Java实现的线程池、消息队列功能方法

　ThreadPoolManager类：负责管理线程池，调用轮询的线程来访问字符串缓冲区的内容，维护缓冲区，当线程池溢出时抛出的Runnable任务被加入到字符缓冲区。

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package com.abin.message.line;

import java.util.LinkedList;
import java.util.Queue;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.Executors;
import java.util.concurrent.RejectedExecutionHandler;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

public class ThreadPoolManager {
private static ThreadPoolManager tpm = new ThreadPoolManager();
// 线程池维护线程的最少数量
private final static int CORE_POOL_SIZE = 4;
// 线程池维护线程的最大数量
private final static int MAX_POOL_SIZE = 10;
// 线程池维护线程所允许的空闲时间
private final static int KEEP_ALIVE_TIME = 0;
// 线程池所使用的缓冲队列大小
private final static int WORK_QUEUE_SIZE = 10;
// 消息缓冲队列
Queue msgQueue = new LinkedList();
// 访问消息缓存的调度线程
final Runnable accessBufferThread = new Runnable() {
public void run() {
// 查看是否有待定请求，如果有，则创建一个新的AccessDBThread，并添加到线程池中
if (hasMoreAcquire()) {
String msg = (String) msgQueue.poll();
Runnable task = new AccessDBThread(msg);
threadPool.execute(task);
}
}
};
final RejectedExecutionHandler handler = new RejectedExecutionHandler() {
public void rejectedExecution(Runnable r, ThreadPoolExecutor executor) {
System.out.println(((AccessDBThread) r).getMsg() + "消息放入队列中重新等待执行");
msgQueue.offer(((AccessDBThread) r).getMsg());
}
};
// 管理数据库访问的线程池
final ThreadPoolExecutor threadPool = new ThreadPoolExecutor(
CORE_POOL_SIZE, MAX_POOL_SIZE, KEEP_ALIVE_TIME, TimeUnit.SECONDS,
new ArrayBlockingQueue(WORK_QUEUE_SIZE), this.handler);
// 调度线程池
final ScheduledExecutorService scheduler = Executors
.newScheduledThreadPool(1);
final ScheduledFuture taskHandler = scheduler.scheduleAtFixedRate(
accessBufferThread, 0, 1, TimeUnit.SECONDS);

public static ThreadPoolManager newInstance() {
return tpm;
}

private ThreadPoolManager() {
}

private boolean hasMoreAcquire() {
return !msgQueue.isEmpty();
}

public void addLogMsg(String msg) {
Runnable task = new AccessDBThread(msg);
threadPool.execute(task);
}
}














package com.abin.message.line;

public class AccessDBThread implements Runnable {
private String msg;

public String getMsg() {
return msg;
}

public void setMsg(String msg) {
this.msg = msg;
}

public AccessDBThread() {
super();
}

public AccessDBThread(String msg) {
this.msg = msg;
}

public void run() {
// 向数据库中添加Msg变量值
System.out.println("Added the message: " + msg + " into the Database");
}
}













package com.abin.message.line;

public class TestDriver {
ThreadPoolManager tpm = ThreadPoolManager.newInstance();

public void sendMsg(String msg) {
tpm.addLogMsg(msg + "记录一条日志 ");
}

public static void main(String[] args) {
for (int i = 0; i < 100; i++) {
new TestDriver().sendMsg(Integer.toString(i));
}
}
}