前端使用sockjs，后台使用spring的websocket框架
结果在一个网络较慢的地方，发现tomcat报错信息：
Oct 28, 2015 10:10:43 AM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [mvc-dispatcher] in context with path [/rscc] threw exception [Request processing failed; nested exception is org.springframework.web.socket.sockjs.SockJsException: Uncaught failure in SockJS request, uri=http://xxx/user/854/qckzogtf/xhr_streaming; nested exception is org.springframework.web.socket.sockjs.SockJsException: Uncaught failure for request http://xxx/user/854/qckzogtf/xhr_streaming; nested exception is java.lang.IllegalArgumentException: Async support must be enabled on a servlet and for all filters involved in async request processing. This is done in Java code using the Servlet API or by adding "<async-supported>true</async-supported>" to servlet and filter declarations in web.xml. Also you must use a Servlet 3.0+ container] with root cause
java.lang.IllegalArgumentException: Async support must be enabled on a servlet and for all filters involved in async request processing. This is done in Java code using the Servlet API or by adding "<async-supported>true</async-supported>" to servlet and filter declarations in web.xml. Also you must use a Servlet 3.0+ container
at org.springframework.util.Assert.isTrue(Assert.java:65)
at org.springframework.http.server.ServletServerHttpAsyncRequestControl.<init>(ServletServerHttpAsyncRequestControl.java:59)
at org.springframework.http.server.ServletServerHttpRequest.getAsyncRequestControl(ServletServerHttpRequest.java:202)
at org.springframework.web.socket.sockjs.transport.session.AbstractHttpSockJsSession.initRequest(AbstractHttpSockJsSession.java:238)
at org.springframework.web.socket.sockjs.transport.session.AbstractHttpSockJsSession.handleInitialRequest(AbstractHttpSockJsSession.java:203)
at org.springframework.web.socket.sockjs.transport.session.StreamingSockJsSession.handleInitialRequest(StreamingSockJsSession.java:54)
at org.springframework.web.socket.sockjs.transport.handler.AbstractHttpSendingTransportHandler.handleRequestInternal(AbstractHttpSendingTransportHandler.java:66)
at org.springframework.web.socket.sockjs.transport.handler.AbstractHttpSendingTransportHandler.handleRequest(AbstractHttpSendingTransportHandler.java:58)
at org.springframework.web.socket.sockjs.transport.TransportHandlingSockJsService.handleTransportRequest(TransportHandlingSockJsService.java:254)
at org.springframework.web.socket.sockjs.support.AbstractSockJsService.handleRequest(AbstractSockJsService.java:317)
at org.springframework.web.socket.sockjs.support.SockJsHttpRequestHandler.handleRequest(SockJsHttpRequestHandler.java:88)
at org.springframework.web.servlet.mvc.HttpRequestHandlerAdapter.handle(HttpRequestHandlerAdapter.java:51)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:938)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:870)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:961)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:863)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:646)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:837)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:108)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
根据报错信息来看，应该是缺少了<async-supported>true</async-supported>这个配置，这个是3.0开始支持的，async的请求需要开启async-supported。
但是该项目在我们本地从来没有出现过这个问题，情况说明及解决分析过程如下：
一、前端连接情况：ws = new SockJS( ‘url‘, undefined, {});
不加参数，sockjs默认会选择最优方式来连接，情况如下：
关于协议选择：在第一种连接方式超时时，sockjs会选择次优方式进行连接：
var _all_protocols = [‘websocket‘,
‘xdr-streaming‘,
‘xhr-streaming‘,
‘iframe-eventsource‘,
‘iframe-htmlfile‘,
‘xdr-polling‘,
‘xhr-polling‘,
‘iframe-xhr-polling‘,
‘jsonp-polling‘];
所有协议（连接方式）
检测所有可用协议并按优先级排序
utils.probeProtocols = function() {
var probed = {};
for(var i=0; i<_all_protocols.length; i++) {
var protocol = _all_protocols[i];
// User can have a typo in protocol name.
