How to use

RpcException

in

com.alibaba.dubbo.rpc

public <T> Invoker<T> select(List<Invoker<T>> invokers, URL url, Invocation invocation) throws RpcException {
  if (invokers == null || invokers.isEmpty()) {
    throw new RpcException("No invoker is found!");
  }
  int lengthOfInvokerList = invokers == null ? 0 : invokers.size();
  return invokers.get(random.nextInt(lengthOfInvokerList));
}

static void onError(Throwable error, Span span) {
 span.error(error);
 if (error instanceof RpcException) {
  span.tag("dubbo.error_code", Integer.toString(((RpcException) error).getCode()));
 }
}

@SuppressWarnings({"unchecked", "rawtypes"})
private Result doMockInvoke(Invocation invocation, RpcException e) {
  Result result = null;
  Invoker<T> minvoker;
  List<Invoker<T>> mockInvokers = selectMockInvoker(invocation);
  if (mockInvokers == null || mockInvokers.isEmpty()) {
    minvoker = (Invoker<T>) new MockInvoker(directory.getUrl());
  } else {
    minvoker = mockInvokers.get(0);
  }
  try {
    result = minvoker.invoke(invocation);
  } catch (RpcException me) {
    if (me.isBiz()) {
      result = new RpcResult(me.getCause());
    } else {
      throw new RpcException(me.getCode(), getMockExceptionMessage(e, me), me.getCause());
    }
  } catch (Throwable me) {
    throw new RpcException(getMockExceptionMessage(e, me), me.getCause());
  }
  return result;
}

  exception = new RpcException("Failed to register service to redis registry. registry: " + entry.getKey() + ", service: " + url + ", cause: " + t.getMessage(), t);
  logger.warn(exception.getMessage(), exception);
} else {
  throw exception;

protected RpcException getRpcException(Class<?> type, URL url, Invocation invocation, Throwable e) {
  RpcException re = new RpcException("Failed to invoke remote service: " + type + ", method: "
      + invocation.getMethodName() + ", cause: " + e.getMessage(), e);
  re.setCode(getErrorCode(e));
  return re;
}

  public Result doInvoke(Invocation invocation, List<Invoker<T>> invokers, LoadBalance loadbalance) throws RpcException {
    checkInvokers(invokers, invocation);
    Invoker<T> invoker = select(loadbalance, invocation, invokers, null);
    try {
      return invoker.invoke(invocation);
    } catch (Throwable e) {
      if (e instanceof RpcException && ((RpcException)e).isBiz()) { // biz exception.
        throw (RpcException) e;
      }
      throw new RpcException(e instanceof RpcException ? ((RpcException)e).getCode() : 0, "Failfast invoke providers " + invoker.getUrl() + " " + loadbalance.getClass().getSimpleName() + " select from all providers " + invokers + " for service " + getInterface().getName() + " method " + invocation.getMethodName() + " on consumer " + NetUtils.getLocalHost() + " use dubbo version " + Version.getVersion() + ", but no luck to perform the invocation. Last error is: " + e.getMessage(), e.getCause() != null ? e.getCause() : e);
    }
  }
}

if (ret instanceof Throwable) {
  Throwable e = (Throwable) ret;
  throw new RpcException(e instanceof RpcException ? ((RpcException)e).getCode() : 0, "Failed to forking invoke provider " + selected + ", but no luck to perform the invocation. Last error is: " + e.getMessage(), e.getCause() != null ? e.getCause() : e);
throw new RpcException("Failed to forking invoke provider " + selected + ", but no luck to perform the invocation. Last error is: " + e.getMessage(), e);

public Result invoke(Invocation inv) throws RpcException {
  if(destroyed) {
    throw new RpcException("Rpc invoker for service " + this + " on consumer " + NetUtils.getLocalHost() 
                    + " use dubbo version " + Version.getVersion()
                    + " is DESTROYED, can not be invoked any more!");
    } else {
      if (te instanceof RpcException) {
        ((RpcException) te).setCode(RpcException.BIZ_EXCEPTION);
    if (e.isBiz()) {
      return new RpcResult(e);
    } else {

  @Override
  protected Result doInvoke(Invocation invocation) throws Throwable {
    try {
      Result result = target.invoke(invocation);
      Throwable e = result.getException();
      if (e != null) {
        for (Class<?> rpcException : rpcExceptions) {
          if (rpcException.isAssignableFrom(e.getClass())) {
            throw getRpcException(type, url, invocation, e);
          }
        }
      }
      return result;
    } catch (RpcException e) {
      if (e.getCode() == RpcException.UNKNOWN_EXCEPTION) {
        e.setCode(getErrorCode(e.getCause()));
      }
      throw e;
    } catch (Throwable e) {
      throw getRpcException(type, url, invocation, e);
    }
  }
};

@Override
public Response toResponse(RpcException e) {
  // TODO do more sophisticated exception handling and output
  if (e.getCause() instanceof ConstraintViolationException) {
    return handleConstraintViolationException((ConstraintViolationException) e.getCause());
  }
  // we may want to avoid exposing the dubbo exception details to certain clients
  // TODO for now just do plain text output
  return Response.status(Response.Status.INTERNAL_SERVER_ERROR).entity("Internal server error: " + e.getMessage()).type(ContentType.TEXT_PLAIN_UTF_8).build();
}

