概述
高并发编程-自定义简易的线程池（1），体会原理 中只实现了任务队列，我们这里把其余的几个也补充进来
- 拒绝策略
- 关闭线程池
- 最小 最大 活动线程数
- …
示例
比较简单，直接上代码，见注释
package com.artisan.test;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
public class SimpleThreadPool extends Thread {
// 线程数
private int size;
// 队列大小
private final int queueSize;
// 默认队列大小
private final static int DEFAULT_TASK_QUEUE_SIZE = 2000;
// 工作线程相关属性
private static volatile int seq = 0;
private final static String THREAD_PREFIX = "SIMPLE_THREAD_POOL-";
private final static ThreadGroup GROUP = new ThreadGroup("Pool_Group");
// 任务队列
private final static LinkedList<Runnable> TASK_QUEUE = new LinkedList<>();
// 线程队列
private final static List<WorkerTask> THREAD_QUEUE = new ArrayList<>();
// 拒绝策略
private final DiscardPolicy discardPolicy;
// 默认拒绝策略
public final static DiscardPolicy DEFAULT_DISCARD_POLICY = () -> {
throw new DiscardException("Discard This Task.");
};
//是否销毁
private volatile boolean destroy = false;
// 最小线程数
private int min;
// 最大线程数
private int max;
// 活动线程数
private int active;
/**
* 默认无参构造函数
*/
public SimpleThreadPool() {
// 调用有参构造函数
this(4, 8, 12, DEFAULT_TASK_QUEUE_SIZE, DEFAULT_DISCARD_POLICY);
}
/**
* 构造函数
* @param min
* @param active
* @param max
* @param queueSize
* @param discardPolicy
*/
public SimpleThreadPool(int min, int active, int max, int queueSize, DiscardPolicy discardPolicy) {
this.min = min;
this.active = active;
this.max = max;
this.queueSize = queueSize;
this.discardPolicy = discardPolicy;
init();
}
/**
* 初始化方法
*/
private void init() {
for (int i = 0; i < this.min; i++) {
//
createWorkTask();
}
this.size = min;
this.start();
}
/**
* 提交任务到 TASK_QUEUE
* @param runnable
*/
public void submit(Runnable runnable) {
if (destroy)
throw new IllegalStateException("The thread pool already destroy and not allow submit task.");
synchronized (TASK_QUEUE) {
if (TASK_QUEUE.size() > queueSize)
discardPolicy.discard();
TASK_QUEUE.addLast(runnable);
TASK_QUEUE.notifyAll();
}
}
/**
* 管理线程池本身的参数
*/
@Override
public void run() {
while (!destroy) {
System.out.printf("Pool#Min:%d,Active:%d,Max:%d,Current:%d,QueueSize:%d\n",
this.min, this.active, this.max, this.size, TASK_QUEUE.size());
try {
Thread.sleep(5_000L);
if (TASK_QUEUE.size() > active && size < active) {
for (int i = size; i < active; i++) {
createWorkTask();
}
System.out.println("The pool incremented to active.");
size = active;
} else if (TASK_QUEUE.size() > max && size < max) {
for (int i = size; i < max; i++) {
createWorkTask();
}
System.out.println("The pool incremented to max.");
size = max;
}
synchronized (THREAD_QUEUE) {
if (TASK_QUEUE.isEmpty() && size > active) {
System.out.println("=========Reduce========");
int releaseSize = size - active;
for (Iterator<WorkerTask> it = THREAD_QUEUE.iterator(); it.hasNext(); ) {
if (releaseSize <= 0)
break;
WorkerTask task = it.next();
task.close();
task.interrupt();
it.remove();
releaseSize--;
}
size = active;
}
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
/**
* 创建工作线程
*/
private void createWorkTask() {
WorkerTask task = new WorkerTask(GROUP, THREAD_PREFIX + (seq++));
task.start();
THREAD_QUEUE.add(task);
}
/**
* 关闭线程池
* @throws InterruptedException
*/
public void shutdown() throws InterruptedException {
while (!TASK_QUEUE.isEmpty()) {
Thread.sleep(50);
}
synchronized (THREAD_QUEUE) {
int initVal = THREAD_QUEUE.size();
while (initVal > 0) {
for (WorkerTask task : THREAD_QUEUE) {
if (task.getTaskState() == TaskState.BLOCKED) {
task.interrupt();
task.close();
initVal--;
} else {
Thread.sleep(10);
}
}
}
}
System.out.println(GROUP.activeCount());
this.destroy = true;
System.out.println("The thread pool disposed.");
}
public int getQueueSize() {
return queueSize;
}
public int getSize() {
return size;
}
public boolean isDestroy() {
return this.destroy;
}
public int getMin() {
return min;
}
public int getMax() {
return max;
}
public int getActive() {
return active;
}
/**
* 工作线程的状态
*/
private enum TaskState {
FREE, RUNNING, BLOCKED, DEAD
}
/**
* 触发决绝策略抛出的异常
*/
public static class DiscardException extends RuntimeException {
public DiscardException(String message) {
super(message);
}
}
/**
* 拒绝策略接口
*/
public interface DiscardPolicy {
void discard() throws DiscardException;
}
/**
* 工作线程
*/
private static class WorkerTask extends Thread {
private volatile TaskState taskState = TaskState.FREE;
public WorkerTask(ThreadGroup group, String name) {
super(group, name);
}
public TaskState getTaskState() {
return this.taskState;
}
public void run() {
OUTER:
while (this.taskState != TaskState.DEAD) {
Runnable runnable;
synchronized (TASK_QUEUE) {
while (TASK_QUEUE.isEmpty()) {
try {
taskState = TaskState.BLOCKED;
TASK_QUEUE.wait();
} catch (InterruptedException e) {
System.out.println("Closed.");
break OUTER;
}
}
runnable = TASK_QUEUE.removeFirst();
}
if (runnable != null) {
taskState = TaskState.RUNNING;
runnable.run();
taskState = TaskState.FREE;
}
}
}
/**
* 关闭
*/
public void close() {
this.taskState = TaskState.DEAD;
}
}
/**
* 测试
* @param args
* @throws InterruptedException
*/
public static void main(String[] args) throws InterruptedException {
SimpleThreadPool threadPool = new SimpleThreadPool();
for (int i = 0; i < 40; i++) {
threadPool.submit(() -> {
System.out.println("The runnable be serviced by " + Thread.currentThread() + " start.");
try {
Thread.sleep(3000);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("The runnable be serviced by " + Thread.currentThread() + " finished.");
});
}
Thread.sleep(10000);
threadPool.shutdown();
/* Thread.sleep(10000);
threadPool.shutdown();
threadPool.submit(() -> System.out.println("======="));*/
}
}
运行日志：
"E:\Program Files\Java\jdk1.8.0_161\bin\java" "-javaagent:E:\Program Files\JetBrains\IntelliJ IDEA 2017.2.4\lib\idea_rt.jar=53638:E:\Program Files\JetBrains\IntelliJ IDEA 2017.2.4\bin" -Dfile.encoding=UTF-8 -classpath "E:\Program Files\Java\jdk1.8.0_161\jre\lib\charsets.jar;E:\Program Files\Java\jdk1.8.0_161\jre\lib\deploy.jar;E:\Program Files\Java\jdk1.8.0_161\jre\lib\ext\access-bridge-64.jar;E:\Program Files\Java\jdk1.8.0_161\jre\lib\ext\cldrdata.jar;E:\Program Files\Java\jdk1.8.0_161\jre\lib\ext\dnsns.jar;E:\Program Files\Java\jdk1.8.0_161\jre\lib\ext\jaccess.jar;E:\Program Files\Java\jdk1.8.0_161\jre\lib\ext\jfxrt.jar;E:\Program Files\Java\jdk1.8.0_161\jre\lib\ext\localedata.jar;E:\Program Files\Java\jdk1.8.0_161\jre\lib\ext\nashorn.jar;E:\Program Files\Java\jdk1.8.0_161\jre\lib\ext\sunec.jar;E:\Program Files\Java\jdk1.8.0_161\jre\lib\ext\sunjce_provider.jar;E:\Program Files\Java\jdk1.8.0_161\jre\lib\ext\sunmscapi.jar;E:\Program Files\Java\jdk1.8.0_161\jre\lib\ext\sunpkcs11.jar;E:\Program Files\Java\jdk1.8.0_161\jre\lib\ext\zipfs.jar;E:\Program Files\Java\jdk1.8.0_161\jre\lib\javaws.jar;E:\Program Files\Java\jdk1.8.0_161\jre\lib\jce.jar;E:\Program Files\Java\jdk1.8.0_161\jre\lib\jfr.jar;E:\Program Files\Java\jdk1.8.0_161\jre\lib\jfxswt.jar;E:\Program Files\Java\jdk1.8.0_161\jre\lib\jsse.jar;E:\Program Files\Java\jdk1.8.0_161\jre\lib\management-agent.jar;E:\Program Files\Java\jdk1.8.0_161\jre\lib\plugin.jar;E:\Program Files\Java\jdk1.8.0_161\jre\lib\resources.jar;E:\Program Files\Java\jdk1.8.0_161\jre\lib\rt.jar;D:\IdeaProjects\mvc\target\classes" com.artisan.test.SimpleThreadPool
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-0,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-2,5,Pool_Group] start.
Pool#Min:4,Active:8,Max:12,Current:4,QueueSize:38
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-1,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-3,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-2,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-0,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-2,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-0,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-3,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-1,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-3,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-1,5,Pool_Group] start.
The pool incremented to active.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-4,5,Pool_Group] start.
Pool#Min:4,Active:8,Max:12,Current:8,QueueSize:31
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-5,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-6,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-7,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-2,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-0,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-2,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-0,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-3,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-1,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-1,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-3,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-4,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-4,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-7,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-7,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-5,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-6,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-5,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-6,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-2,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-0,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-0,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-2,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-3,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-1,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-3,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-1,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-8,5,Pool_Group] start.
The pool incremented to max.
Pool#Min:4,Active:8,Max:12,Current:12,QueueSize:15
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-9,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-10,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-11,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-4,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-4,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-7,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-7,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-6,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-5,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-6,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-5,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-0,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-0,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-2,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-2,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-3,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-1,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-3,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-1,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-8,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-9,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-8,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-9,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-10,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-11,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-10,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-11,5,Pool_Group] start.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-4,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-7,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-6,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-5,5,Pool_Group] finished.
Closed.
Closed.
Closed.
Closed.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-0,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-2,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-1,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-3,5,Pool_Group] finished.
Closed.
Closed.
Closed.
Closed.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-8,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-10,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-11,5,Pool_Group] finished.
The runnable be serviced by Thread[SIMPLE_THREAD_POOL-9,5,Pool_Group] finished.
Closed.
4
=========Reduce========
The thread pool disposed.
Closed.
Closed.
Closed.
Process finished with exit code 0
本文标题：高并发编程-自定义简易的线程池（2），体会原理
本文链接：https://blog.quwenai.cn/post/6327.html
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