线程池四种拒绝机制实现及执行日志

news2024/12/23 23:53:19

创建线程池

    public static ExecutorService executor = new ThreadPoolExecutor(2,
            2, 60L, TimeUnit.SECONDS,
            new LinkedBlockingQueue<Runnable>(3), Executors.defaultThreadFactory(),
//            new ThreadPoolExecutor.AbortPolicy()
//     new ThreadPoolExecutor.DiscardPolicy()
            new ThreadPoolExecutor.DiscardOldestPolicy()
//            new ThreadPoolExecutor.CallerRunsPolicy()
    );

测试代码

 @Test
    public void t1() throws InterruptedException {
        for (int i = 0; i < 9; i++) {
            String finalI = i+"";
            try {
                ex(finalI);
            }catch (RejectedExecutionException e){
                System.out.println(finalI+" error = "+e);
                Thread.sleep(2);
                ex(finalI+" 重新执行");
            }

        }
        Thread.sleep(1000*5);
    }

运行线程

 public static void ex(String i) throws RejectedExecutionException{
        String finalI = i;
        executor.execute(new Runnable() {
            private String finalC = finalI;
            @Override
            public void run() {
//                System.out.println(Thread.currentThread().getName()+" == start =="+ finalC);
                try {
                    Thread.sleep(2);
                } catch (InterruptedException e) {
                    System.out.println("error = "+e);
                }
                System.out.println(Thread.currentThread().getName()+" == success =="+ finalC);
            }
        });
    }

全量代码


import org.junit.jupiter.api.Test;

import java.util.concurrent.*;

public class TeTh {
    public static ExecutorService executor = new ThreadPoolExecutor(2,
            2, 60L, TimeUnit.SECONDS,
            new LinkedBlockingQueue<Runnable>(3), Executors.defaultThreadFactory(),
//            new ThreadPoolExecutor.AbortPolicy()
//     new ThreadPoolExecutor.DiscardPolicy()
            new ThreadPoolExecutor.DiscardOldestPolicy()
//            new ThreadPoolExecutor.CallerRunsPolicy()
    );

    @Test
    public void t1() throws InterruptedException {
        for (int i = 0; i < 9; i++) {
            String finalI = i+"";
            try {
                ex(finalI);
            }catch (RejectedExecutionException e){
                System.out.println(finalI+" error = "+e);
                Thread.sleep(2);
                ex(finalI+" 重新执行");
            }

        }
        Thread.sleep(1000*5);
    }
    public static void ex(String i) throws RejectedExecutionException{
        String finalI = i;
        executor.execute(new Runnable() {
            private String finalC = finalI;
            @Override
            public void run() {
//                System.out.println(Thread.currentThread().getName()+" == start =="+ finalC);
                try {
                    Thread.sleep(2);
                } catch (InterruptedException e) {
                    System.out.println("error = "+e);
                }
                System.out.println(Thread.currentThread().getName()+" == success =="+ finalC);
            }
        });
    }
}

日志

AbortPolicy 报出异常模式

5 error = java.util.concurrent.RejectedExecutionException: Task org.cc.automaton.security.TeTh$1@172ed45 rejected from java.util.concurrent.ThreadPoolExecutor@79c292[Running, pool size = 2, active threads = 2, queued tasks = 3, completed tasks = 0]
pool-1-thread-2 == success ==1
pool-1-thread-1 == success ==0
7 error = java.util.concurrent.RejectedExecutionException: Task org.cc.automaton.security.TeTh$1@1574691 rejected from java.util.concurrent.ThreadPoolExecutor@79c292[Running, pool size = 2, active threads = 2, queued tasks = 3, completed tasks = 2]
pool-1-thread-2 == success ==2
pool-1-thread-1 == success ==3
pool-1-thread-2 == success ==4
pool-1-thread-1 == success ==5 重新执行
pool-1-thread-2 == success ==6
pool-1-thread-1 == success ==7 重新执行
pool-1-thread-2 == success ==8

DiscardPolicy 放弃机制啥也不处理

pool-1-thread-1 == success ==0
pool-1-thread-2 == success ==1
pool-1-thread-1 == success ==2
pool-1-thread-2 == success ==3
pool-1-thread-1 == success ==4

DiscardOldestPolicy 放弃机制，放弃列队最早进入的

pool-1-thread-1 == success ==0
pool-1-thread-2 == success ==1
pool-1-thread-1 == success ==6
pool-1-thread-2 == success ==7
pool-1-thread-1 == success ==8

CallerRunsPolicy 交给主线程执行

pool-1-thread-2 == success ==1
pool-1-thread-1 == success ==0
main == success ==5
pool-1-thread-1 == success ==3
main == success ==8
pool-1-thread-2 == success ==2
pool-1-thread-1 == success ==4
pool-1-thread-2 == success ==6
pool-1-thread-1 == success ==7