@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
resp.getWriter().write(super.getServletName());
AsyncContext asyncContext = req.startAsync();
asyncContext.setTimeout(0);
/*
* O metodo createListener() cria um listener da classe informada que
* deve extender AsyncListener. Este metodo adiciona suporte para a
* notacoes e injecao de dependencias dentro do listener criado, deste
* modo, objetos sao injetados dentro desse listener depois que ele é
* criado.
*/
MyAsyncListener myAsyncListener = asyncContext.createListener(MyAsyncListener.class);
/*
* O metodo addListener(AsyncListener) registra o listener informado ao
* AsyncContext em questao.
*/
asyncContext.addListener(myAsyncListener);
/*
* O metodo addListener() é sobrecarregado para receber um
* ServletRequest e um ServletResponse, que podem ser recuperados mais
* tarde dentro do listener atraves dos metodos getSuppliedRequest() e
* getSuppliedResponse() de AsyncEvent.
*/
// asyncContext.addListener(myAsyncListener, null, null);
AsyncTask task = new AsyncTask(asyncContext);
asyncContext.start(task);
}
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
resp.getWriter().write("DispatchingServletGet-");
resp.flushBuffer();
final boolean first = TrackingServlet.first;
TrackingServlet.first = false;
final AsyncContext ctxt = req.startAsync();
TrackingListener listener = new TrackingListener(false, true, null);
ctxt.addListener(listener);
ctxt.setTimeout(3000);
Runnable run =
new Runnable() {
@Override
public void run() {
if (first) {
ctxt.dispatch("/stage1");
} else {
ctxt.dispatch("/stage2");
}
}
};
if ("y".equals(req.getParameter("useThread"))) {
new Thread(run).start();
} else {
run.run();
}
}
SampleAsycListener(HttpServletRequest request, HttpServletResponse response)
throws IOException {
asyncContext = request.startAsync();
asyncContext.setTimeout(10000L);
asyncContext.addListener(this);
servletOutputStream = response.getOutputStream();
servletOutputStream.setWriteListener(this);
this.response = response;
}
/* ------------------------------------------------------------ */
@Override
public void suspend() {
_resumed = false;
_expired = false;
_context = _request.startAsync();
_context.setTimeout(_timeoutMs);
for (AsyncListener listener : _listeners) _context.addListener(listener);
_listeners.clear();
}
@Override
protected void doGet(final HttpServletRequest req, final HttpServletResponse resp)
throws ServletException, IOException {
AsyncContext actxt = req.startAsync();
actxt.setTimeout(3000);
resp.setContentType("text/plain");
resp.getWriter().print("OK");
actxt.complete();
}
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
if (req.isAsyncSupported()) {
resp.getWriter().print("TimeoutServletGet-");
final AsyncContext ac = req.startAsync();
ac.setTimeout(3000);
ac.addListener(new TrackingListener(false, completeOnTimeout, dispatchUrl));
} else resp.getWriter().print("FAIL: Async unsupported");
}
/* ------------------------------------------------------------ */
@Override
public void suspend(ServletResponse response) {
_response = response;
_responseWrapped = response instanceof ServletResponseWrapper;
_resumed = false;
_expired = false;
_context = _request.startAsync();
_context.setTimeout(_timeoutMs);
for (AsyncListener listener : _listeners) _context.addListener(listener);
_listeners.clear();
}
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/event-stream");
response.setCharacterEncoding("UTF-8");
AsyncContext ac = request.startAsync();
ac.setTimeout(300000);
ac.addListener(
new AsyncListener() {
@Override
public void onTimeout(AsyncEvent ae) throws IOException {
activeClients.remove(ae.getAsyncContext());
publishToActiveClients(
ae.getAsyncContext().getRequest().getRemoteHost()
+ ":"
+ ae.getAsyncContext().getRequest().getRemotePort()
+ " has timedout...");
}
@Override
public void onError(AsyncEvent ae) throws IOException {
activeClients.remove(ae.getAsyncContext());
publishToActiveClients(
ae.getAsyncContext().getRequest().getRemoteHost()
+ ":"
+ ae.getAsyncContext().getRequest().getRemotePort()
+ " has errors...");
}
@Override
public void onComplete(AsyncEvent ae) throws IOException {
activeClients.remove(ae.getAsyncContext());
publishToActiveClients(
ae.getAsyncContext().getRequest().getRemoteHost()
+ ":"
+ ae.getAsyncContext().getRequest().getRemotePort()
+ " completed...");
}
@Override
public void onStartAsync(AsyncEvent ae) throws IOException {
publishToActiveClients(
ae.getAsyncContext().getRequest().getRemoteHost()
+ ":"
+ ae.getAsyncContext().getRequest().getRemotePort()
+ " started...");
}
});
activeClients.add(ac);
ac.getResponse().getWriter().flush();
publishToActiveClients(getRequestDescription(request) + " joined...");
}
/**
* Caso o response ja esteja fechado ou o metodo startAsync() ja tenha sido chamado, uma nova
* invocacao resultara em uma IllegalStateException.