probed[protocol] = SockJS[protocol] &&
SockJS[protocol].enabled();
}
return probed;
};
utils.detectProtocols = function(probed, protocols_whitelist, info) {
var pe = {},
protocols = [];
if (!protocols_whitelist) protocols_whitelist = _all_protocols;
for(var i=0; i<protocols_whitelist.length; i++) {
var protocol = protocols_whitelist[i];
pe[protocol] = probed[protocol];
}
var maybe_push = function(protos) {
var proto = protos.shift();
if (pe[proto]) {
protocols.push(proto);
} else {
if (protos.length > 0) {
maybe_push(protos);
}
}
}
// 1. Websocket
if (info.websocket !== false) {
maybe_push([‘websocket‘]);
}
// 2. Streaming
if (pe[‘xhr-streaming‘] && !info.null_origin) {
protocols.push(‘xhr-streaming‘);
} else {
if (pe[‘xdr-streaming‘] && !info.cookie_needed && !info.null_origin) {
protocols.push(‘xdr-streaming‘);
} else {
maybe_push([‘iframe-eventsource‘,
‘iframe-htmlfile‘]);
}
}
// 3. Polling
if (pe[‘xhr-polling‘] && !info.null_origin) {
protocols.push(‘xhr-polling‘);
} else {
if (pe[‘xdr-polling‘] && !info.cookie_needed && !info.null_origin) {
protocols.push(‘xdr-polling‘);
} else {
maybe_push([‘iframe-xhr-polling‘,
‘jsonp-polling‘]);
}
}
return protocols;
}
连接时若超时切换协议的代码
while(1) {
var protocol = that.protocol = that._protocols.shift();
if (!protocol) {
return false;
}
// Some protocols require access to `body`, what if were in
// the `head`?
if (SockJS[protocol] &&
SockJS[protocol].need_body === true &&
(!_document.body ||
(typeof _document.readyState !== ‘undefined‘
&& _document.readyState !== ‘complete‘))) {
that._protocols.unshift(protocol);
that.protocol = ‘waiting-for-load‘;
utils.attachEvent(‘load‘, function(){
that._try_next_protocol();
});
return true;
}
//下面的to = 就是计算连接超时时间的，调用delay，在连接超时时关闭这个协议的连接。
if (!SockJS[protocol] ||
!SockJS[protocol].enabled(that._options)) {
that._debug(‘Skipping transport:‘, protocol);
} else {
var roundTrips = SockJS[protocol].roundTrips || 1;
var to = ((that._options.rto || 0) * roundTrips) || 5000;
that._transport_tref = utils.delay(to, function() {
if (that.readyState === SockJS.CONNECTING) {
// I can‘t understand how it is possible to run
// this timer, when the state is CLOSED, but
// apparently in IE everythin is possible.
