我有一个Java应用程序，它运行一系列并行线程，从AmazonS3下载大量对象。我注意到，在没有任何问题的情况下运行了几个小时之后，最终得到一个特定的块会挂起并导致程序冻结。
Java进程仍在运行，但CPU使用率和网络IO都很小。执行线程转储时，有一个线程永远不会离开IN_NATIVE状态，而socketRead0（）似乎永远不会在SSL握手期间返回。这是释义的堆栈跟踪：
Thread 17260: (state = IN_NATIVE) - java.net.SocketInputStream.socketRead0(java.io.FileDescriptor, byte[], int, int, int) @bci=0 (Compiled frame; information may be imprecise) - java.net.SocketInputStream.socketRead(java.io.FileDescriptor, byte[], int, int, int) @bci=8, line=116 (Compiled frame) - java.net.SocketInputStream.read(byte[], int, int, int) @bci=79, line=170 (Compiled frame) - java.net.SocketInputStream.read(byte[], int, int) @bci=11, line=141 (Compiled frame) - sun.security.ssl.InputRecord.readFully(java.io.InputStream, byte[], int, int) @bci=21, line=465 (Compiled frame) - sun.security.ssl.InputRecord.read(java.io.InputStream, java.io.OutputStream) @bci=32, line=503 (Compiled frame) - sun.security.ssl.SSLSocketImpl.readRecord(sun.security.ssl.InputRecord, boolean) @bci=44, line=973 (Compiled frame) - sun.security.ssl.SSLSocketImpl.performInitialHandshake() @bci=84, line=1375 (Compiled frame) - sun.security.ssl.SSLSocketImpl.startHandshake(boolean) @bci=13, line=1403 (Compiled frame) - sun.security.ssl.SSLSocketImpl.startHandshake() @bci=2, line=1387 (Compiled frame) - org.apache.http.conn.ssl.SSLSocketFactory.connectSocket(int, java.net.Socket, org.apache.http.HttpHost, java.net.InetSocketAddress, java.net.InetSocketAddress, org.apache.http.protocol.HttpContext) @bci=87, line=533 (Compiled frame) - org.apache.http.conn.ssl.SSLSocketFactory.connectSocket(java.net.Socket, java.net.InetSocketAddress, java.net.InetSocketAddress, org.apache.http.params.HttpParams) @bci=69, line=401 (Compiled frame) - com.amazonaws.http.conn.ssl.SdkTLSSocketFactory.connectSocket(java.net.Socket, java.net.InetSocketAddress, java.net.InetSocketAddress, org.apache.http.params.HttpParams) @bci=60, line=128 (Compiled frame) - org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(org.apache.http.conn.OperatedClientConnection, org.apache.http.HttpHost, java.net.InetAddress, org.apache.http.protocol.HttpContext, org.apache.http.params.HttpParams) @bci=226, line=177 (Compiled frame) - org.apache.http.impl.conn.ManagedClientConnectionImpl.open(org.apache.http.conn.routing.HttpRoute, org.apache.http.protocol.HttpContext, org.apache.http.params.HttpParams) @bci=126, line=304 (Compiled frame) - org.apache.http.impl.client.DefaultRequestDirector.tryConnect(org.apache.http.impl.client.RoutedRequest, org.apache.http.protocol.HttpContext) @bci=50, line=610 (Compiled frame) - org.apache.http.impl.client.DefaultRequestDirector.execute(org.apache.http.HttpHost, org.apache.http.HttpRequest, org.apache.http.protocol.HttpContext) @bci=389, line=445 (Compiled frame) - org.apache.http.impl.client.AbstractHttpClient.doExecute(org.apache.http.HttpHost, org.apache.http.HttpRequest, org.apache.http.protocol.HttpContext) @bci=365, line=863 (Compiled frame) - org.apache.http.impl.client.CloseableHttpClient.execute(org.apache.http.client.methods.HttpUriRequest, org.apache.http.protocol.HttpContext) @bci=14, line=82 (Compiled frame) - org.apache.http.impl.client.CloseableHttpClient.execute(org.apache.http.client.methods.HttpUriRequest, org.apache.http.protocol.HttpContext) @bci=3, line=57 (Compiled frame) - com.amazonaws.http.AmazonHttpClient.executeOneRequest(com.amazonaws.Request, com.amazonaws.http.HttpResponseHandler, com.amazonaws.http.HttpResponseHandler, com.amazonaws.http.ExecutionContext, com.amazonaws.util.AWSRequestMetrics, com.amazonaws.http.AmazonHttpClient$ExecOneRequestParams) @bci=369, line=728 (Compiled frame) - com.amazonaws.http.AmazonHttpClient.executeHelper(com.amazonaws.Request, com.amazonaws.http.HttpResponseHandler, com.amazonaws.http.HttpResponseHandler, com.amazonaws.http.ExecutionContext) @bci=312, line=489 (Compiled frame) - com.amazonaws.http.AmazonHttpClient.execute(com.amazonaws.Request, com.amazonaws.http.HttpResponseHandler, com.amazonaws.http.HttpResponseHandler, com.amazonaws.http.ExecutionContext) @bci=150, line=310 (Compiled frame) - com.amazonaws.services.s3.AmazonS3Client.invoke(com.amazonaws.Request, com.amazonaws.http.HttpResponseHandler, java.lang.String, java.lang.String) @bci=168, line=3796 (Compiled frame) - com.amazonaws.services.s3.AmazonS3Client.getObject(com.amazonaws.services.s3.model.GetObjectRequest) @bci=235, line=1201 (Compiled frame) ...
以下是有关如何执行此操作的代码段：
protected static byte[] getChunk(AmazonS3Client client, long start, int offset, String bucket, String key) {
if(offset < 1){
return null;
}
S3Object obj = null;
S3ObjectInputStream is = null;
byte[] buffer = new byte[offset];
try {
GetObjectRequest request = new GetObjectRequest(bucket, key);
request.setRange(start, start + offset);
obj = client.getObject(request);
is = obj.getObjectContent();
int copied = 0;
int length;
while ((length = is.read(buffer,copied,offset-copied)) > 0){
copied += length;
}
buffer = (copied < 1) ? null : Arrays.copyOf(buffer, copied);
} catch (Exception e) {
buffer = null;
} finally {
Util.close(is);
}
return buffer;
}
作为旁注，如果可以使用不同的AmazonS3Client配置解决此问题，则以下是客户端的实例化方式：
private static final String S3_ENDPOINT = "https://s3.amazonaws.com/";
public static AmazonS3Client getAmazonClient(String accessKey, String secretKey){
AmazonS3Client client = null;
try {
ClientConfiguration clientConfig = new ClientConfiguration();
clientConfig.setProtocol(Protocol.HTTP);
AWSCredentials credentials = new BasicAWSCredentials(accessKey, secretKey);
client = new AmazonS3Client(credentials, clientConfig);
client.setEndpoint(S3_ENDPOINT);
} catch (Exception e){
e.printStackTrace();
client = null;
}
return client;
}
（这也是aws-java-sdk版本1.10.9）。以下是JVM规范：
java version "1.8.0_51" Java(TM) SE Runtime Environment (build 1.8.0_51-b16) Java HotSpot(TM) 64-Bit Server VM (build 25.51-b03, mixed mode)
如何解决这个问题的任何想法都会挂起套接字初始化？
答案 0 :(得分：0)
从你的代码中， 我可以看到这个
ClientConfiguration clientConfig = new ClientConfiguration();
ClientConfiguration附带了很多选项。
也许你可以用这个：
setSocketTimeout
并将其设置为5000。 根据文件：
设置在连接超时和关闭之前，通过已建立的打开连接传输数据的等待时间（以毫秒为单位）。值0表示无穷大，不建议使用。
DEFAULT_REQUEST_TIMEOUT的默认值为0。
REF：