*/
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
PrintWriter writer = resp.getWriter();
writer.println("Antes de iniciar a tarefa assincrona");
/*
* Para iniciar uma requisicao assincrona, basta chamar o metodo
* startAsync de ServletRequest. O metodo startAsync é sobrecarregado
* para receber um ServletRequest e um ServletResponse, desta forma é
* possivel passar wrappers para ele. Caso o metodo startAsync seja
* chamado, os objetos ServletRequest e Response originais serao
* utilizados.
*/
AsyncContext asyncContext = req.startAsync();
MyAsyncTask asyncTask = new MyAsyncTask(asyncContext, writer);
/*
* O tempo padrao de time out depende do container, geralmente está
* entre 5 e 10 segundos. Para desabilitar o time out basta informar um
* valor negativo ou 0. Esse metodo pode ser chamado antes ou depois do
* metodo start().
*/
asyncContext.setTimeout(-1);
/*
* A Interface AsyncContext possui metodos para configurar a tarefa
* assincrona e inicializar a mesma. O metodo estart recebe um runnable
* que sera responsavel por realizar o processamento da tarefa
* assincrona. Quando esse metodo é chamado, o processamento é realizado
* por outra Thread do pool de Threads do servidor.
*/
asyncContext.start(asyncTask);
/*
* Depois do start() da tarefa assincrona, o fluxo continua normalmente,
* e quando o metodo service() é encerrado, a resposta nao é commitada
* enquanto o metodo complete() de AsyncContext não for chamado. Desta
* forma, o container processa a tarefa assincrona um background em
* outra Thread.
*/
writer.println("Depois de iniciar a tarefa assincrona");
/*
* Retorna o AsyncContext inicializado para esse request. Caso o metodo
* startAsync() ainda nao tenha sido chamado, uma IllegalStateException
* ocorrera.
*/
req.getAsyncContext();
}
@Override
protected void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
AsyncContext asyncContext = (AsyncContext) request.getAttribute(AsyncContext.class.getName());
if (asyncContext == null) {
AsyncContext context = request.startAsync();
context.setTimeout(0);
request.setAttribute(AsyncContext.class.getName(), context);
context.addListener(this);
} else {
throw new ServletException();
}
}
synchronized void processPendingResponses(HttpServletRequest req, HttpServletResponse resp)
throws IOException {
JSONArray responses = new JSONArray();
JSONStreamAware pendingResponse;
while ((pendingResponse = pendingResponses.poll()) != null) {
responses.add(pendingResponse);
}
if (responses.size() > 0) {
JSONObject combinedResponse = new JSONObject();
combinedResponse.put("responses", responses);
if (asyncContext != null) {
asyncContext.getResponse().setContentType("text/plain; charset=UTF-8");
try (Writer writer = asyncContext.getResponse().getWriter()) {
combinedResponse.writeJSONString(writer);
}
asyncContext.complete();
asyncContext = req.startAsync();
asyncContext.addListener(new UserAsyncListener());
asyncContext.setTimeout(5000);
} else {
resp.setContentType("text/plain; charset=UTF-8");
try (Writer writer = resp.getWriter()) {
combinedResponse.writeJSONString(writer);
}
}
} else {
if (asyncContext != null) {
asyncContext.getResponse().setContentType("text/plain; charset=UTF-8");
try (Writer writer = asyncContext.getResponse().getWriter()) {
JSON.emptyJSON.writeJSONString(writer);
}
asyncContext.complete();
}
asyncContext = req.startAsync();
asyncContext.addListener(new UserAsyncListener());
asyncContext.setTimeout(5000);
}
}
@Override
protected void doGet(final HttpServletRequest req, final HttpServletResponse resp)
throws ServletException, IOException {
String echo = req.getParameter("echo");
AsyncContext actxt = req.startAsync();
resp.setContentType("text/plain");
resp.getWriter().print("OK");
if (echo != null) {
resp.getWriter().print("-" + echo);
}
// Speed up the test by reducing the timeout
