解决饥饿的问题

git-svn-id: http://code.alibabatech.com/svn/druid/trunk@643 b9813039-fb51-4c41-a8b9-e21c2acb5095

src/main/java/com/alibaba/druid/pool/DruidDataSource.java

@@ -647,8 +647,9 @@ public class DruidDataSource extends DruidAbstractDataSource implements DruidDat
                     // 必须存在线程等待，才创建连接
                     int waitThreadCount = lock.getWaitQueueLength(notEmpty);
 
-                    if (poolingCount - waitThreadCount >= 0) {
-                        empty.await(3, TimeUnit.SECONDS); // 防止信号丢失引起的等待
+                    if (poolingCount >= waitThreadCount) {
+                        notEmpty.signal();
+                        empty.await(); // 防止信号丢失引起的等待
                         continue;
                     }