執行程序ThreadPool，垃圾回收

Question

我正在使用ThreadPool執行程序在do while循環中作爲deamon進程。我在創建新的固定線程池： executor = Executors.newFixedThreadPool（5）;

任務完成後，我在下一次迭代開始前調用shutdown，併爲new 5 worker線程創建newFixedPool。

現在打印Log4J日誌。我正在使用[％t]來顯示執行哪個線程池。 我看到每個迭代新線程池獲得創建一個遞增的數字。

請讓我知道在開始下一次迭代之前，我需要調用executor = null嗎？

遞增的線程池指示線程池獲取累積並可能導致內存泄漏，因爲它是一個deamon進程或在後端線程池將被垃圾收集，因爲所有線程都已完成並且我們已經執行了關閉。

2014-06-26 16:26:11,548 [47 ] [INFO ][pool-1-thread-1] - Started processing new   payments for serverID: 5 
2014-06-26 16:26:11,548 [47 ] [INFO ][pool-1-thread-2] - Started processing new payments for serverID: 6 
2014-06-26 16:26:11,548 [47 ] [INFO ][pool-1-thread-3] - Started processing new payments for serverID: 7 
2014-06-26 16:26:11,548 [47 ] [INFO ][pool-1-thread-4] - Started processing new payments for serverID: 8 
2014-06-26 16:26:11,548 [47 ] [INFO ][pool-1-thread-5] - Started processing new payments for serverID: 9 
2014-06-26 16:26:24,129 [12628 ] [INFO ][pool-1-thread-2] - Completed processing new payments for serverID: 6 
2014-06-26 16:26:24,129 [12628 ] [INFO ][pool-1-thread-5] - Completed processing new payments for serverID: 9 
2014-06-26 16:26:24,129 [12628 ] [INFO ][pool-1-thread-2] - Time taken to Process new payments for serverId 6 : 12 Sec 
2014-06-26 16:26:24,129 [12628 ] [INFO ][pool-1-thread-5] - Time taken to Process new payments for serverId 9 : 12 Sec 
2014-06-26 16:26:24,129 [12628 ] [INFO ][pool-1-thread-3] - Completed processing new payments for serverID: 7 
2014-06-26 16:26:24,129 [12628 ] [INFO ][pool-1-thread-1] - Completed processing new payments for serverID: 5 
2014-06-26 16:26:24,129 [12628 ] [INFO ][pool-1-thread-3] - Time taken to Process new payments for serverId 7 : 12 Sec 
2014-06-26 16:26:24,129 [12628 ] [INFO ][pool-1-thread-1] - Time taken to Process new payments for serverId 5 : 12 Sec 
2014-06-26 16:26:24,129 [12628 ] [INFO ][pool-1-thread-4] - Completed processing new payments for serverID: 8 
2014-06-26 16:26:24,129 [12628 ] [INFO ][pool-1-thread-4] - Time taken to Process new payments for serverId 8 : 12 Sec 
2014-06-26 16:26:24,129 [12628 ] [INFO ][main] - ShutDown complete 
2014-06-26 16:26:24,129 [12628 ] [INFO ][main] - ProcessDeamon iteration finished in 0 Sec 
2014-06-26 16:26:24,129 [12628 ] [INFO ][main] - ProcessDeamon iteration started 
2014-06-26 16:26:24,191 [12690 ] [INFO ][pool-2-thread-1] - Started processing new payments for serverID: 5 
2014-06-26 16:26:24,191 [12690 ] [INFO ][pool-2-thread-2] - Started processing new payments for serverID: 6 
2014-06-26 16:26:24,191 [12690 ] [INFO ][pool-2-thread-3] - Started processing new payments for serverID: 7 
2014-06-26 16:26:24,191 [12690 ] [INFO ][pool-2-thread-4] - Started processing new payments for serverID: 8 
2014-06-26 16:26:24,191 [12690 ] [INFO ][pool-2-thread-5] - Started processing new payments for serverID: 9 

2014-06-26 16:26:34,443 [22942 ] [INFO ][pool-2-thread-2] - Completed processing new payments for serverID: 6 
2014-06-26 16:26:34,443 [22942 ] [INFO ][pool-2-thread-2] - Time taken to Process new payments for serverId 6 : 10 Sec 
2014-06-26 16:26:34,490 [22989 ] [INFO ][pool-2-thread-4] - Completed processing new payments for serverID: 8 
2014-06-26 16:26:34,490 [22989 ] [INFO ][pool-2-thread-3] - Completed processing new payments for serverID: 7 
2014-06-26 16:26:34,490 [22989 ] [INFO ][pool-2-thread-5] - Completed processing new payments for serverID: 9 
2014-06-26 16:26:34,490 [22989 ] [INFO ][pool-2-thread-4] - Time taken to Process new payments for serverId 8 : 10 Sec 
2014-06-26 16:26:34,490 [22989 ] [INFO ][pool-2-thread-3] - Time taken to Process new payments for serverId 7 : 10 Sec 
2014-06-26 16:26:34,490 [22989 ] [INFO ][pool-2-thread-5] - Time taken to Process new payments for serverId 9 : 10 Sec 
2014-06-26 16:26:34,521 [23020 ] [INFO ][pool-2-thread-1] - Completed processing new payments for serverID: 5 
2014-06-26 16:26:34,521 [23020 ] [INFO ][pool-2-thread-1] - Time taken to Process new payments for serverId 5 : 10 Sec 
2014-06-26 16:26:34,521 [23020 ] [INFO ][main] - ShutDown complete 
2014-06-26 16:26:34,521 [23020 ] [INFO ][main] - ProcessDeamon iteration finished in 0 Sec 
2014-06-26 16:26:34,521 [23020 ] [INFO ][main] - ProcessDeamon iteration started 

Answer 1

不要關閉你的線程池，但重新使用它。這就是擁有一個線程池的關鍵：你將任務提交到這個池中，而不必關心線程管理。等待你的線程終止並將下一批任務提交到同一個池中。