在webSocket中获取shiro报错

问题

 前面为了做一个shiro 过期检测。然后用来获取鼠标焦点，调用websocket去后台检测是否过期。（之所以这么做，还是前端技术不行）。
但是在handleMessage方法中，通过Subject subject = SecurityUtils.getSubject();的方式来直接获取subject时，会因为当前访问的连接并不在shiro的管理范围内，而报错
org.apache.shiro.UnavailableSecurityManagerException: No SecurityManager accessible to the calling code, either bound to the org.apache.shiro.util.ThreadContext or as a vm static singleton.  This is an invalid application configuration.
at org.apache.shiro.SecurityUtils.getSecurityManager(SecurityUtils.java:123)
at org.apache.shiro.subject.Subject$Builder.<init>(Subject.java:626)
at org.apache.shiro.SecurityUtils.getSubject(SecurityUtils.java:56)
at cn.xxxx.handleMessage(WebSocketHander.java:50)
at org.springframework.web.socket.handler.LoggingWebSocketHandlerDecorator.handleMessage(LoggingWebSocketHandlerDecorator.java:56)
at org.springframework.web.socket.handler.ExceptionWebSocketHandlerDecorator.handleMessage(ExceptionWebSocketHandlerDecorator.java:58)
at org.springframework.web.socket.adapter.standard.StandardWebSocketHandlerAdapter.handleTextMessage(StandardWebSocketHandlerAdapter.java:114)
at org.springframework.web.socket.adapter.standard.StandardWebSocketHandlerAdapter.access$000(StandardWebSocketHandlerAdapter.java:43)
at org.springframework.web.socket.adapter.standard.StandardWebSocketHandlerAdapter$3.onMessage(StandardWebSocketHandlerAdapter.java:85)
at org.springframework.web.socket.adapter.standard.StandardWebSocketHandlerAdapter$3.onMessage(StandardWebSocketHandlerAdapter.java:82)
at org.apache.tomcat.websocket.WsFrameBase.sendMessageText(WsFrameBase.java:394)
at org.apache.tomcat.websocket.server.WsFrameServer.sendMessageText(WsFrameServer.java:119)
at org.apache.tomcat.websocket.WsFrameBase.processDataText(WsFrameBase.java:495)
at org.apache.tomcat.websocket.WsFrameBase.processData(WsFrameBase.java:294)
at org.apache.tomcat.websocket.WsFrameBase.processInputBuffer(WsFrameBase.java:133)
at org.apache.tomcat.websocket.server.WsFrameServer.onDataAvailable(WsFrameServer.java:82)
at org.apache.tomcat.websocket.server.WsFrameServer.doOnDataAvailable(WsFrameServer.java:171)
at org.apache.tomcat.websocket.server.WsFrameServer.notifyDataAvailable(WsFrameServer.java:151)
at org.apache.tomcat.websocket.server.WsHttpUpgradeHandler.upgradeDispatch(WsHttpUpgradeHandler.java:148)
at org.apache.coyote.http11.upgrade.UpgradeProcessorInternal.dispatch(UpgradeProcessorInternal.java:54)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:59)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:810)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1506)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:748)

就是这个错误了。

解决办法

解决办法的话，主要是通过websocket的拦截器，在握手以前将需要的对象，注入到map中。然后就可以在handleMessage中，从session里取出来了。

拦截器实现：
@Override
public boolean beforeHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler, Map<String, Object> attributes) throws Exception {
Subject subject = SecurityUtils.getSubject();
Session shiroSession = subject.getSession();
attributes.put("shiroSession", shiroSession);
return super.beforeHandshake(request, response, wsHandler, attributes);
}
从websocketsession中取出。
Map<String, Object> attributes = webSocketSession.getAttributes();
Session shiroSession = (Session) attributes.get("shiroSession");
end;