我正在实现一个conenction池(JDBC连接和SMPP连接)。我知道有几个经过良好测试的连接池。但我只是想自己实现。 我在多线程环境中使用它。这更多是我个人的兴趣。我的实现是这样的。 我创建一个ConcurrentLinkedQueue并将连接推送到队列。 每次线程请求连接时,都会从队列中弹出连接。 一旦完成作业,线程就会将连接推送回队列。 我的连接轮询实现类如下所示。
import java.util.concurrent.ConcurrentLinkedQueue;
import org.apache.log4j.Logger;
import org.jsmpp.bean.BindType;
import org.jsmpp.bean.NumberingPlanIndicator;
import org.jsmpp.bean.TypeOfNumber;
import org.jsmpp.session.BindParameter;
import org.jsmpp.session.SMPPSession;
public class SMPPConnectionPool {
static ConcurrentLinkedQueue<SMPPSession> connectionPool = null;
static Logger LOG = null;
static
{
LOG = LogManager.getLogger(SMPPConnectionPool.class);
connectionPool= new ConcurrentLinkedQueue<SMPPSession>();
}
/* This method returns session from queue .If no sessions exist in the queue,then a new session will be created and returned.
* This method use QueryGparams APi to read conenction related data from gparams
* */
public static SMPPSession getConenction()
{
SMPPSession session=connectionPool.poll();
if(session!=null)
{
System.out.println("Thread "+Thread.currentThread().getName() +" got "+session.getSessionId());
LOG.info("Thread "+Thread.currentThread().getName() +" got "+session.getSessionId());
return session;
}
else
{
SMPPSession smppSession = new SMPPSession();
try {
String host = QueryGparams.getGparamAsString(NotificationConstants.SMSC_HOST);
int port = QueryGparams.getGparamAsInteger(NotificationConstants.SMSC_PORT);
String systemId = QueryGparams.getGparamAsString(NotificationConstants.SMSC_SYSTEM_ID);
String password = QueryGparams.getGparamAsString(NotificationConstants.SMSC_PASSWORD);
if(host == null || systemId == null || password == null || port == 0)
{
String errorMessage = "Following parameters are null \n";
if(host == null) {
errorMessage = errorMessage + "host is null";
}
if(systemId == null) {
errorMessage = errorMessage + "systemId is null";
}
if(password == null) {
errorMessage = errorMessage + "password is null";
}
if(port == 0) { //TODO Need to change this if QueryGParams API will not return zero when port number is not specified
errorMessage = errorMessage + "port is null";
}
throw new Exception(errorMessage);
}
smppSession
.connectAndBind(host,port, new BindParameter(
BindType.BIND_TRX, systemId,
password, "",
TypeOfNumber.UNKNOWN,
NumberingPlanIndicator.UNKNOWN, null));
LOG.info("Session has been created.Session id is "+smppSession.getSessionId());
} catch (Exception e) {
LOG.error(CommonUtilities.getExceptionString(e));
}
System.out.println("Thread "+Thread.currentThread().getName() +" got "+smppSession.getSessionId());
LOG.info("Thread "+Thread.currentThread().getName() +" got "+smppSession.getSessionId());
return smppSession;
}
}
//This method pushes conenction back to queue ,to make it available for other threads.
public static void pushConenction(SMPPSession smppSession)
{
boolean isInserted=connectionPool.offer(smppSession);
if(isInserted)
{
LOG.info("Pushed the conenction back to queue");
System.out.println("Pushed the conenction back to queue");
}
else
{
LOG.info("Failed to push the session back to queue");
System.out.println("Failed to push the session back to queue");
}
}
public static void closeSessions()
{
while(connectionPool!=null && connectionPool.size()>0)
{
SMPPSession session=connectionPool.poll();
session.unbindAndClose();
LOG.info("Closed the session");
}
}
}
我只是想知道这个实现的问题。请咨询。我想为JDBC连接池实现做同样的事情
答案 0 :(得分:0)
1)boolean isInserted = connectionPool.offer(smppSession);并且随后的分析没有意义,因为ConcurrentLinkedQueue是无界的,它的offer()总是返回true。请参阅API
2)如果达到最大活动threds,我会使用BlockingQueue并让线程等待活动线程返回到池的连接
3)我会以这种方式初始化静态字段
static ConcurrentLinkedQueue<SMPPSession> connectionPool = new ConcurrentLinkedQueue<SMPPSession>();
static Logger LOG = LogManager.getLogger(SMPPConnectionPool.class);
4)为了避免不必要的字符串连接,你可以使用这个习语
if (LOG.isInfoEnabled()) {
LOG.info("Thread "+Thread.currentThread().getName() +" got "+smppSession.getSessionId());
}
5)这似乎很可疑
} catch (Exception e) {
LOG.error(CommonUtilities.getExceptionString(e));
}
System.out.println("Thread "+Thread.currentThread().getName() +" got "+smppSession.getSessionId());
你捕获异常并继续,好像一切正常
答案 1 :(得分:0)
我在实现中看到的一些问题如下:
没有为connectAndBind配置超时。在网络分区或数据包丢失的情况下,getConnection调用很可能会被卡住。
如果网络中断,数据源与客户端之间的TCP连接可能会中断。因此,池所保持的连接将是陈旧的。似乎没有机制可以“刷新”连接。许多连接池框架提供了testConnections,可以在后台执行,也可以在签出连接之前执行(这当然会增加整个getConnection调用的延迟),以应对这种情况。