/**
	 * Intercept the execution of a handler. Called after HandlerMapping determined
	 * an appropriate handler object, but before HandlerAdapter invokes the handler.
	 */
	default boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
			throws Exception {

		return true;
	}

	/**
	 * Intercept the execution of a handler. Called after HandlerAdapter actually
	 * invoked the handler, but before the DispatcherServlet renders the view.
	 * Can expose additional model objects to the view via the given ModelAndView.
	 */
	default void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
			@Nullable ModelAndView modelAndView) throws Exception {
	}

	/**
	 * Callback after completion of request processing, that is, after rendering
	 * the view. Will be called on any outcome of handler execution, thus allows
	 * for proper resource cleanup.
	 */
	default void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler,
			@Nullable Exception ex) throws Exception {
	}

/**
 * @author xiaojing
 *
 * Fescar HandlerInterceptor, Convert Fescar information into
 * @see com.alibaba.fescar.core.context.RootContext from http request's header in
 * {@link org.springframework.web.servlet.HandlerInterceptor#preHandle(HttpServletRequest , HttpServletResponse , Object )},
 * And clean up Fescar information after servlet method invocation in
 * {@link org.springframework.web.servlet.HandlerInterceptor#afterCompletion(HttpServletRequest, HttpServletResponse, Object, Exception)}
 */
public class FescarHandlerInterceptor implements HandlerInterceptor {

	private static final Logger log = LoggerFactory
			.getLogger(FescarHandlerInterceptor.class);

	@Override
	public boolean preHandle(HttpServletRequest request, HttpServletResponse response,
			Object handler) throws Exception {

		String xid = RootContext.getXID();
		String rpcXid = request.getHeader(RootContext.KEY_XID);
		if (log.isDebugEnabled()) {
			log.debug("xid in RootContext {} xid in RpcContext {}", xid, rpcXid);
		}

		if (xid == null && rpcXid != null) {
			RootContext.bind(rpcXid);
			if (log.isDebugEnabled()) {
				log.debug("bind {} to RootContext", rpcXid);
			}
		}
		return true;
	}

	@Override
	public void afterCompletion(HttpServletRequest request, HttpServletResponse response,
			Object handler, Exception e) throws Exception {

		String rpcXid = request.getHeader(RootContext.KEY_XID);

		if (StringUtils.isEmpty(rpcXid)) {
			return;
		}

		String unbindXid = RootContext.unbind();
		if (log.isDebugEnabled()) {
			log.debug("unbind {} from RootContext", unbindXid);
		}
		if (!rpcXid.equalsIgnoreCase(unbindXid)) {
			log.warn("xid in change during RPC from {} to {}", rpcXid, unbindXid);
			if (unbindXid != null) {
				RootContext.bind(unbindXid);
				log.warn("bind {} back to RootContext", unbindXid);
			}
		}
	}

}

public class FescarRestTemplateInterceptor implements ClientHttpRequestInterceptor {
	@Override
	public ClientHttpResponse intercept(HttpRequest httpRequest, byte[] bytes,
			ClientHttpRequestExecution clientHttpRequestExecution) throws IOException {
		HttpRequestWrapper requestWrapper = new HttpRequestWrapper(httpRequest);

		String xid = RootContext.getXID();

		if (!StringUtils.isEmpty(xid)) {
			requestWrapper.getHeaders().add(RootContext.KEY_XID, xid);
		}
		return clientHttpRequestExecution.execute(requestWrapper, bytes);
	}
}

@Configuration
public class FescarRestTemplateAutoConfiguration {

	@Bean
	public FescarRestTemplateInterceptor fescarRestTemplateInterceptor() {
		return new FescarRestTemplateInterceptor();
	}

	@Autowired(required = false)
	private Collection<RestTemplate> restTemplates;

	@Autowired
	private FescarRestTemplateInterceptor fescarRestTemplateInterceptor;

	@PostConstruct
	public void init() {
		if (this.restTemplates != null) {
			for (RestTemplate restTemplate : restTemplates) {
				List<ClientHttpRequestInterceptor> interceptors = new ArrayList<ClientHttpRequestInterceptor>(
						restTemplate.getInterceptors());
				interceptors.add(this.fescarRestTemplateInterceptor);
				restTemplate.setInterceptors(interceptors);
			}
		}
	}

}

@Configuration
@ConditionalOnClass(Client.class)
@AutoConfigureBefore(FeignAutoConfiguration.class)
public class FescarFeignClientAutoConfiguration {

	@Bean
	@Scope("prototype")
	@ConditionalOnClass(name = "com.netflix.hystrix.HystrixCommand")
	@ConditionalOnProperty(name = "feign.hystrix.enabled", havingValue = "true")
	Feign.Builder feignHystrixBuilder(BeanFactory beanFactory) {
		return FescarHystrixFeignBuilder.builder(beanFactory);
	}

	@Bean
	@Scope("prototype")
	@ConditionalOnClass(name = "com.alibaba.csp.sentinel.SphU")
	@ConditionalOnProperty(name = "feign.sentinel.enabled", havingValue = "true")
	Feign.Builder feignSentinelBuilder(BeanFactory beanFactory) {
		return FescarSentinelFeignBuilder.builder(beanFactory);
	}

	@Bean
	@ConditionalOnMissingBean
	@Scope("prototype")
	Feign.Builder feignBuilder(BeanFactory beanFactory) {
		return FescarFeignBuilder.builder(beanFactory);
	}

	@Configuration
	protected static class FeignBeanPostProcessorConfiguration {

		@Bean
		FescarBeanPostProcessor fescarBeanPostProcessor(
				FescarFeignObjectWrapper fescarFeignObjectWrapper) {
			return new FescarBeanPostProcessor(fescarFeignObjectWrapper);
		}

		@Bean
		FescarContextBeanPostProcessor fescarContextBeanPostProcessor(
				BeanFactory beanFactory) {
			return new FescarContextBeanPostProcessor(beanFactory);
		}

		@Bean
		FescarFeignObjectWrapper fescarFeignObjectWrapper(BeanFactory beanFactory) {
			return new FescarFeignObjectWrapper(beanFactory);
		}
	}

}

HystrixFeign.builder().retryer(Retryer.NEVER_RETRY)
      .client(new FescarFeignClient(beanFactory))

SentinelFeign.builder().retryer(Retryer.NEVER_RETRY)
				.client(new FescarFeignClient(beanFactory));

Feign.builder().client(new FescarFeignClient(beanFactory));

public class FescarFeignClient implements Client {

	private final Client delegate;
	private final BeanFactory beanFactory;

	FescarFeignClient(BeanFactory beanFactory) {
		this.beanFactory = beanFactory;
		this.delegate = new Client.Default(null, null);
	}

	FescarFeignClient(BeanFactory beanFactory, Client delegate) {
		this.delegate = delegate;
		this.beanFactory = beanFactory;
	}

	@Override
	public Response execute(Request request, Request.Options options) throws IOException {

		Request modifiedRequest = getModifyRequest(request);

		try {
			return this.delegate.execute(modifiedRequest, options);
		}
		finally {

		}
	}

	private Request getModifyRequest(Request request) {

		String xid = RootContext.getXID();

		if (StringUtils.isEmpty(xid)) {
			return request;
		}

		Map<String, Collection<String>> headers = new HashMap<>();
		headers.putAll(request.headers());

		List<String> fescarXid = new ArrayList<>();
		fescarXid.add(xid);
		headers.put(RootContext.KEY_XID, fescarXid);

		return Request.create(request.method(), request.url(), headers, request.body(),
				request.charset());
	}

    @Override
	public Object postProcessBeforeInitialization(Object bean, String beanName)
			throws BeansException {
		if (bean instanceof FeignContext && !(bean instanceof FescarFeignContext)) {
			return new FescarFeignContext(getFescarFeignObjectWrapper(),
					(FeignContext) bean);
		}
		return bean;
	}

	@Override
	public Object postProcessAfterInitialization(Object bean, String beanName)
			throws BeansException {
		return bean;
	}

    @Bean
	public FeignContext feignContext() {
		FeignContext context = new FeignContext();
		context.setConfigurations(this.configurations);
		return context;
	}

