AWS開發工具包-AmazonS3Client不會關閉

Question

我發現創建一個AmazonS3Client意味着我的流程即使在什么都不做的情況下也會死機。 我正在上傳文件，但已將其縮減為僅此一個。

當我運行以下代碼（使用有效的憑據）時，它會顯示“簡單完成”，但是直到最終maven：exec告訴我，該過程才會退出：

Simple is finished
[WARNING] thread Thread[java-sdk-http-connection-reaper,5,Simple] was interrupted but is still alive after waiting at least 15000msecs
[WARNING] thread Thread[java-sdk-http-connection-reaper,5,Simple] will linger despite being asked to die via interruption
[WARNING] NOTE: 1 thread(s) did not finish despite being asked to  via interruption. This is not a problem with exec:java, it is a problem with the running code. Although not serious, it should be remedied.
[WARNING] Couldn't destroy threadgroup org.codehaus.mojo.exec.ExecJavaMojo$IsolatedThreadGroup[name=Simple,maxpri=10]
java.lang.IllegalThreadStateException

編碼：

    import com.amazonaws.auth.AWSCredentials;
    import com.amazonaws.auth.BasicAWSCredentials;
    import com.amazonaws.services.s3.AmazonS3;
    import com.amazonaws.services.s3.AmazonS3Client;

    public class Simple {

        private static String accessKey = "XXX";
        private static String secretKey = "ZZZ";

        public static void main(String[] args) {

            AWSCredentials credentials = new BasicAWSCredentials(accessKey, secretKey);
            AmazonS3 s3client = new AmazonS3Client(credentials);
            System.out.println("Simple is finished");        
        }

    }

它應該像這樣工作嗎？ 有辦法殺死它嗎？

編輯：添加版本信息：

<dependency>
    <groupId>com.amazonaws</groupId>
    <artifactId>aws-java-sdk</artifactId>
    <version>1.9.33</version>
</dependency>

Answer 1

這些似乎工作：

((AmazonS3Client) s3client).shutdown();

要么

try {
    com.amazonaws.http.IdleConnectionReaper.shutdown();
} catch (Throwable t) {
    // etc
}

盡管我不確定它們的正確性。

Answer 2

上面的解決方案有效，這是另外兩個：

• 手動調用System.gc（）（在AmazonS3超出范圍后）
• 或者，在運行Maven時添加標志exec.cleanupDaemonThreads = false

我遇到了同樣的問題。 如果GC運行，AmazonS3Client實際上將通過垃圾回收進行清理； 但是，根據您的jvm，這可能永遠不會發生。 就我而言，即使使用-Dexec.daemonThreadJoinTimeout = -1運行，這也會使maven無限期地等待線程關閉，但它永遠不會關閉。

aws-java-sdk-s3版本1.10.24

Answer 3

由於我無法發表評論，因此我想為推薦此解決方案的答案提供更多背景信息：

((AmazonS3Client) s3client).shutdown();

根據《 aws開發人員指南》 ，直到客戶端被垃圾回收之前，連接池資源才真正被清除。 調用shutdown會強制客戶端釋放其資源，這就是該解決方案起作用的原因。

這是AmazonWebServiceClient.java（AmazonS3Client的父類）的關閉方法：

/**
 * Shuts down this client object, releasing any resources that might be held
 * open. This is an optional method, and callers are not expected to call
 * it, but can if they want to explicitly release any open resources. Once a
 * client has been shutdown, it should not be used to make any more
 * requests.
 */
public void shutdown() {
    client.shutdown();
}