項目目錄結構

HighConcurrencyTimerProject/
├── src/
│   ├── main/
│   │   ├── java/
│   │   │   ├── com/
│   │   │   │   ├── example/
│   │   │   │   │   ├── HighConcurrencyTimerExample.java
│   │   │   │   │   ├── ThreadPoolExample.java
│   ├── test/
│   │   ├── java/
│   │   │   ├── com/
│   │   │   │   ├── example/
│   │   │   │   │   ├── HighConcurrencyTimerExampleTest.java
│   │   │   │   │   ├── ThreadPoolExampleTest.java
├── pom.xmlHighConcurrencyTimerProject/
├── src/
│   ├── main/
│   │   ├── java/
│   │   │   ├── com/
│   │   │   │   ├── example/
│   │   │   │   │   ├── HighConcurrencyTimerExample.java
│   │   │   │   │   ├── ThreadPoolExample.java
│   ├── test/
│   │   ├── java/
│   │   │   ├── com/
│   │   │   │   ├── example/
│   │   │   │   │   ├── HighConcurrencyTimerExampleTest.java
│   │   │   │   │   ├── ThreadPoolExampleTest.java
├── pom.xml

代碼文件

HighConcurrencyTimerExample.java

package com.example;

import io.netty.util.HashedWheelTimer;
import io.netty.util.Timeout;
import io.netty.util.TimerTask;

import java.util.concurrent.TimeUnit;

public class HighConcurrencyTimerExample {
    public static void main(String[] args) {
        // 創建一個HashedWheelTimer實例，時間輪的精度為1毫秒，槽數為1024
        HashedWheelTimer timer = new HashedWheelTimer(1, TimeUnit.MILLISECONDS, 1024);

        // 創建並添加100萬個定時任務
        for (int i = 0; i < 1000000; i++) {
            timer.newTimeout(new TimerTask() {
                @Override
                public void run(Timeout timeout) {
                    System.out.println("Task executed at: " + new java.util.Date());
                }
            }, 1, TimeUnit.SECONDS);
        }

        // 關閉定時器
        Runtime.getRuntime().addShutdownHook(new Thread(timer::stop));
    }
}

ThreadPoolExample.java

package com.example;

import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

public class ThreadPoolExample {
    public static void main(String[] args) {
        ScheduledExecutorService executorService = Executors.newScheduledThreadPool(10);
        for (int i = 0; i < 1000000; i++) {
            executorService.schedule(() -> System.out.println("Task executed at: " + new java.util.Date()), 1, TimeUnit.SECONDS);
        }
        executorService.shutdown();
    }
}

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.example</groupId>
    <artifactId>HighConcurrencyTimerProject</artifactId>
    <version>1.0-SNAPSHOT</version>
    <dependencies>
        <dependency>
            <groupId>io.netty</groupId>
            <artifactId>netty-all</artifactId>
            <version>4.1.68.Final</version>
        </dependency>
    </dependencies>
</project>

構建項目

• 打開終端，導航到項目根目錄，運行以下命令來構建項目：

mvn clean install

運行項目：

• 使用以下命令運行 HighConcurrencyTimerExample：

mvn exec:java -Dexec.mainClass="com.example.HighConcurrencyTimerExample"

當你運行 HighConcurrencyTimerExample 時，控制枱會每秒輸出大量任務執行的時間戳。例如：

Task executed at: Fri Dec 27 22:10:00 CST 2024
Task executed at: Fri Dec 27 22:10:00 CST 2024
Task executed at: Fri Dec 27 22:10:00 CST 2024
...

• 使用以下命令運行 ThreadPoolExample：

mvn exec:java -Dexec.mainClass="com.example.ThreadPoolExample"

當你運行 ThreadPoolExample 時，控制枱也會每秒輸出大量任務執行的時間戳。例如：

Task executed at: Fri Dec 27 22:10:00 CST 2024
Task executed at: Fri Dec 27 22:10:00 CST 2024
Task executed at: Fri Dec 27 22:10:00 CST 2024
...