调用方出现超时，空指针 问题

- [ ] I have searched the [issues](https://github.com/codingapi/tx-lcn/issues) of this repository and believe that this is not a duplicate.

### 1. Bug Description

### 2. Environment:
- JDK version: 1.8
- OS: Mac OS
- TX-LCN version: 5.0.2
- Others:

### 3. Exception Stacktrace

```
com.mysql.jdbc.exceptions.jdbc4.MySQLTransactionRollbackException: Lock wait timeout exceeded; try restarting transaction
java.lang.NullPointerException: null
at com.codingapi.txlcn.tc.core.checking.DefaultDTXExceptionHandler.handleNotifyGroupBusinessException(DefaultDTXExceptionHandler.java:93) ~[txlcn-tc-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at com.codingapi.txlcn.tc.core.template.TransactionControlTemplate.notifyGroup(TransactionControlTemplate.java:156) ~[txlcn-tc-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at com.codingapi.txlcn.tc.core.transaction.lcn.control.LcnStartingTransaction.postBusinessCode(LcnStartingTransaction.java:69) ~[txlcn-tc-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at com.codingapi.txlcn.tc.core.DTXServiceExecutor.transactionRunning(DTXServiceExecutor.java:108) ~[txlcn-tc-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at com.codingapi.txlcn.tc.aspect.weave.DTXLogicWeaver.runTransaction(DTXLogicWeaver.java:96) ~[txlcn-tc-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at com.codingapi.txlcn.tc.aspect.TransactionAspect.runWithLcnTransaction(TransactionAspect.java:93) ~[txlcn-tc-5.0.2.RELEASE.jar:5.0.2.RELEASE]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_201]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_201]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_201]
at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_201]
at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethodWithGivenArgs(AbstractAspectJAdvice.java:644) ~[spring-aop-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethod(AbstractAspectJAdvice.java:633) ~[spring-aop-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at org.springframework.aop.aspectj.AspectJAroundAdvice.invoke(AspectJAroundAdvice.java:70) ~[spring-aop-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:174) ~[spring-aop-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92) ~[spring-aop-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:688) ~[spring-aop-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at com.zm.business.service.impl.LoanCountServiceImpl$$EnhancerBySpringCGLIB$$c1552ab9.test() ~[classes/:?]
at com.zm.business.controller.TestController.test(TestController.java:23) ~[classes/:?]
at com.zm.business.controller.TestController$$FastClassBySpringCGLIB$$371907c0.invoke() ~[classes/:?]
at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204) ~[spring-core-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:746) ~[spring-aop-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) ~[spring-aop-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at org.springframework.aop.framework.adapter.MethodBeforeAdviceInterceptor.invoke(MethodBeforeAdviceInterceptor.java:56) ~[spring-aop-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at org.springframework.aop.framework.adapter.AfterReturningAdviceInterceptor.invoke(AfterReturningAdviceInterceptor.java:55) ~[spring-aop-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92) ~[spring-aop-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:688) ~[spring-aop-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at com.zm.business.controller.TestController$$EnhancerBySpringCGLIB$$21c98254.test() ~[classes/:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_201]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_201]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_201]
at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_201]
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:209) ~[spring-web-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136) ~[spring-web-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102) ~[spring-webmvc-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:891) ~[spring-webmvc-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:797) ~[spring-webmvc-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991) [spring-webmvc-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925) [spring-webmvc-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:981) [spring-webmvc-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:873) [spring-webmvc-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:687) [javax.servlet-api-3.1.0.jar:3.1.0]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:858) [spring-webmvc-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:790) [javax.servlet-api-3.1.0.jar:3.1.0]
at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:74) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:129) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at com.alibaba.druid.support.http.WebStatFilter.doFilter(WebStatFilter.java:124) [druid-1.1.14.jar:1.1.14]
at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at org.springframework.boot.actuate.web.trace.servlet.HttpTraceFilter.doFilterInternal(HttpTraceFilter.java:90) [spring-boot-actuator-2.0.8.RELEASE.jar:2.0.8.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) [spring-web-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:109) [spring-web-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93) [spring-web-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at org.springframework.session.web.http.SessionRepositoryFilter.doFilterInternal(SessionRepositoryFilter.java:151) [spring-session-core-2.0.9.RELEASE.jar:2.0.9.RELEASE]
at org.springframework.session.web.http.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:81) [spring-session-core-2.0.9.RELEASE.jar:2.0.9.RELEASE]
at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.filterAndRecordMetrics(WebMvcMetricsFilter.java:117) [spring-boot-actuator-2.0.8.RELEASE.jar:2.0.8.RELEASE]
at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:106) [spring-boot-actuator-2.0.8.RELEASE.jar:2.0.8.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200) [spring-web-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-5.0.12.RELEASE.jar:5.0.12.RELEASE]
at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.servlet.handlers.FilterHandler.handleRequest(FilterHandler.java:84) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.servlet.handlers.ServletChain$1.handleRequest(ServletChain.java:68) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:132) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) [undertow-core-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46) [undertow-core-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60) [undertow-core-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:77) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43) [undertow-core-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) [undertow-core-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) [undertow-core-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:292) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.servlet.handlers.ServletInitialHandler.access$100(ServletInitialHandler.java:81) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:138) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:135) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.servlet.core.ServletRequestContextThreadSetupAction$1.call(ServletRequestContextThreadSetupAction.java:48) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.servlet.core.ContextClassLoaderSetupAction$1.call(ContextClassLoaderSetupAction.java:43) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:272) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:81) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:104) [undertow-servlet-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.server.Connectors.executeRootHandler(Connectors.java:364) [undertow-core-2.0.19.Final.jar:2.0.19.Final]
at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:830) [undertow-core-2.0.19.Final.jar:2.0.19.Final]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:1.8.0_201]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:1.8.0_201]
at java.lang.Thread.run(Thread.java:748) [?:1.8.0_201]

```

### 4. Tour Idea
```
DefaultDTXExceptionHandler 异常处理器 ex为空导致 ex.getCause报错 最终无法执行结束事务
@Override
public void handleNotifyGroupBusinessException(Object params, Throwable ex) {
List paramList = (List) params;
String groupId = (String) paramList.get(0);
int state = (int) paramList.get(1);
String unitId = (String) paramList.get(2);
String transactionType = (String) paramList.get(3);

//用户强制回滚.
if (ex instanceof UserRollbackException) {
state = 0;
}
if ((ex.getCause() != null && ex.getCause() instanceof UserRollbackException)) {
state = 0;
}

// 结束事务
try {
transactionCleanTemplate.clean(groupId, unitId, transactionType, state);
} catch (TransactionClearException e) {
txLogger.error(groupId, unitId, "notify group", "{} > clean transaction error.", transactionType);
}
}
```