	/**
	 * @param <T> the target type of the Feign client
	 * @return a {@link Feign} client created with the specified data and the context information
	 */
	<T> T getTarget() {
		FeignContext context = applicationContext.getBean(FeignContext.class);
		Feign.Builder builder = feign(context);

		if (!StringUtils.hasText(this.url)) {
			if (!this.name.startsWith("http")) {
				url = "http://" + this.name;
			}
			else {
				url = this.name;
			}
			url += cleanPath();
			return (T) loadBalance(builder, context, new HardCodedTarget<>(this.type,
					this.name, url));
		}
		if (StringUtils.hasText(this.url) && !this.url.startsWith("http")) {
			this.url = "http://" + this.url;
		}
		String url = this.url + cleanPath();
		Client client = getOptional(context, Client.class);
		if (client != null) {
			if (client instanceof LoadBalancerFeignClient) {
				// not load balancing because we have a url,
				// but ribbon is on the classpath, so unwrap
				client = ((LoadBalancerFeignClient)client).getDelegate();
			}
			builder.client(client);
		}
		Targeter targeter = get(context, Targeter.class);
		return (T) targeter.target(this, builder, context, new HardCodedTarget<>(
				this.type, this.name, url));
	}

	Object wrap(Object bean) {
		if (bean instanceof Client && !(bean instanceof FescarFeignClient)) {
			if (bean instanceof LoadBalancerFeignClient) {
				LoadBalancerFeignClient client = ((LoadBalancerFeignClient) bean);
				return new FescarLoadBalancerFeignClient(client.getDelegate(), factory(),
						clientFactory(), this.beanFactory);
			}
			return new FescarFeignClient(this.beanFactory, (Client) bean);
		}
		return bean;
	}

public class FescarHystrixConcurrencyStrategy extends HystrixConcurrencyStrategy {

	private HystrixConcurrencyStrategy delegate;

	public FescarHystrixConcurrencyStrategy() {
		this.delegate = HystrixPlugins.getInstance().getConcurrencyStrategy();
		HystrixPlugins.reset();
		HystrixPlugins.getInstance().registerConcurrencyStrategy(this);
	}

	@Override
	public <K> Callable<K> wrapCallable(Callable<K> c) {
		if (c instanceof FescarContextCallable) {
			return c;
		}

		Callable<K> wrappedCallable;
		if (this.delegate != null) {
			wrappedCallable = this.delegate.wrapCallable(c);
		}
		else {
			wrappedCallable = c;
		}
		if (wrappedCallable instanceof FescarContextCallable) {
			return wrappedCallable;
		}

		return new FescarContextCallable<>(wrappedCallable);
	}

	private static class FescarContextCallable<K> implements Callable<K> {

		private final Callable<K> actual;
		private final String xid;

		FescarContextCallable(Callable<K> actual) {
			this.actual = actual;
			this.xid = RootContext.getXID();
		}

		@Override
		public K call() throws Exception {
			try {
				RootContext.bind(xid);
				return actual.call();
			}
			finally {
				RootContext.unbind();
			}
		}

	}
}

@Configuration
@ConditionalOnClass(HystrixCommand.class)
public class FescarHystrixAutoConfiguration {

	@Bean
	FescarHystrixConcurrencyStrategy fescarHystrixConcurrencyStrategy() {
		return new FescarHystrixConcurrencyStrategy();
	}

}

registry {
  # file 、nacos 、eureka、redis、zk
  type = "nacos"

  nacos {
    serverAddr = "localhost"
    namespace = "public"
    cluster = "default"
  }
  eureka {
    serviceUrl = "http://localhost:1001/eureka"
    application = "default"
    weight = "1"
  }
  redis {
    serverAddr = "localhost:6379"
    db = "0"
  }
  zk {
    cluster = "default"
    serverAddr = "127.0.0.1:2181"
    session.timeout = 6000
    connect.timeout = 2000
  }
  file {
    name = "file.conf"
  }
}

config {
  # file、nacos 、apollo、zk
  type = "nacos"

  nacos {
    serverAddr = "localhost"
    namespace = "public"
    cluster = "default"
  }
  apollo {
    app.id = "fescar-server"
    apollo.meta = "http://192.168.1.204:8801"
  }
  zk {
    serverAddr = "127.0.0.1:2181"
    session.timeout = 6000
    connect.timeout = 2000
  }
  file {
    name = "file.conf"
  }
}

transport {
  # tcp udt unix-domain-socket
  type = "TCP"
  #NIO NATIVE
  server = "NIO"
  #enable heartbeat
  heartbeat = true
  #thread factory for netty
  thread-factory {
    boss-thread-prefix = "NettyBoss"
    worker-thread-prefix = "NettyServerNIOWorker"
    server-executor-thread-prefix = "NettyServerBizHandler"
    share-boss-worker = false
    client-selector-thread-prefix = "NettyClientSelector"
    client-selector-thread-size = 1
    client-worker-thread-prefix = "NettyClientWorkerThread"
    # netty boss thread size,will not be used for UDT
    boss-thread-size = 1
    #auto default pin or 8
    worker-thread-size = 8
  }
}
service {
  #vgroup->rgroup
  vgroup_mapping.service-provider-fescar-service-group = "default"
  #only support single node
  localRgroup.grouplist = "127.0.0.1:8091"
  #degrade current not support
  enableDegrade = false
  #disable
  disable = false
}

client {
  async.commit.buffer.limit = 10000
  lock {
    retry.internal = 10
    retry.times = 30
  }
}

    grouplist IP，这里是当前fescar-sever的IP端口，
    vgroup_mapping的配置。

     vgroup_mapping.service-provider-fescar-service-group = "default"
      #only support single node
      localRgroup.grouplist = "127.0.0.1:8091"

@RestController
public class DemoController {
	@Autowired
	private DemoFeignClient demoFeignClient;
	
	@Autowired
	private DemoFeignClient2 demoFeignClient2;
	@GlobalTransactional(timeoutMills = 300000, name = "spring-cloud-demo-tx")
	@GetMapping("/getdemo")
	public String demo() {
		
		// 调用A 服务  简单save
		ResponseData<Integer> result = demoFeignClient.insertService("test",1);
		if(result.getStatus()==400) {
			System.out.println(result+"+++++++++++++++++++++++++++++++++++++++");
			throw new RuntimeException("this is error1");
		}
	
		// 调用B 服务。报错测试A 服务回滚
		ResponseData<Integer>  result2 = demoFeignClient2.saveService();
	
		if(result2.getStatus()==400) {
			System.out.println(result2+"+++++++++++++++++++++++++++++++++++++++");
			throw new RuntimeException("this is error2");
		}

		return "SUCCESS";
	}
}

@Configuration
public class DatabaseConfiguration {

	
	@Bean(destroyMethod = "close", initMethod = "init")
	@ConfigurationProperties(prefix="spring.datasource")
	public DruidDataSource druidDataSource() {

		return new DruidDataSource();
	}
	
	
	@Bean
	public DataSourceProxy dataSourceProxy(DruidDataSource druidDataSource) {
	
		return new DataSourceProxy(druidDataSource);
	}
	

    @Bean
    public SqlSessionFactory sqlSessionFactory(DataSourceProxy dataSourceProxy) throws Exception {
        SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
        factoryBean.setDataSource(dataSourceProxy);    
        return factoryBean.getObject();
    }
}

private static final String REGISTRY_CONF = "registry.conf";
public static final Configuration FILE_INSTANCE = new FileConfiguration(REGISTRY_CONF);

@Bean
@ConfigurationProperties(prefix = "spring.datasource")
public DruidDataSource druidDataSource() {
    DruidDataSource druidDataSource = new DruidDataSource();
    return druidDataSource;
}

@Primary
@Bean("dataSource")
public DataSourceProxy dataSource(DruidDataSource druidDataSource) {
    return new DataSourceProxy(druidDataSource);
}

@Configuration
@EnableConfigurationProperties({FescarProperties.class})
public class GlobalTransactionAutoConfiguration {
    private final ApplicationContext applicationContext;
    private final FescarProperties fescarProperties;

    public GlobalTransactionAutoConfiguration(ApplicationContext applicationContext, FescarProperties fescarProperties) {
        this.applicationContext = applicationContext;
        this.fescarProperties = fescarProperties;
    }

