ThreadPoolManager類：負責管理線程池，調用輪詢的線程來訪問字符串緩衝區的內容，維護緩衝區，當線程池溢出時拋出的Runnable任務被加入到字符緩衝區。
public class ThreadPoolManager
{
private static ThreadPoolManager tpm = new ThreadPoolManager();
// 線程池維護線程的最少數量
private final static int CORE_POOL_SIZE = 4;
// 線程池維護線程的最大數量
private final static int MAX_POOL_SIZE = 10;
// 線程池維護線程所允許的空閒時間
private final static int KEEP_ALIVE_TIME = 0;
// 線程池所使用的緩衝隊列大小
private final static int WORK_QUEUE_SIZE = 10;
// 消息緩衝隊列
Queue msgQueue = new LinkedList();
// 訪問消息緩存的調度線程
final Runnable accessBufferThread = new Runnable()
{
public void run()
{
// 查看是否有待定請求，如果有，則創建一個新的AccessDBThread，並添加到線程池中
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()+"消息放入隊列中重新等待執行");
msgQueue.offer((( AccessDBThread ) r ).getMsg() );
}
};
// 管理數據庫訪問的線程池
final ThreadPoolExecutor threadPool = new ThreadPoolExecutor(
CORE_POOL_SIZE, MAX_POOL_SIZE, KEEP_ALIVE_TIME, TimeUnit.SECONDS,
new ArrayBlockingQueue( WORK_QUEUE_SIZE ), this.handler );
// 調度線程池
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 );
}
}
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()
{
// 向數據庫中添加Msg變量值
System.out.println("Added the message: "+msg+" into the Database");
}
}
public class TestDriver
{
ThreadPoolManager tpm = ThreadPoolManager.newInstance();
public void sendMsg( String msg )
{
tpm.addLogMsg( msg + "記錄一條日誌 " );
}
public static void main( String[] args )
{
for( int i = 0; i <100; i++ )
{
new TestDriver().sendMsg( Integer.toString( i ) );