Fix occure the NPE when SpringMVC and hystrix work together

[ascrutae]

Please answer these questions before submitting pull request

• Why submit this pull request?

• Bug fix

• New feature provided

• Improve performance

• Related issues
  NPE when use hystrix in spring  #1238

[coveralls]

Coverage decreased (-0.004%) to 23.87% when pulling 3d967bd on ascrutae:fix/hystrix-springmvc into 29f6f6e on apache:master.

[wu-sheng]

@candyleer could you verify this pr? I think you have some cases.

[candyleer]

ok,I will test in last case

[candyleer]

@ascrutae I have tested in my case,but it also has NPE

this method will be invoked twice ,and sencond one will throw NPE,
1.works good

2.NPE

(NativeWebRequest)objInst.getSkyWalkingDynamicField() is null

and they are in the same thread

NPE

ERROR 2018-05-23 23:40:18 InstMethodsInter :  class[class org.springframework.web.method.HandlerMethod] after method[getBean] intercept failure
java.lang.NullPointerException
	at org.apache.skywalking.apm.plugin.spring.mvc.commons.interceptor.GetBeanInterceptor.afterMethod(GetBeanInterceptor.java:51)
	at org.apache.skywalking.apm.agent.core.plugin.interceptor.enhance.InstMethodsInter.intercept(InstMethodsInter.java:105)
	at org.springframework.web.method.HandlerMethod.getBean(HandlerMethod.java)
	at org.springframework.web.servlet.handler.AbstractHandlerMethodExceptionResolver.shouldApplyTo(AbstractHandlerMethodExceptionResolver.java:47)
	at org.springframework.web.servlet.handler.AbstractHandlerExceptionResolver.resolveException(AbstractHandlerExceptionResolver.java:131)
	at org.springframework.web.servlet.handler.HandlerExceptionResolverComposite.resolveException(HandlerExceptionResolverComposite.java:76)
	at org.springframework.web.servlet.DispatcherServlet.processHandlerException(DispatcherServlet.java:1222)
	at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1034)
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:984)
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901)
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:635)
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at com.example.test.CustomFilter.doFilter(CustomFilter.java:37)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)

[candyleer]

maybe you can modify like this?

 @Override
    public Object afterMethod(EnhancedInstance objInst, Method method, Object[] allArguments, Class<?>[] argumentsTypes,
        Object ret) throws Throwable {
        if (ret instanceof EnhancedInstance && objInst instanceof InvocableHandlerMethod) {
            ContextManager.getRuntimeContext().put(REQUEST_KEY_IN_RUNTIME_CONTEXT, ((ServletRequestAttributes)RequestContextHolder.getRequestAttributes()).getRequest());
            ContextManager.getRuntimeContext().put(RESPONSE_KEY_IN_RUNTIME_CONTEXT, ((NativeWebRequest)objInst.getSkyWalkingDynamicField()).getNativeResponse());
        }
        return ret;
    }

[ascrutae]

I had fix this. maybe you can try

[ascrutae]

Here is the test report

[wu-sheng]

Here is the test report

Thanks. Continue to wait for @candyleer feedback. :)

[candyleer]

test passed.

Thanks.