	/**
	* 示例化GlobalTransactionScanner
	* scanner为client初始化的发起类
	*/
    @Bean
    public GlobalTransactionScanner globalTransactionScanner() {
        String applicationName = this.applicationContext.getEnvironment().getProperty("spring.application.name");
        String txServiceGroup = this.fescarProperties.getTxServiceGroup();
        if (StringUtils.isEmpty(txServiceGroup)) {
            txServiceGroup = applicationName + "-fescar-service-group";
            this.fescarProperties.setTxServiceGroup(txServiceGroup);
        }
		
        return new GlobalTransactionScanner(applicationName, txServiceGroup);
    }
}

@ConfigurationProperties("spring.cloud.alibaba.fescar")
public class FescarProperties {
    private String txServiceGroup;

    public FescarProperties() {
    }

    public String getTxServiceGroup() {
        return this.txServiceGroup;
    }

    public void setTxServiceGroup(String txServiceGroup) {
        this.txServiceGroup = txServiceGroup;
    }
}

private void initClient() {
    if (StringUtils.isNullOrEmpty(applicationId) || StringUtils.isNullOrEmpty(txServiceGroup)) {
        throw new IllegalArgumentException(
            "applicationId: " + applicationId + ", txServiceGroup: " + txServiceGroup);
    }
    //init TM
    TMClient.init(applicationId, txServiceGroup);

    //init RM
    RMClient.init(applicationId, txServiceGroup);
  
}

2019-04-09 13:42:57.417  INFO 93715 --- [imeoutChecker_1] c.a.f.c.rpc.netty.NettyPoolableFactory   : NettyPool create channel to {"address":"127.0.0.1:8091","message":{"applicationId":"business-service","byteBuffer":{"char":"\u0000","direct":false,"double":0.0,"float":0.0,"int":0,"long":0,"readOnly":false,"short":0},"transactionServiceGroup":"my_test_tx_group","typeCode":101,"version":"0.4.1"},"transactionRole":"TMROLE"}
2019-04-09 13:42:57.505  INFO 93715 --- [imeoutChecker_1] c.a.f.c.rpc.netty.NettyPoolableFactory   : NettyPool create channel to {"address":"127.0.0.1:8091","message":{"applicationId":"business-service","byteBuffer":{"char":"\u0000","direct":false,"double":0.0,"float":0.0,"int":0,"long":0,"readOnly":false,"short":0},"transactionServiceGroup":"my_test_tx_group","typeCode":103,"version":"0.4.1"},"transactionRole":"RMROLE"}
2019-04-09 13:42:57.629 DEBUG 93715 --- [lector_TMROLE_1] c.a.f.c.rpc.netty.MessageCodecHandler    : Send:RegisterTMRequest{applicationId='business-service', transactionServiceGroup='my_test_tx_group'}
2019-04-09 13:42:57.629 DEBUG 93715 --- [lector_RMROLE_1] c.a.f.c.rpc.netty.MessageCodecHandler    : Send:RegisterRMRequest{resourceIds='null', applicationId='business-service', transactionServiceGroup='my_test_tx_group'}
2019-04-09 13:42:57.699 DEBUG 93715 --- [lector_RMROLE_1] c.a.f.c.rpc.netty.MessageCodecHandler    : Receive:version=0.4.1,extraData=null,identified=true,resultCode=null,msg=null,messageId:1
2019-04-09 13:42:57.699 DEBUG 93715 --- [lector_TMROLE_1] c.a.f.c.rpc.netty.MessageCodecHandler    : Receive:version=0.4.1,extraData=null,identified=true,resultCode=null,msg=null,messageId:2
2019-04-09 13:42:57.701 DEBUG 93715 --- [lector_RMROLE_1] c.a.f.c.rpc.netty.AbstractRpcRemoting    : com.alibaba.fescar.core.rpc.netty.RmRpcClient@3b06d101 msgId:1, future :com.alibaba.fescar.core.protocol.MessageFuture@28bb1abd, body:version=0.4.1,extraData=null,identified=true,resultCode=null,msg=null
2019-04-09 13:42:57.701 DEBUG 93715 --- [lector_TMROLE_1] c.a.f.c.rpc.netty.AbstractRpcRemoting    : com.alibaba.fescar.core.rpc.netty.TmRpcClient@65fc3fb7 msgId:2, future :com.alibaba.fescar.core.protocol.MessageFuture@9a1e3df, body:version=0.4.1,extraData=null,identified=true,resultCode=null,msg=null
2019-04-09 13:42:57.710  INFO 93715 --- [imeoutChecker_1] c.a.fescar.core.rpc.netty.RmRpcClient    : register RM success. server version:0.4.1,channel:[id: 0xe6468995, L:/127.0.0.1:57397 - R:/127.0.0.1:8091]
2019-04-09 13:42:57.710  INFO 93715 --- [imeoutChecker_1] c.a.f.c.rpc.netty.NettyPoolableFactory   : register success, cost 114 ms, version:0.4.1,role:TMROLE,channel:[id: 0xd22fe0c5, L:/127.0.0.1:57398 - R:/127.0.0.1:8091]
2019-04-09 13:42:57.711  INFO 93715 --- [imeoutChecker_1] c.a.f.c.rpc.netty.NettyPoolableFactory   : register success, cost 125 ms, version:0.4.1,role:RMROLE,channel:[id: 0xe6468995, L:/127.0.0.1:57397 - R:/127.0.0.1:8091]

