为什么retryOnConnectionFailure（true）是OkHttp错误的解决方案：java.io.ioException：意外的流结束

Question

当我发现这个的时候，我已经有一段时间了。使用swankjesse提供的解决方案后，错误消失了。我只是不明白为什么这是一个解决办法。我在网上找不到任何解释这种方法解决错误的原因的东西。

Answer 1

此标志允许OkHttpClient在某些条件为真时多次重试请求，这意味着已知该请求是安全的。如果没有这个标志，客户端将立即返回错误，如果以及何时重试，客户端可能会返回dcide。

  private fun isRecoverable(e: IOException, requestSendStarted: Boolean): Boolean {
    // If there was a protocol problem, don't recover.
    if (e is ProtocolException) {
      return false
    }

    // If there was an interruption don't recover, but if there was a timeout connecting to a route
    // we should try the next route (if there is one).
    if (e is InterruptedIOException) {
      return e is SocketTimeoutException && !requestSendStarted
    }

    // Look for known client-side or negotiation errors that are unlikely to be fixed by trying
    // again with a different route.
    if (e is SSLHandshakeException) {
      // If the problem was a CertificateException from the X509TrustManager,
      // do not retry.
      if (e.cause is CertificateException) {
        return false
      }
    }
    if (e is SSLPeerUnverifiedException) {
      // e.g. a certificate pinning error.
      return false
    }
    // An example of one we might want to retry with a different route is a problem connecting to a
    // proxy and would manifest as a standard IOException. Unless it is one we know we should not
    // retry, we return true and try a new route.
    return true
  }

在最简单的情况下，如果我们没有开始发送请求，那么我们知道重试一定是安全的。类似地，某些响应代码，如408，表明服务器还没有开始任何工作，所以我们可以再试一次。