} else {
  if (te instanceof RpcException) {
    ((RpcException) te).setCode(RpcException.BIZ_EXCEPTION);
if (e.isBiz()) {
  return new RpcResult(e);
} else {

private Result wrapBreakerInvoke(Invoker<?> invoker, Invocation invocation) throws RpcException {
  //首先检查是否需要进入服务降级流程
  if(checkNeedCircuitBreak(invoker, invocation)){
    logger.info("[{}] activate the circuit break for url [{}],invoke method [{}]",localHost,invoker.getUrl(),invocation.getMethodName());
    //进入服务降级
    return doCircuitBreak(invoker, invocation);
  }
  try{
    Result result = invoker.invoke(invocation);
    //将该服务从服务降级中恢复出来
    toBeNormal(invoker, invocation);
    return result;
  }catch (RpcException e){
    //如果是请求超时或者网络异常，进行异常统计
    if(!e.isBiz()){
      caughtException(invoker,invocation,e);
    }
    throw e;
  }
}

@Override
public T get() throws InterruptedException, ExecutionException {
  throw new ExecutionException(e.getCause());
}

public Result invoke(Invoker<?> invoker, Invocation invocation) throws RpcException {
  URL url = invoker.getUrl();
  String spanName = url.getServiceInterface() + "." + invocation.getMethodName();
  Span newSpan = tracer.createSpan(spanName);
  try {
    dubboSpanInjector.inject(newSpan, RpcContext.getContext());
    newSpan.logEvent(Span.CLIENT_SEND);
    return invoker.invoke(invocation);
  } catch (RpcException e) {
    newSpan.tag("error", e.getMessage());
    throw e;
  } finally {
    if (tracer.isTracing()) {
      tracer.getCurrentSpan().logEvent(Span.CLIENT_RECV);
      tracer.close(tracer.getCurrentSpan());
    }
  }
}

  @SuppressWarnings({ "unchecked", "rawtypes" })
  private Result doMockInvoke(Invocation invocation,RpcException e){
    Result result = null;
    Invoker<T> minvoker ;
    
    List<Invoker<T>> mockInvokers = selectMockInvoker(invocation);
    if (mockInvokers == null || mockInvokers.size() == 0){
      minvoker = (Invoker<T>) new MockInvoker(directory.getUrl());
    } else {
      minvoker = mockInvokers.get(0);
    }
    try {
      result = minvoker.invoke(invocation);
    } catch (RpcException me) {
      if (me.isBiz()) {
        result = new RpcResult(me.getCause());
      } else {
        throw new RpcException(me.getCode(), getMockExceptionMessage(e, me), me.getCause());
      }
//            
    } catch (Throwable me) {
      throw new RpcException(getMockExceptionMessage(e, me), me.getCause());
    }
    return result;
  }
   

  exception = new RpcException("Failed to register service to redis registry. registry: " + entry.getKey() + ", service: " + url + ", cause: " + t.getMessage(), t);
  logger.warn(exception.getMessage(), exception);
} else {
  throw exception;

protected RpcException getRpcException(Class<?> type, URL url, Invocation invocation, Throwable e) {
  RpcException re = new RpcException("Failed to invoke remote service: " + type + ", method: "
      + invocation.getMethodName() + ", cause: " + e.getMessage(), e);
  re.setCode(getErrorCode(e));
  return re;
}

  public Result doInvoke(Invocation invocation, List<Invoker<T>> invokers, LoadBalance loadbalance) throws RpcException {
    checkInvokers(invokers, invocation);
    Invoker<T> invoker = select(loadbalance, invocation, invokers, null);
    try {
      return invoker.invoke(invocation);
    } catch (Throwable e) {
      if (e instanceof RpcException && ((RpcException)e).isBiz()) { // biz exception.
        throw (RpcException) e;
      }
      throw new RpcException(e instanceof RpcException ? ((RpcException)e).getCode() : 0, "Failfast invoke providers " + invoker.getUrl() + " " + loadbalance.getClass().getSimpleName() + " select from all providers " + invokers + " for service " + getInterface().getName() + " method " + invocation.getMethodName() + " on consumer " + NetUtils.getLocalHost() + " use dubbo version " + Version.getVersion() + ", but no luck to perform the invocation. Last error is: " + e.getMessage(), e.getCause() != null ? e.getCause() : e);
    }
  }
}

if (ret instanceof Throwable) {
  Throwable e = (Throwable) ret;
  throw new RpcException(e instanceof RpcException ? ((RpcException)e).getCode() : 0, "Failed to forking invoke provider " + selected + ", but no luck to perform the invocation. Last error is: " + e.getMessage(), e.getCause() != null ? e.getCause() : e);
throw new RpcException("Failed to forking invoke provider " + selected + ", but no luck to perform the invocation. Last error is: " + e.getMessage(), e);

public Result invoke(Invocation inv) throws RpcException {
  if(destroyed) {
    throw new RpcException("Rpc invoker for service " + this + " on consumer " + NetUtils.getLocalHost() 
                    + " use dubbo version " + Version.getVersion()
                    + " is DESTROYED, can not be invoked any more!");
    } else {
      if (te instanceof RpcException) {
        ((RpcException) te).setCode(RpcException.BIZ_EXCEPTION);
    if (e.isBiz()) {
      return new RpcResult(e);
    } else {