@Service
public class BusinessService {

    @Autowired
    private StorageFeignClient storageFeignClient;
    @Autowired
    private OrderFeignClient orderFeignClient;

    @GlobalTransactional
    public void purchase(String userId, String commodityCode, int orderCount){
        storageFeignClient.deduct(commodityCode, orderCount);

        orderFeignClient.create(userId, commodityCode, orderCount);
    }
}

/**
 * AOP拦截方法调用
 */
@Override
public Object invoke(final MethodInvocation methodInvocation) throws Throwable {
    Class<?> targetClass = (methodInvocation.getThis() != null ? AopUtils.getTargetClass(methodInvocation.getThis()) : null);
    Method specificMethod = ClassUtils.getMostSpecificMethod(methodInvocation.getMethod(), targetClass);
    final Method method = BridgeMethodResolver.findBridgedMethod(specificMethod);

	//获取方法GlobalTransactional注解
    final GlobalTransactional globalTransactionalAnnotation = getAnnotation(method, GlobalTransactional.class);
    final GlobalLock globalLockAnnotation = getAnnotation(method, GlobalLock.class);
    
    //如果方法有GlobalTransactional注解，则拦截到相应方法处理
    if (globalTransactionalAnnotation != null) {
        return handleGlobalTransaction(methodInvocation, globalTransactionalAnnotation);
    } else if (globalLockAnnotation != null) {
        return handleGlobalLock(methodInvocation);
    } else {
        return methodInvocation.proceed();
    }
}

public Object execute(TransactionalExecutor business) throws TransactionalExecutor.ExecutionException {
    // 1. get or create a transaction
    GlobalTransaction tx = GlobalTransactionContext.getCurrentOrCreate();

    try {
        // 2. begin transaction
        try {
            triggerBeforeBegin();
            tx.begin(business.timeout(), business.name());
            triggerAfterBegin();
        } catch (TransactionException txe) {
            throw new TransactionalExecutor.ExecutionException(tx, txe,
                TransactionalExecutor.Code.BeginFailure);
        }
        Object rs = null;
        try {
            // Do Your Business
            rs = business.execute();
        } catch (Throwable ex) {
            // 3. any business exception, rollback.
            try {
                triggerBeforeRollback();
                tx.rollback();
                triggerAfterRollback();
                // 3.1 Successfully rolled back
                throw new TransactionalExecutor.ExecutionException(tx, TransactionalExecutor.Code.RollbackDone, ex);
            } catch (TransactionException txe) {
                // 3.2 Failed to rollback
                throw new TransactionalExecutor.ExecutionException(tx, txe,
                    TransactionalExecutor.Code.RollbackFailure, ex);
            }
        }
        // 4. everything is fine, commit.
        try {
            triggerBeforeCommit();
            tx.commit();
            triggerAfterCommit();
        } catch (TransactionException txe) {
            // 4.1 Failed to commit
            throw new TransactionalExecutor.ExecutionException(tx, txe,
                TransactionalExecutor.Code.CommitFailure);
        }
        return rs;
    } finally {
        //5. clear
        triggerAfterCompletion();
        cleanUp();
    }
}