actxt.setTimeout(1000);
}
private synchronized void poll(
HttpServletRequest request, HttpServletResponse response, String username)
throws IOException {
Map<String, Member> room = _rooms.get(request.getPathInfo());
if (room == null) {
response.sendError(503);
return;
}
final Member member = room.get(username);
if (member == null) {
response.sendError(503);
return;
}
synchronized (member) {
if (member._queue.size() > 0) {
// Send one chat message
response.setContentType("text/json;charset=utf-8");
StringBuilder buf = new StringBuilder();
buf.append("{\"action\":\"poll\",");
buf.append("\"from\":\"");
buf.append(member._queue.poll());
buf.append("\",");
String message = member._queue.poll();
int quote = message.indexOf('"');
while (quote >= 0) {
message = message.substring(0, quote) + '\\' + message.substring(quote);
quote = message.indexOf('"', quote + 2);
}
buf.append("\"chat\":\"");
buf.append(message);
buf.append("\"}");
byte[] bytes = buf.toString().getBytes("utf-8");
response.setContentLength(bytes.length);
response.getOutputStream().write(bytes);
} else {
AsyncContext async = request.startAsync();
async.setTimeout(10000);
async.addListener(member);
if (!member._async.compareAndSet(null, async)) throw new IllegalStateException();
}
}
}
/* (non-Javadoc)
* @see javax.servlet.http.HttpServlet#service(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
*/
@Override
protected void service(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
resp.setContentType("text/html;charset=UTF-8");
PrintWriter out = resp.getWriter();
String str1 = "进入Servlet的时间：" + new Date() + ".";
out.write(str1);
System.out.println(str1);
out.flush();
// 在子线程中执行业务调用，并由其负责输出响应，主线程退出
final AsyncContext ctx = req.startAsync();
ctx.setTimeout(200000);
new Work(ctx).start();
ctx.addListener(new AsynServletListener());
String str2 = "结束Servlet的时间：" + new Date() + ".";
out.println(str2);
out.flush();
System.out.println(str2);
}
@RequestMapping("/log")
@NeedLogin
public void log(HttpServletRequest request, HttpServletResponse response) {
/*String filename = request.getParameter("filename");
File file = new File(filename);
if(!file.exists()){
return "file.not.exist";
}*/
final AsyncContext asyncContext = request.startAsync();
asyncContext.setTimeout(-1);
Thread thread =
new Thread() {
boolean flag = true;
public void run() {
while (flag) {
try {
Thread.sleep(1000);
asyncContext
.getResponse()
.getWriter()
.println("currentTIme == " + System.currentTimeMillis());
} catch (Exception e) {
e.printStackTrace();
flag = false;
}
}
}
};
thread.start();
}
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
boolean accepted = false;
try {
Boolean suspended = (Boolean) request.getAttribute(_suspended);
if (suspended == null) {
accepted = _passes.tryAcquire(getWaitMs(), TimeUnit.MILLISECONDS);
if (accepted) {
request.setAttribute(_suspended, Boolean.FALSE);
if (LOG.isDebugEnabled()) LOG.debug("Accepted {}", request);
} else {
request.setAttribute(_suspended, Boolean.TRUE);
int priority = getPriority(request);
AsyncContext asyncContext = request.startAsync();
long suspendMs = getSuspendMs();
if (suspendMs > 0) asyncContext.setTimeout(suspendMs);
asyncContext.addListener(_listeners[priority]);
_queues[priority].add(asyncContext);
if (LOG.isDebugEnabled()) LOG.debug("Suspended {}", request);
return;
}
} else {
if (suspended) {
request.setAttribute(_suspended, Boolean.FALSE);
Boolean resumed = (Boolean) request.getAttribute(_resumed);
if (resumed == Boolean.TRUE) {
_passes.acquire();
accepted = true;
if (LOG.isDebugEnabled()) LOG.debug("Resumed {}", request);
} else {
// Timeout! try 1 more time.
accepted = _passes.tryAcquire(getWaitMs(), TimeUnit.MILLISECONDS);
if (LOG.isDebugEnabled()) LOG.debug("Timeout {}", request);
}
} else {
// Pass through resume of previously accepted request.
