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社区首页 >问答首页 >Java HttpServer读取超时，来自同一应用的后续请求彼此太近

问Java HttpServer读取超时，来自同一应用的后续请求彼此太近
EN

Stack Overflow用户
提问于 2018-06-13 05:08:09
回答 1查看 957关注 0票数 0

由于java HttpServer的一个问题，我快疯了。我创建具有上下文等功能的服务器，然后从客户端应用程序使用URLConnection和InputStream连接到服务器。

问题是，当客户端执行更多的后续请求时，它经常(没有明显的逻辑)获得读取超时。为了避免这种情况，我必须设置一个睡眠(5000)(为什么是5000？因为低于5000，它仍然会从一个连接和下一个连接给出超时。

我已经尝试过使用Executor(同时使用Executors.newCachedThreadPool()和Executors.newFixedThreadPool(10)，，但什么也没有使用。

另一件奇怪的事情是使用两个客户端：

  1. Client 1: first request = ok
  2. Client 2: first request = ok
  3. WAIT first SECONDS
  4. Client 1: second request = ok
  5. Client 1: third request = freeze (参见下面的代码)，然后发送
  6. 2: second request = ok (当client 1仍在尝试并超时时)

<>G225

所以..。问题似乎与特定的客户端实例有关

这里有一些代码

服务器

代码语言：javascript
复制
try {
        cryptex = new ServerCryptex();
        final Executor multi = Executors.newCachedThreadPool();
        server = HttpServer.create(new InetSocketAddress(8888), 50);

        addContexts();

        server.setExecutor(multi);
        server.start();


    } catch (IOException ex) {
        Logger.getLogger(MyHttpServer.class.getName()).log(Level.SEVERE, null, ex);
    }

上下文是通过添加的

代码语言：javascript
复制
server.createContext("/empty", new HttpHandler_Empty(this));

等

客户端

这是执行请求的函数

代码语言：javascript
复制
 public byte[] performRequest(HashMap<String, String> params, String host, int port, String handler, boolean isConnectionEncrypted) throws IOException, InterruptedException {
    URL url = composeUrl(params, host, port, handler, isConnectionEncrypted);
    URLConnection con = url.openConnection();
    con.setConnectTimeout(300);
    con.setReadTimeout(7000);
    InputStream is = null;

    **NO PROBLEM UNTIL HERE**

    for (int i = 0; i < 5; i++) {
        try {
            System.out.println("open the stream, try #" + i);

            **TIMEOUT ON THE NEXT LINE**

            is = con.getInputStream();
            break;
        } catch (java.net.SocketTimeoutException ex) {

            **I THOUGHT TO USE THIS WAY TO TRY 5 TIMES THE CONNECTION BEFORE GIVING ERROR TO THE USER, BUT NOTHING. **

            sleep(500);
            if (i == 4) {
                throw ex;
            }
        }
    }
    String reply = readReply(is);
    System.out.println("read reply:" + reply);
    if (isConnectionEncrypted) {
        return cryptex.decrypt(reply);
    } else {
        return reply.getBytes();
    }

}

真正的代码(没有5次尝试的代码)

代码语言：javascript
复制
public byte[] performRequest(HashMap<String, String> params, String host, int port, String handler, boolean isConnectionEncrypted) throws IOException, InterruptedException {
    URL url = composeUrl(params, host, port, handler, isConnectionEncrypted);
    HttpURLConnection con = (HttpURLConnection) url.openConnection();
    con.setConnectTimeout(300);
    con.setReadTimeout(2000);

    System.out.println("open the stream");
    InputStream is = con.getInputStream();

    String reply = readReply(is);
    System.out.println("risposta letta:" + reply);
    if (isConnectionEncrypted) {
        return cryptex.decrypt(reply);
    } else {
        return reply.getBytes();
    }

}

和错误

代码语言：javascript
复制
giu 12, 2018 10:58:01 PM gui.Client_GUI aggiornaUdg
GRAVE: null 
java.net.SocketTimeoutException: Read timed out
at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.socketRead(SocketInputStream.java:116)
at java.net.SocketInputStream.read(SocketInputStream.java:170)
at java.net.SocketInputStream.read(SocketInputStream.java:141)
at java.io.BufferedInputStream.fill(BufferedInputStream.java:246)
at java.io.BufferedInputStream.read1(BufferedInputStream.java:286)
at java.io.BufferedInputStream.read(BufferedInputStream.java:345)
at sun.net.www.http.HttpClient.parseHTTPHeader(HttpClient.java:704)
at sun.net.www.http.HttpClient.parseHTTP(HttpClient.java:647)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1569)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1474)
at net.ClientConnector.performRequest(ClientConnector.java:96)
at net.ClientConnector.checkKey(ClientConnector.java:43)
at net.Client.getUDG(Client.java:56)
at gui.Client_GUI.aggiornaUdg(Client_GUI.java:2407)
at gui.Client_GUI.jButton1ActionPerformed(Client_GUI.java:1917)
at gui.Client_GUI.access$000(Client_GUI.java:53)
at gui.Client_GUI$1.actionPerformed(Client_GUI.java:390)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2348)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
at java.awt.Component.processMouseEvent(Component.java:6533)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
at java.awt.Component.processEvent(Component.java:6298)
at java.awt.Container.processEvent(Container.java:2236)
at java.awt.Component.dispatchEventImpl(Component.java:4889)
at java.awt.Container.dispatchEventImpl(Container.java:2294)
at java.awt.Component.dispatchEvent(Component.java:4711)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4888)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4525)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4466)
at java.awt.Container.dispatchEventImpl(Container.java:2280)
at java.awt.Window.dispatchEventImpl(Window.java:2746)
at java.awt.Component.dispatchEvent(Component.java:4711)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:90)
at java.awt.EventQueue$4.run(EventQueue.java:731)
at java.awt.EventQueue$4.run(EventQueue.java:729)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

那会是什么呢？你有什么建议来避免这个问题吗？非常感谢你提前

java
http
server
timeout
httpserver
EN

回答 1

Stack Overflow用户

发布于 2018-06-13 06:01:50

我不知道这个问题的原因。但是我决定使用Apache Java HTTP Client Library

下面是代码

代码语言：javascript
复制
public byte[] performRequest(HashMap<String, String> params, String host, int port, String handler, boolean isConnectionEncrypted) throws IOException, InterruptedException {
    URL url = composeUrl(params, host, port, handler, isConnectionEncrypted);

    HttpClient client = HttpClientBuilder.create().build();
    HttpGet request = new HttpGet(url.toString());

    // add request header
    HttpResponse response = client.execute(request);

    System.out.println("Response Code : " + response.getStatusLine().getStatusCode());

    BufferedReader rd = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));

    String t = "";
    String s = rd.readLine();
    while (s != null) {
        t = t + s;
        s = rd.readLine();
    }

    System.out.println("risposta letta:" + t);
    if (isConnectionEncrypted) {
        return cryptex.decrypt(t);
    } else {
        return t.getBytes();
    }
}
票数 0
EN
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：

https://stackoverflow.com/questions/50825845

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