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[英]restlet: Using Server and Client restlet Jars in same web application
[英]Repeated calls by Restlet client to Restlet server hangs
我正在使用Restlet來實現Web服務。 客戶端(也使用Restlet)對服務器進行多次連續調用,但在少量調用成功完成后,進一步調用會掛起服務器,顯示消息:
信息:停止接受新的連接和事務。 考慮增加最大線程數。
我試過了:
getContext().getParameters().add("maxThreads", "200");
但這沒有用。 在任何情況下,似乎客戶端應該能夠進行無限數量的呼叫,並且增加maxThreads只會增加限制。 看起來我沒有釋放一些資源或在每次客戶電話后斷開連接,但我不知道該怎么做。
以下(我可以做的很小)獨立程序演示了這個問題。 它啟動一個簡單的服務器,然后客戶端多次調用它:
/** You may copy, modify, and re-use this code as you see fit - Jim Irrer */
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import org.restlet.Application;
import org.restlet.Component;
import org.restlet.Request;
import org.restlet.Response;
import org.restlet.Restlet;
import org.restlet.Server;
import org.restlet.data.MediaType;
import org.restlet.data.Method;
import org.restlet.data.Protocol;
import org.restlet.data.Status;
import org.restlet.representation.InputRepresentation;
import org.restlet.representation.Representation;
import org.restlet.resource.ClientResource;
import org.restlet.resource.Directory;
public class SimpleServerPut extends Component implements Runnable {
private static final int PORT = 8080;
private static int readToByteArray(InputStream inputStream, byte[] buf) throws IOException {
int length = 0;
int b;
while ((b = inputStream.read()) != -1) {
buf[length++] = (byte)b;
}
return length;
}
@Override
public void run() {
getContext().getParameters().add("maxThreads", "200");
// Create the HTTP server and listen on port PORT
SimpleServerPut simpleServer = new SimpleServerPut();
Server server = new Server(Protocol.HTTP, PORT, simpleServer);
simpleServer.getClients().add(Protocol.FILE);
// Create an application
Application application = new Application(simpleServer.getContext()) {
@Override
public Restlet createRoot() {
return new Directory(getContext(), "C:");
}
};
// Attach the application to the component and start it
simpleServer.getDefaultHost().attach("/stuff/", application);
try {
server.start();
}
catch (Exception ex) {
ex.printStackTrace();
}
}
@Override
public void handle(Request request, Response response) {
// assume the worst
response.setStatus(Status.CLIENT_ERROR_METHOD_NOT_ALLOWED);
response.setEntity("No no - Bad client! Only do PUTs.", MediaType.TEXT_PLAIN);
try {
if (request.getMethod() == Method.PUT) {
InputStream inputStream = request.getEntity().getStream();
byte[] buf = new byte[64*1024];
int totalLength = readToByteArray(inputStream, buf);
response.setStatus(Status.SUCCESS_OK);
String msg = "Number of bytes received: " + totalLength;
response.setEntity(msg, MediaType.TEXT_PLAIN);
System.out.println("server: " + msg);
return;
}
}
catch (Exception ex) {
ex.printStackTrace();
}
}
private static String callServer() throws IOException {
String urlText = "http://localhost:" + PORT + "/";
ClientResource clientResource = new ClientResource(urlText);
clientResource.setReferrerRef(urlText);
byte[] buf = new byte[1000];
for (int i = 0; i < buf.length; i++) {
buf[i] = (byte)((int)'a' + (i%26));
}
ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(buf);
Representation representation = new InputRepresentation(byteArrayInputStream, MediaType.APPLICATION_OCTET_STREAM);
Representation representation2 = clientResource.put(representation);
byte[] responseBuf = new byte[16*1024];
int length = readToByteArray(representation2.getStream(), responseBuf);
Response response = clientResource.getResponse();
Status status = response.getStatus();
return "status: " + status + " message: " + new String(responseBuf, 0, length);
}
// Start server and call it a bunch of times
public static void main(String[] args) throws Exception {
SimpleServerPut simpleServer = new SimpleServerPut();
new Thread(simpleServer).start();
Thread.sleep(200); // cheap trick to make sure that server is running
// make a bunch of client calls
for (int t = 0; t < 100; t++) {
System.out.println("client count: " + (t+1) + " " + callServer());
}
System.exit(0);
}
}
我們只能通過直接停止ClientResource的關聯客戶端來解決問題(使用Restlet版本2.0.15):
Client c = (Client)clientResource.getNext();
try {
c.stop();
} catch (Exception e) {
//handle exception
}
添加一行,以便客戶端釋放資源:
Response response = clientResource.getResponse();
Status status = response.getStatus();
clientResource.release(); // add this line
對客戶而言一切正常。 如果客戶端死亡,服務器最終會超時,但這需要一段時間。
我已經解決了下載Restlet API最后一個穩定版本的問題
顯然,我一直使用的.jar是舊版本,其中release()
命令沒有任何效果。
在更新之前,客戶端日志僅輸出客戶端的開頭:
Sep 05, 2012 9:50:19 AM org.restlet.engine.http.connector.HttpClientHelper start
INFO: Starting the default HTTP client
現在它也輸出了止損:
Sep 05, 2012 9:50:19 AM org.restlet.engine.http.connector.HttpClientHelper stop
INFO: Stopping the default HTTP client
除了調用ClientResource.release()之外,您可能還想在表示上調用exhaust()。
Representation responseRepresentation = response.getEntity();
if (responseRepresentation != null) {
try {
responseRepresentation.exhaust();
} catch (IOException e) {
// handle exception
}
responseRepresentation.release();
}
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