_passes.acquire();
accepted = true;
if (LOG.isDebugEnabled()) LOG.debug("Passthrough {}", request);
}
}
if (accepted) {
chain.doFilter(request, response);
} else {
if (LOG.isDebugEnabled()) LOG.debug("Rejected {}", request);
((HttpServletResponse) response).sendError(HttpServletResponse.SC_SERVICE_UNAVAILABLE);
}
} catch (InterruptedException e) {
((HttpServletResponse) response).sendError(HttpServletResponse.SC_SERVICE_UNAVAILABLE);
} finally {
if (accepted) {
for (int p = _queues.length - 1; p >= 0; --p) {
AsyncContext asyncContext = _queues[p].poll();
if (asyncContext != null) {
ServletRequest candidate = asyncContext.getRequest();
Boolean suspended = (Boolean) candidate.getAttribute(_suspended);
if (suspended == Boolean.TRUE) {
candidate.setAttribute(_resumed, Boolean.TRUE);
asyncContext.dispatch();
break;
}
}
}
_passes.release();
}
}
}
@Override
protected void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
final boolean isSmile = QueryResource.APPLICATION_SMILE.equals(request.getContentType());
final ObjectMapper objectMapper = isSmile ? smileMapper : jsonMapper;
String host = hostFinder.getDefaultHost();
Query inputQuery = null;
boolean hasContent = request.getContentLength() > 0 || request.getContentType() != null;
boolean isQuery = request.getMethod().equals(HttpMethod.POST.asString());
long startTime = System.currentTimeMillis();
// queries only exist for POST
if (isQuery) {
try {
inputQuery = objectMapper.readValue(request.getInputStream(), Query.class);
if (inputQuery != null) {
host = hostFinder.getHost(inputQuery);
if (inputQuery.getId() == null) {
inputQuery = inputQuery.withId(UUID.randomUUID().toString());
}
}
} catch (IOException e) {
log.warn(e, "Exception parsing query");
final String errorMessage = e.getMessage() == null ? "no error message" : e.getMessage();
requestLogger.log(
new RequestLogLine(
new DateTime(),
request.getRemoteAddr(),
null,
new QueryStats(
ImmutableMap.<String, Object>of("success", false, "exception", errorMessage))));
response.setStatus(HttpServletResponse.SC_BAD_REQUEST);
response.setContentType(QueryResource.APPLICATION_JSON);
objectMapper.writeValue(response.getOutputStream(), ImmutableMap.of("error", errorMessage));
return;
} catch (Exception e) {
handleException(response, objectMapper, e);
return;
}
}
URI rewrittenURI = rewriteURI(host, request);
if (rewrittenURI == null) {
onRewriteFailed(request, response);
return;
}
final Request proxyRequest =
getHttpClient()
.newRequest(rewrittenURI)
.method(request.getMethod())
.version(HttpVersion.fromString(request.getProtocol()));
// Copy headers
for (Enumeration<String> headerNames = request.getHeaderNames();
headerNames.hasMoreElements(); ) {
String headerName = headerNames.nextElement();
if (HttpHeader.TRANSFER_ENCODING.is(headerName)) {
hasContent = true;
}
for (Enumeration<String> headerValues = request.getHeaders(headerName);
headerValues.hasMoreElements(); ) {
String headerValue = headerValues.nextElement();
if (headerValue != null) {
proxyRequest.header(headerName, headerValue);
}
}
}
// Add proxy headers
addViaHeader(proxyRequest);
addXForwardedHeaders(proxyRequest, request);
final AsyncContext asyncContext = request.startAsync();
// We do not timeout the continuation, but the proxy request
asyncContext.setTimeout(0);
proxyRequest.timeout(getTimeout(), TimeUnit.MILLISECONDS);
if (hasContent) {
if (inputQuery != null) {
proxyRequest.content(new BytesContentProvider(jsonMapper.writeValueAsBytes(inputQuery)));
} else {
proxyRequest.content(proxyRequestContent(proxyRequest, request));
}
}
customizeProxyRequest(proxyRequest, request);
if (isQuery) {
proxyRequest.send(
newMetricsEmittingProxyResponseListener(request, response, inputQuery, startTime));
} else {
proxyRequest.send(newProxyResponseListener(request, response));
}
}
/* ------------------------------------------------------------ */
@Override
public void setTimeout(long timeoutMs) {
_timeoutMs = timeoutMs;
if (_context != null) _context.setTimeout(timeoutMs);
}
protected void doFilter(
HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
throws IOException, ServletException {
if (!isEnabled()) {
filterChain.doFilter(request, response);
return;
}
// Look for the rate tracker for this request.
