Question

我正在尝试在未收到响应后实施请求重试。我正在Httpclient教程中阅读它。 HttpRequestRetryHandler只被调用一次，然后抛出异常。我在这做错了什么？

更新
我在SocketTimeoutException的异常处理中添加了一个if条件但是那里该怎么办？我该如何重试？

private void setRetry(int executionCount)
    {
        myRetryHandler = new HttpRequestRetryHandler() {

            public boolean retryRequest(IOException exception,int executionCount,HttpContext context) {

                if (executionCount >= 4) {
                    // Do not retry if over max retry count
                    System.out.println("retry count");
                    return false;
                }
                if (exception instanceof NoHttpResponseException) {
                    System.out.println("NoHttpResponseException exception");// Retry if the server dropped connection on us
                    return true;
                }
                if (exception instanceof SSLHandshakeException) {
                    // Do not retry on SSL handshake exception
                    System.out.println("SSLHandshakeException exception");
                    return false;
                }
                if (exception instanceof java.net.SocketTimeoutException) {
                  // Do not retry on SSL handshake exception
                  System.out.println("java.net.SocketTimeoutException exception");
                  return false;
                }
                HttpRequest request = (HttpRequest) context.getAttribute( ExecutionContext.HTTP_REQUEST);
                boolean idempotent = !(request instanceof HttpEntityEnclosingRequest); 
                if (idempotent) {
                    System.out.println("idempotent exception");
                    // Retry if the request is considered idempotent 
                    return true;
                }
                return false;
            }

        };
    }
    public  String postHttpReqest(int retries,
                                  int socketTimeoutMillis,
                                  int isSSL,
                                  String target,
                                  String url,
                                  String base_url,
                                  int port,
                                  LinkedHashMap<String, String> lHashMapParams) throws Exception 
    {


        HttpParams httpParams = new BasicHttpParams();
        HttpConnectionParams.setConnectionTimeout(httpParams, 50000);
        HttpConnectionParams.setSoTimeout(httpParams, socketTimeoutMillis);         
        defaulthttpclient = new DefaultHttpClient(httpParams);

        setRetry(retries);  // here i set the handler 
        defaulthttpclient.setHttpRequestRetryHandler(myRetryHandler);

        String line = "";

        List<BasicNameValuePair> params = new ArrayList<BasicNameValuePair>();
        for (String key : lHashMapParams.keySet()) {
            String val = lHashMapParams.get(key);
            params.add(new BasicNameValuePair(key,val));

        }

        UrlEncodedFormEntity query = new UrlEncodedFormEntity(params); 
        HttpPost httppost = new HttpPost(url+":"+Integer.toString(port)+"//"+base_url);
        httppost.setEntity(query);
        HttpResponse response_ = defaulthttpclient.execute(httppost);
        HttpEntity entity = response_.getEntity();

        if (entity != null) {
            line = EntityUtils.toString(entity);
            System.out.println(line);

        }

        return line;
    }

在服务器中，我设置了断点，因此它将保持连接并且不会返回响应。我在Httpclient中遇到的错误：

java.net.SocketTimeoutException: Read timed out
    at java.net.SocketInputStream.socketRead0(Native Method)
    at java.net.SocketInputStream.read(SocketInputStream.java:129)
    at org.apache.http.impl.io.AbstractSessionInputBuffer.fillBuffer(AbstractSessionInputBuffer.java:149)
    at org.apache.http.impl.io.SocketInputBuffer.fillBuffer(SocketInputBuffer.java:110)
    at org.apache.http.impl.io.AbstractSessionInputBuffer.readLine(AbstractSessionInputBuffer.java:260)
    at org.apache.http.impl.conn.LoggingSessionInputBuffer.readLine(LoggingSessionInputBuffer.java:115)
    at org.apache.http.impl.conn.DefaultResponseParser.parseHead(DefaultResponseParser.java:98)
    at org.apache.http.impl.io.AbstractMessageParser.parse(AbstractMessageParser.java:252)
    at org.apache.http.impl.AbstractHttpClientConnection.receiveResponseHeader(AbstractHttpClientConnection.java:281)
    at org.apache.http.impl.conn.DefaultClientConnection.receiveResponseHeader(DefaultClientConnection.java:247)
    at org.apache.http.impl.conn.AbstractClientConnAdapter.receiveResponseHeader(AbstractClientConnAdapter.java:219)
    at org.apache.http.protocol.HttpRequestExecutor.doReceiveResponse(HttpRequestExecutor.java:298)
    at org.apache.http.protocol.HttpRequestExecutor.execute(HttpRequestExecutor.java:125)
    at org.apache.http.impl.client.DefaultRequestDirector.tryExecute(DefaultRequestDirector.java:633)
    at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:454)
    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:820)
    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:754)
    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:732)
    at com.fts.lb.connector.ut.HttpClientImpl.postHttpReqest(HttpClientImpl.java:183)

Answer 1

嗯..你的RetryHandler专门为SocketTimeoutException返回false。所以我希望它能在100％的时间内抛出异常，就是这样。

如果您希望在客户端在收到响应之前超时重试请求，那么您需要让RetyrHandler为SocketTimeOutExceptions返回true。您可能还想在重试之前增加SocketTimeOut。

Answer 2

谷歌有点我在HttpClient 4.1客户端中找到了这个bug（仅限在Windows上）。

对于我的问题，我已经使用了最新的4.1.1，但也许我必须实现retryHandler。

我希望它会有所帮助。

Java Httpclient HttpRequestRetryHandler不起作用。如何实施重试？

2 个答案: