手写自旋锁
commit
507f7c7275
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target/
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!.mvn/wrapper/maven-wrapper.jar
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!**/src/main/**/target/
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!**/src/test/**/target/
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### IntelliJ IDEA ###
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.idea/modules.xml
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.idea/jarRepositories.xml
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.idea/compiler.xml
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.idea/libraries/
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*.iws
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*.iml
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*.ipr
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### Eclipse ###
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.apt_generated
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.classpath
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.factorypath
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.project
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.settings
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.springBeans
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.sts4-cache
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### NetBeans ###
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/nbproject/private/
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/nbbuild/
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/dist/
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/nbdist/
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/.nb-gradle/
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build/
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!**/src/main/**/build/
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!**/src/test/**/build/
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### VS Code ###
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.vscode/
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### Mac OS ###
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.DS_Store
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# 默认忽略的文件
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/shelf/
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/workspace.xml
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# 基于编辑器的 HTTP 客户端请求
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/httpRequests/
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# Datasource local storage ignored files
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/dataSources/
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/dataSources.local.xml
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<?xml version="1.0" encoding="UTF-8"?>
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<project version="4">
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<component name="Encoding">
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<file url="file://$PROJECT_DIR$/src/main/java" charset="UTF-8" />
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<file url="file://$PROJECT_DIR$/src/main/resources" charset="UTF-8" />
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</component>
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</project>
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<?xml version="1.0" encoding="UTF-8"?>
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<project version="4">
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<component name="ExternalStorageConfigurationManager" enabled="true" />
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<component name="MavenProjectsManager">
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<option name="originalFiles">
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<list>
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<option value="$PROJECT_DIR$/pom.xml" />
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</list>
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</option>
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</component>
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<component name="ProjectRootManager" version="2" languageLevel="JDK_17" default="true" project-jdk-name="17" project-jdk-type="JavaSDK">
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<output url="file://$PROJECT_DIR$/out" />
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</component>
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</project>
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<?xml version="1.0" encoding="UTF-8"?>
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<project version="4">
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<component name="VcsDirectoryMappings">
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<mapping directory="$PROJECT_DIR$" vcs="Git" />
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</component>
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</project>
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<?xml version="1.0" encoding="UTF-8"?>
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<project xmlns="http://maven.apache.org/POM/4.0.0"
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xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
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xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
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<modelVersion>4.0.0</modelVersion>
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<groupId>org.example</groupId>
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<artifactId>weekly</artifactId>
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<version>1.0-SNAPSHOT</version>
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<properties>
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<maven.compiler.source>17</maven.compiler.source>
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<maven.compiler.target>17</maven.compiler.target>
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<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
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</properties>
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</project>
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package org.example;
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import java.util.concurrent.TimeUnit;
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import java.util.concurrent.atomic.AtomicReference;
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public class Main {
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AtomicReference<Thread> atomicReference = new AtomicReference<>();
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public void lock() {
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Thread threadA = Thread.currentThread();
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//假如线程A先进入锁
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System.out.printf(Thread.currentThread().getName() + "\t" + "----------come in"+"\n");
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while (!atomicReference.compareAndSet(null, threadA)) {
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//期望值为null 更新值为线程A自己
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//线程A持有锁成功
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}
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}
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public void unlock() {
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Thread threadA = Thread.currentThread();
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//线程A肯定希望出来的是自己,线程A一走锁就空了
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//使用期望值为线程A自己 更新值为null
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atomicReference.compareAndSet(threadA, null);
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System.out.printf(Thread.currentThread().getName() + "\t" + "----------task over,unlock"+"\n");
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}
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public static void main(String[] args) {
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Main main = new Main();
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new Thread(() -> {
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main.lock();
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//暂停几秒钟线程
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try {TimeUnit.SECONDS.sleep(5);} catch (InterruptedException e) {e.printStackTrace();}
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main.unlock();
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}, "A").start();
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//线程A先于线程B启动
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try {TimeUnit.MILLISECONDS.sleep(500);} catch (InterruptedException e) {e.printStackTrace();}
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new Thread(() -> {
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main.lock();
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main.unlock();
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}, "B").start();
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}
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}
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Loading…
Reference in New Issue