment(int index) {\n        counters[index].value++;\n    }\n\n    public long sum() {\n        long total = 0;\n        for (Cell cell : counters) {\n            total += cell.value;\n        }\n        return total;\n    }\n}<\/code><\/pre>\n\n\n\n
\n\n\n\n
\u4e09\u3001\u63a8\u8350\u6784\u5efa\u65b9\u5f0f\uff1a\u5f00\u542f @Contended<\/code> + \u8bbe\u7f6e\u6a21\u5757\u5bfc\u51fa<\/h2>\n\n\n\n
Maven \u6216 Gradle \u542f\u52a8\u53c2\u6570\uff1a<\/h3>\n\n\n\n
--add-exports java.base\/jdk.internal.vm.annotation=ALL-UNNAMED\n-XX:-RestrictContended<\/code><\/pre>\n\n\n\n
\u4e5f\u53ef\u4ee5\u5199\u5165 Maven exec-maven-plugin<\/code>\uff1a<\/p>\n\n\n\n
<plugin>\n  <groupId>org.codehaus.mojo<\/groupId>\n  <artifactId>exec-maven-plugin<\/artifactId>\n  <version>3.1.0<\/version>\n  <configuration>\n    <mainClass>your.main.Class<\/mainClass>\n    <arguments>\n      <argument>-XX:-RestrictContended<\/argument>\n      <argument>--add-exports<\/argument>\n      <argument>java.base\/jdk.internal.vm.annotation=ALL-UNNAMED<\/argument>\n    <\/arguments>\n  <\/configuration>\n<\/plugin><\/code><\/pre>\n\n\n\n
\n\n\n\n
\u56db\u3001\u6700\u4f73\u5b9e\u8df5\u5efa\u8bae\u603b\u7ed3<\/h2>\n\n\n\n
\u9879\u76ee\u5efa\u8bae\u9879<\/th>\u63a8\u8350\u914d\u7f6e \/ \u505a\u6cd5<\/th><\/tr><\/thead>
\u907f\u514d\u4f2a\u5171\u4eab\u7684\u9996\u9009\u65b9\u6848<\/td>\u4f7f\u7528 @Contended<\/code> \u6ce8\u89e3<\/td><\/tr>
\u662f\u5426\u8981\u5f00\u542f JVM \u53c2\u6570<\/td>\u662f\uff0c\u5fc5\u987b -XX:-RestrictContended<\/code><\/td><\/tr>
\u5efa\u8bae\u4f7f\u7528\u4f4d\u7f6e<\/td>volatile<\/code> \u53d8\u91cf\u3001\u7edf\u8ba1\u5b57\u6bb5\u3001\u70ed\u70b9\u5e76\u53d1\u8ba1\u6570\u5668<\/td><\/tr>
\u662f\u5426\u63a8\u8350\u624b\u52a8 padding<\/td>\u4e0d\u63a8\u8350\uff08\u5bb9\u6613\u51fa\u9519\u3001\u96be\u7ef4\u62a4\uff09<\/td><\/tr>
\u662f\u5426\u9002\u5408\u6240\u6709\u573a\u666f<\/td>\u9002\u5408\u9ad8\u5e76\u53d1\u5199\u64cd\u4f5c\u573a\u666f\uff0c\u4e0d\u9002\u7528\u4e8e\u9891\u7e41\u8bfb\u573a\u666f<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
\n\n\n\n
\u4e94\u3001\u63a8\u8350\u66ff\u4ee3\u7c7b\uff1aLongAdder<\/code> \u548c LongAccumulator<\/code><\/h2>\n\n\n\n
\u5982\u679c\u4f60\u53ea\u60f3\u8981\u7ebf\u7a0b\u5b89\u5168\u7684\u9ad8\u6027\u80fd\u52a0\u6cd5\uff0c\u5efa\u8bae\u76f4\u63a5\u4f7f\u7528\uff1a<\/p>\n\n\n\n
LongAdder adder = new LongAdder();\nadder.increment(); \/\/ \u9ad8\u6027\u80fd\nlong total = adder.sum();<\/code><\/pre>\n\n\n\n
\u5b83\u5185\u90e8\u4f7f\u7528\u4e86\u5206\u6bb5 + padding\uff0c\u81ea\u52a8\u907f\u514d\u4f2a\u5171\u4eab\uff0c\u65e0\u9700\u624b\u52a8\u5904\u7406\u3002<\/p>\n\n\n\n
\n\n\n\n
\u516d\u3001\u5b98\u65b9\u53c2\u8003\u8d44\u6599\u4e0e\u94fe\u63a5<\/h2>\n\n\n\n