that._didClose(2007, "Transport timeouted");
}
});
var connid = utils.random_string(8);
var trans_url = that._base_url + ‘/‘ + that._server + ‘/‘ + connid;
that._debug(‘Opening transport:‘, protocol, ‘ url:‘+trans_url,
‘ RTO:‘+that._options.rto);
that._transport = new SockJS[protocol](that, trans_url,
that._base_url);
return true;
}
}
观察上面报错信息中的uri：uri=http://xxx/user/854/qckzogtf/xhr_streaming; 因为正常情况下连接为websocket连接，这个uri应该为ws=http://xxx/user/854/qckzogtf/websocket，由此可见，这里应该是切换为xhr_streaming协议了
前面也说过，他们网络环境较慢，所以才想，应该是连接超时导致的，有上面可知，to为超时时间，计算公式为
var to = ((that._options.rto || 0) * roundTrips) || 5000;
关键在于that._options.rto，这个是new的时候的设置项，所以可以设置rto超时长一点。
结果发现设置中只有
that._options = {devel: false, debug: false, protocols_whitelist: [],info: undefined, rtt: undefined};
这几项，并没有rto，于是继续看
var SockJS = function(url, dep_protocols_whitelist, options) {
if (this === _window) {
// makes `new` optional
return new SockJS(url, dep_protocols_whitelist, options);
}
var that = this, protocols_whitelist;
that._options = {devel: false, debug: false, protocols_whitelist: [],
info: undefined, rtt: undefined};
if (options) {
utils.objectExtend(that._options, options);
}
that._base_url = utils.amendUrl(url);
that._server = that._options.server || utils.random_number_string(1000);
if (that._options.protocols_whitelist &&
that._options.protocols_whitelist.length) {
protocols_whitelist = that._options.protocols_whitelist;
} else {
// Deprecated API
if (typeof dep_protocols_whitelist === ‘string‘ &&
dep_protocols_whitelist.length > 0) {
protocols_whitelist = [dep_protocols_whitelist];
} else if (utils.isArray(dep_protocols_whitelist)) {
protocols_whitelist = dep_protocols_whitelist
} else {
protocols_whitelist = null;
}
if (protocols_whitelist) {
that._debug(‘Deprecated API: Use "protocols_whitelist" option ‘ +
‘instead of supplying protocol list as a second ‘ +
‘parameter to SockJS constructor.‘);
}
}
that._protocols = [];
that.protocol = null;
that.readyState = SockJS.CONNECTING;
that._ir = createInfoReceiver(that._base_url);
that._ir.onfinish = function(info, rtt) {
that._ir = null;
if (info) {
if (that._options.info) {
// Override if user supplies the option
info = utils.objectExtend(info, that._options.info);
}
if (that._options.rtt) {
rtt = that._options.rtt;
}
that._applyInfo(info, rtt, protocols_whitelist);
that._didClose();
} else {
that._didClose(1002, ‘Can\‘t connect to server‘, true);
}
};
};
utils.objectExtend(that._options, options);这一句比较可疑是转移属性的，
that._applyInfo(info, rtt, protocols_whitelist);比较可疑，看一下
SockJS.prototype._applyInfo = function(info, rtt, protocols_whitelist) {
var that = this;
that._options.info = info;
that._options.rtt = rtt;
that._options.rto = utils.countRTO(rtt);
that._options.info.null_origin = !_document.domain;
var probed = utils.probeProtocols();
that._protocols = utils.detectProtocols(probed, protocols_whitelist, info);
};
rto设置找到了！that._options.rto = utils.countRTO(rtt);
utils.countRTO = function (rtt) {
var rto;
if (rtt > 100) {
rto = 3 * rtt; // rto > 300msec
} else {
rto = rtt + 200; // 200msec < rto <= 300msec
}
return rto;
}
好了，只用设置rtt既可以设置rto了。。。就这样，连接超时的问题算是解决了。
二、但是还没完，就算websocket连接超时导致协议切换为xhr_streaming，也不会导致后台报错的情况出现，下面解决这个问题：
报错处的代码：在AbstractHttpSockJsSession类中：
private void initRequest(ServerHttpRequest request, ServerHttpResponse response,
SockJsFrameFormat frameFormat) {
Assert.notNull(request, "Request must not be null");
Assert.notNull(response, "Response must not be null");
Assert.notNull(frameFormat, "SockJsFrameFormat must not be null");
this.response = response;
this.frameFormat = frameFormat;
this.asyncRequestControl = request.getAsyncRequestControl(response);
}
最后一句报错咯，看代码：
public ServerHttpAsyncRequestControl getAsyncRequestControl(ServerHttpResponse response) {
if (this.asyncRequestControl == null) {
Assert.isInstanceOf(ServletServerHttpResponse.class, response);
ServletServerHttpResponse servletServerResponse = (ServletServerHttpResponse) response;
this.asyncRequestControl = new ServletServerHttpAsyncRequestControl(this, servletServerResponse);//这一句报错了
}
return this.asyncRequestControl;
}
new ServletServerHttpAsyncRequestControl时报错
时间： 2024-08-06 14:48:26