AsyncHttpClient exception異常源碼流程解析

更新時間：2023年12月11日 08:36:16 作者：codecraft

這篇文章主要為大家介紹了AsyncHttpClient的exception源碼流程解析，有需要的朋友可以借鑒參考下，希望能夠有所幫助，祝大家多多進步，早日升職加薪

序

本文主要研究一下AsyncHttpClient的exception

ChannelClosedException

org/asynchttpclient/exception/ChannelClosedException.java

public final class ChannelClosedException extends IOException {
  public static final ChannelClosedException INSTANCE = unknownStackTrace(new ChannelClosedException(), ChannelClosedException.class, "INSTANCE");
  private ChannelClosedException() {
    super("Channel closed");
  }
}

ChannelClosedException用于表示Channel closed的異常

handleUnexpectedClosedChannel

org/asynchttpclient/netty/request/NettyRequestSender.java

public void handleUnexpectedClosedChannel(Channel channel, NettyResponseFuture<?> future) {
    if (Channels.isActiveTokenSet(channel)) {
      if (future.isDone()) {
        channelManager.closeChannel(channel);
      } else if (future.incrementRetryAndCheck() && retry(future)) {
        future.pendingException = null;
      } else {
        abort(channel, future,
                future.pendingException != null ? future.pendingException : RemotelyClosedException.INSTANCE);
      }
    }
  }

NettyRequestSender定義了handleUnexpectedClosedChannel方法，它會關(guān)閉或abort當前的channel

PoolAlreadyClosedException

org/asynchttpclient/exception/PoolAlreadyClosedException.java

public class PoolAlreadyClosedException extends IOException {
  public static final PoolAlreadyClosedException INSTANCE = unknownStackTrace(new PoolAlreadyClosedException(), PoolAlreadyClosedException.class, "INSTANCE");
  private PoolAlreadyClosedException() {
    super("Pool is already closed");
  }
}

PoolAlreadyClosedException用于表示連接池已經(jīng)關(guān)閉的異常

sendRequestWithNewChannel

org/asynchttpclient/netty/request/NettyRequestSender.java

private <T> ListenableFuture<T> sendRequestWithNewChannel(Request request,
                                                            ProxyServer proxy,
                                                            NettyResponseFuture<T> future,
                                                            AsyncHandler<T> asyncHandler) {
    // some headers are only set when performing the first request
    HttpHeaders headers = future.getNettyRequest().getHttpRequest().headers();
    Realm realm = future.getRealm();
    Realm proxyRealm = future.getProxyRealm();
    requestFactory.addAuthorizationHeader(headers, perConnectionAuthorizationHeader(request, proxy, realm));
    requestFactory.setProxyAuthorizationHeader(headers, perConnectionProxyAuthorizationHeader(request, proxyRealm));
    future.setInAuth(realm != null && realm.isUsePreemptiveAuth() && realm.getScheme() != AuthScheme.NTLM);
    future.setInProxyAuth(
            proxyRealm != null && proxyRealm.isUsePreemptiveAuth() && proxyRealm.getScheme() != AuthScheme.NTLM);
    try {
      if (!channelManager.isOpen()) {
        throw PoolAlreadyClosedException.INSTANCE;
      }
      // Do not throw an exception when we need an extra connection for a
      // redirect.
      future.acquirePartitionLockLazily();
    } catch (Throwable t) {
      abort(null, future, getCause(t));
      // exit and don't try to resolve address
      return future;
    }
    //......
}

sendRequestWithNewChannel在channelManager非open的時候會拋出PoolAlreadyClosedException

RemotelyClosedException

org/asynchttpclient/exception/RemotelyClosedException.java

public final class RemotelyClosedException extends IOException {
  public static final RemotelyClosedException INSTANCE = unknownStackTrace(new RemotelyClosedException(), RemotelyClosedException.class, "INSTANCE");
  RemotelyClosedException() {
    super("Remotely closed");
  }
}

RemotelyClosedException用于表示Remotely closed的異常

handleUnexpectedClosedChannel

org/asynchttpclient/netty/request/NettyRequestSender.java

public void handleUnexpectedClosedChannel(Channel channel, NettyResponseFuture&lt;?&gt; future) {
    if (Channels.isActiveTokenSet(channel)) {
      if (future.isDone()) {
        channelManager.closeChannel(channel);
      } else if (future.incrementRetryAndCheck() &amp;&amp; retry(future)) {
        future.pendingException = null;
      } else {
        abort(channel, future,
                future.pendingException != null ? future.pendingException : RemotelyClosedException.INSTANCE);
      }
    }
  }

NettyRequestSender的handleUnexpectedClosedChannel的時候，對于future未完成也沒有重試的時候會執(zhí)行abort，并拋出RemotelyClosedException

TooManyConnectionsException

org/asynchttpclient/exception/TooManyConnectionsException.java

public class TooManyConnectionsException extends IOException {
  public TooManyConnectionsException(int max) {
    super("Too many connections: " + max);
  }
}

TooManyConnectionsException用于表示全局連接超過限制的異常

TooManyConnectionsPerHostException

org/asynchttpclient/exception/TooManyConnectionsPerHostException.java

public class TooManyConnectionsPerHostException extends IOException {
  public TooManyConnectionsPerHostException(int max) {
    super("Too many connections: " + max);
  }
}

TooManyConnectionsPerHostException用于表示連接超出單host限制的異常

acquireChannelLock

org/asynchttpclient/netty/channel/ConnectionSemaphore.java

public void acquireChannelLock(Object partitionKey) throws IOException {
    if (!tryAcquireGlobal())
      throw tooManyConnections;
    if (!tryAcquirePerHost(partitionKey)) {
      freeChannels.release();
      throw tooManyConnectionsPerHost;
    }
  }

acquireChannelLock方法在全局連接超出限制時拋出tooManyConnections，在單host連接超出限制時拋出tooManyConnectionsPerHost

小結(jié)

AsyncHttpClient一共定義了五個異常，它們都繼承了IOException，分別是ChannelClosedException、PoolAlreadyClosedException、RemotelyClosedException、TooManyConnectionsException、TooManyConnectionsPerHostException。

以上就是AsyncHttpClient的exception的詳細內(nèi)容，更多關(guān)于AsyncHttpClient的exception的資料請關(guān)注腳本之家其它相關(guān)文章！

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