RateTracker tracker = (RateTracker) request.getAttribute(__TRACKER);
if (tracker == null) {
// This is the first time we have seen this request.
if (LOG.isDebugEnabled()) LOG.debug("Filtering {}", request);
// Get a rate tracker associated with this request, and record one hit.
tracker = getRateTracker(request);
// Calculate the rate and check it is over the allowed limit
final boolean overRateLimit = tracker.isRateExceeded(System.currentTimeMillis());
// Pass it through if we are not currently over the rate limit.
if (!overRateLimit) {
if (LOG.isDebugEnabled()) LOG.debug("Allowing {}", request);
doFilterChain(filterChain, request, response);
return;
}
// We are over the limit.
// So either reject it, delay it or throttle it.
long delayMs = getDelayMs();
boolean insertHeaders = isInsertHeaders();
switch ((int) delayMs) {
case -1:
{
// Reject this request.
LOG.warn(
"DOS ALERT: Request rejected ip={}, session={}, user={}",
request.getRemoteAddr(),
request.getRequestedSessionId(),
request.getUserPrincipal());
if (insertHeaders) response.addHeader("DoSFilter", "unavailable");
response.sendError(getTooManyCode());
return;
}
case 0:
{
// Fall through to throttle the request.
LOG.warn(
"DOS ALERT: Request throttled ip={}, session={}, user={}",
request.getRemoteAddr(),
request.getRequestedSessionId(),
request.getUserPrincipal());
request.setAttribute(__TRACKER, tracker);
break;
}
default:
{
// Insert a delay before throttling the request,
// using the suspend+timeout mechanism of AsyncContext.
LOG.warn(
"DOS ALERT: Request delayed={}ms, ip={}, session={}, user={}",
delayMs,
request.getRemoteAddr(),
request.getRequestedSessionId(),
request.getUserPrincipal());
if (insertHeaders) response.addHeader("DoSFilter", "delayed");
request.setAttribute(__TRACKER, tracker);
AsyncContext asyncContext = request.startAsync();
if (delayMs > 0) asyncContext.setTimeout(delayMs);
asyncContext.addListener(new DoSTimeoutAsyncListener());
return;
}
}
}
if (LOG.isDebugEnabled()) LOG.debug("Throttling {}", request);
// Throttle the request.
boolean accepted = false;
try {
// Check if we can afford to accept another request at this time.
accepted = _passes.tryAcquire(getMaxWaitMs(), TimeUnit.MILLISECONDS);
if (!accepted) {
// We were not accepted, so either we suspend to wait,
// or if we were woken up we insist or we fail.
Boolean throttled = (Boolean) request.getAttribute(__THROTTLED);
long throttleMs = getThrottleMs();
if (throttled != Boolean.TRUE && throttleMs > 0) {
int priority = getPriority(request, tracker);
request.setAttribute(__THROTTLED, Boolean.TRUE);
if (isInsertHeaders()) response.addHeader("DoSFilter", "throttled");
AsyncContext asyncContext = request.startAsync();
request.setAttribute(_suspended, Boolean.TRUE);
if (throttleMs > 0) asyncContext.setTimeout(throttleMs);
asyncContext.addListener(_listeners[priority]);
_queues[priority].add(asyncContext);
if (LOG.isDebugEnabled()) LOG.debug("Throttled {}, {}ms", request, throttleMs);
return;
}
Boolean resumed = (Boolean) request.getAttribute(_resumed);
if (resumed == Boolean.TRUE) {
// We were resumed, we wait for the next pass.
_passes.acquire();
accepted = true;
}
}
// If we were accepted (either immediately or after throttle)...
if (accepted) {
// ...call the chain.
if (LOG.isDebugEnabled()) LOG.debug("Allowing {}", request);
doFilterChain(filterChain, request, response);
} else {
// ...otherwise fail the request.
if (LOG.isDebugEnabled()) LOG.debug("Rejecting {}", request);
if (isInsertHeaders()) response.addHeader("DoSFilter", "unavailable");
response.sendError(getTooManyCode());
}
} catch (InterruptedException e) {
LOG.ignore(e);
response.sendError(getTooManyCode());
} finally {
if (accepted) {
try {
// Wake up the next highest priority request.
for (int p = _queues.length - 1; p >= 0; --p) {
AsyncContext asyncContext = _queues[p].poll();
if (asyncContext != null) {
ServletRequest candidate = asyncContext.getRequest();
Boolean suspended = (Boolean) candidate.getAttribute(_suspended);
if (suspended == Boolean.TRUE) {
if (LOG.isDebugEnabled()) LOG.debug("Resuming {}", request);
candidate.setAttribute(_resumed, Boolean.TRUE);
asyncContext.dispatch();
break;
}
}
}
} finally {
_passes.release();
}
}
}
}
