How to use URLConnection Timeout

问题:

I am trying to sort through a list of SOCKS proxies, and figure out which ones have a connect and read time of less than 1000ms, here is my code

for(Proxy p : proxies) {
            try {
            URLConnection testConnection = testUrl.openConnection(p);
            testConnection.setConnectTimeout(TIMEOUT_VALUE);
            testConnection.setReadTimeout(TIMEOUT_VALUE);
            success.add(p);
            } catch(SocketTimeoutException ste) {
                System.out.println("Proxy " + p.address().toString() + " timed out.");
            }
        }

But every single one of them passes the test, even when I do TIMEOUT_VALUE = 1; What am I doing wrong? Thanks for any help.

回答1:

I assume your problem is you don't read anything from connection. If I set TIMEOUT_VALUE too low, I get an exception. Whether I read all response or only one line did not affect the resulting time, I guess it is because I got whole answer in one packet.

Here is the measurement I used (without proxies):

    int TIMEOUT_VALUE = 1000;
    try {
        URL testUrl = new URL("http://google.com");
        StringBuilder answer = new StringBuilder(100000);

        long start = System.nanoTime();

        URLConnection testConnection = testUrl.openConnection();
        testConnection.setConnectTimeout(TIMEOUT_VALUE);
        testConnection.setReadTimeout(TIMEOUT_VALUE);
        BufferedReader in = new BufferedReader(new InputStreamReader(testConnection.getInputStream()));
        String inputLine;

        while ((inputLine = in.readLine()) != null) {
            answer.append(inputLine);
            answer.append("\n");
        }
        in.close();

        long elapsed = System.nanoTime() - start;
        System.out.println("Elapsed (ms): " + elapsed / 1000000);
        System.out.println("Answer:");
        System.out.println(answer);
    } catch (SocketTimeoutException e) {
        System.out.println("More than " + TIMEOUT_VALUE + " elapsed.");
    }

回答2:

I use

    System.getProperties().put("proxySet", "true");
    System.getProperties().put("http.proxyHost", "192.168.10.121");
    System.getProperties().put("http.proxyPort", "8080");
    //System.getProperties().put("http.nonProxyHosts", "8080");