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了解更多学习 ThreadPoolExecutor 类
ThreadPool.java
package com.tool.me.thread;
import java.util.Hashtable;
import java.util.Map;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
public class ThreadPool {
private static Map<String, ThreadPoolExecutor> map = new Hashtable<>();
private ThreadPoolExecutor executor;
/**
* 阻塞任务队列数
*/
private int wattingCount;
/**
* 线程池的名字，e.g: 子系统的包名 (com.tool.me)
*/
@SuppressWarnings(“unused”)
private String name;
/**
* 创建线程池
*
* @param name
* 线程池的名字，eg: 子系统的包名 (com.tool.me)
* @param corePoolSize
* 核心线程池大小 the number of threads to keep in the pool, even if
* they are idle, unless {@code allowCoreThreadTimeOut} is set
* @param maximumPoolSize
* 最大线程池大小 the maximum number of threads to allow in the pool
* @param keepAliveTime
* 线程池中超过 corePoolSize 数目的空闲线程最大存活时间 when the number of threads is
* greater than the core, this is the maximum time that excess
* idle threads will wait for new tasks before terminating.
* @param unit
* keepAliveTime 时间单位 the time unit for the {@code keepAliveTime}
* argument
* @param workQueue
* 阻塞任务队列 the queue to use for holding tasks before they are
* executed. This queue will hold only the {@code Runnable} tasks
* submitted by the {@code execute} method.
*/
public ThreadPool(String name, int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit,
BlockingQueue<Runnable> workQueue) {
synchronized (map) {
this.name = name;
this.wattingCount = workQueue.size();
String key = buildKey(name, corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue.size(), “#”);
if (map.containsKey(key)) {
executor = map.get(key);
} else {
executor = new ThreadPoolExecutor(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue);
map.put(key, executor);
}
}
}
/**
* 创建线程池
*
* @param name
* 线程池的名字，eg: 子系统的包名 (com.tool.me)
* @param corePoolSize
* 核心线程池大小 the number of threads to keep in the pool, even if
* they are idle, unless {@code allowCoreThreadTimeOut} is set
* @param maximumPoolSize
* 最大线程池大小 the maximum number of threads to allow in the pool
* @param keepAliveTime
* 线程池中超过 corePoolSize 数目的空闲线程最大存活时间 when the number of threads is
* greater than the core, this is the maximum time that excess
* idle threads will wait for new tasks before terminating.
* @param unit
* keepAliveTime 时间单位 the time unit for the {@code keepAliveTime}
* argument
* @param wattingCount
* 阻塞任务队列数
*/
public ThreadPool(String name, int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit,
int wattingCount) {
synchronized (map) {
this.name = name;
this.wattingCount = (int) (wattingCount * 1.5);
String key = buildKey(name, corePoolSize, maximumPoolSize, keepAliveTime, unit, wattingCount, “#”);
if (map.containsKey(key)) {
executor = map.get(key);
} else {
executor = new ThreadPoolExecutor(corePoolSize, maximumPoolSize, keepAliveTime, unit,
new LinkedBlockingQueue<Runnable>(this.wattingCount));
map.put(key, executor);
}
}
}
/**
* 组装 map 中的 key
*
* @param name
* 线程池的名字，eg: 子系统的包名 (com.tool.me)
* @param corePoolSize
* 核心线程池大小 the number of threads to keep in the pool, even if
* they are idle, unless {@code allowCoreThreadTimeOut} is set
* @param maximumPoolSize
* 最大线程池大小 the maximum number of threads to allow in the pool
* @param keepAliveTime
* 线程池中超过 corePoolSize 数目的空闲线程最大存活时间 when the number of threads is
* greater than the core, this is the maximum time that excess
* idle threads will wait for new tasks before terminating.
* @param unit
* keepAliveTime 时间单位 the time unit for the {@code keepAliveTime}
* argument
* @param workQueue
* 阻塞任务队列 the queue to use for holding tasks before they are
* executed. This queue will hold only the {@code Runnable} tasks
* submitted by the {@code execute} method.
* @param delimiter
* 分割符
*/
private String buildKey(String name, int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit,
int wattingCount, String delimiter) {
StringBuilder result = new StringBuilder();
result.append(name).append(delimiter);
result.append(corePoolSize).append(delimiter);
result.append(maximumPoolSize).append(delimiter);
result.append(keepAliveTime).append(delimiter);
result.append(unit.toString()).append(delimiter);
result.append(wattingCount);
return result.toString();
}
/**
* 添加任务到线程池（execute）中
* @param runnable the task to execute
*/
public void execute(Runnable runnable) {
checkQueneSize();
executor.execute(runnable);
}
private void checkQueneSize() {
while (getTaskSzie() >= wattingCount) {// 如果线程池中的阻塞队列数 > wattingCount 则继续等待
try {
Thread.sleep(100);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
/**
* Returns the number of elements in this collection. If this collection
* contains more than <tt>Integer.MAX_VALUE</tt> elements, returns
* <tt>Integer.MAX_VALUE</tt>.
*
* @return the number of elements in this collection
*/
public int getTaskSzie(){
return executor.getQueue().size();
}
}
ThreadPoolManager.java
package com.tool.me.thread;
import java.util.concurrent.TimeUnit;
public abstract class ThreadPoolManager {
private ThreadPool executor = null;
public ThreadPoolManager() {
if(executor == null) {
executor = new ThreadPool(getThreadPoolName(),corePoolSize(), maximumPoolSize(), keepAliveTime(), TimeUnit.SECONDS, wattingCount());
}
}
public void execute(Runnable runnable) {
executor.execute(runnable);
}
/**
* @return name
* 线程池名称 the String of pool name
*/
protected abstract String getThreadPoolName();
/**
* @return corePoolSize
* 核心线程池大小 the number of threads to keep in the pool, even if
* they are idle, unless {@code allowCoreThreadTimeOut} is set
*/
protected int corePoolSize(){
return 5;
}
/**
* @return maximumPoolSize
* 最大线程池大小 the maximum number of threads to allow in the pool
*/
protected int maximumPoolSize(){
return 10;
}
/**
* @return wattingCount
* 阻塞任务队列数
*/
protected int wattingCount(){
return 200000;
}
/**
* @return keepAliveTime
* 线程池中超过 corePoolSize 数目的空闲线程最大存活时间 when the number of threads is
* greater than the core, this is the maximum time that excess
* idle threads will wait for new tasks before terminating.
*/
protected long keepAliveTime(){
return 10;
}
}
子系统创建类 继承 ThreadPoolManager，配置参数信息 ViThreadPoolManager.java
package com.tool.me.thread;
/**
* 当前类（子系统中定义的类）继承 ThreadPoolManager 类，设置相关参数
*/
public class ViThreadPoolManager extends ThreadPoolManager{
private static ThreadPoolManager threadPool = null;
public synchronized static ThreadPoolManager getInstance() {
if(threadPool == null) {
threadPool = new ViThreadPoolManager();
}
return threadPool;
}
@Override
protected String getThreadPoolName() {
return “com.tool.me.vi”;
}
@Override
protected int corePoolSize() {
/**
* 代码 设置返回值
*/
return 10;
}
@Override
protected int maximumPoolSize() {
/**
* 代码 设置返回值
*/
return 20;
}
}
使用线程池 main
public static void main(String[] args) {
ViThreadPoolManager.getInstance().execute(new Runnable() {
@Override
public void run() {
io();
}
});
}