http://stackoverflow.com/questions/9922543/why-does-inetaddress-isreachable-return-false-when-i-can-ping-the-ip-address
仕方がないのでpingをコマンドライン経由で打つ羽目に．かなりいい加減な実装だがまあ最初のイテレーション(だけ)ではよいとする．
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
/**
* Created by neko32 on 2016/09/11.
*/
public class Ping {
private String resultCache = null;
private static final Logger LOG = LoggerFactory.getLogger(Ping.class);
public boolean isReachable() {
if(resultCache == null)
throw new IllegalStateException("run start() first");
LOG.debug(resultCache);
boolean decision = false;
decision = resultCache.contains("(0%");
if(resultCache.contains("unreachable") ||
resultCache.contains("到達できません") ||
resultCache.contains("timeout") ||
resultCache.contains("タイムアウト")) {
decision = false;
}
return decision;
}
public void start(final String destIP) throws IOException {
final String cmd = String.format("ping %s", destIP);
Process p = Runtime.getRuntime().exec(cmd);
StringBuilder sb = new StringBuilder();
try(InputStreamReader is = new InputStreamReader(p.getInputStream(), "MS932");
BufferedReader br = new BufferedReader(is)) {
String line = null;
while((line = br.readLine()) != null) {
sb.append(line);
}
}
resultCache = sb.toString();
}
}
こちらはそのユニットテスト．
mport org.scalatest.{GivenWhenThen, FeatureSpec}
import org.tanuneko.im.net.util.Ping
/**
* Created by neko32 on 2016/09/11.
*/
class PingSpec extends FeatureSpec with GivenWhenThen {
info("Ping is a small utility to run ping through command line.")
info("Because InetAddress.isReachable() doesn't rely on actual ping but ECHO(TCP 7), not reliable")
feature("Ping") {
scenario("Ping succeeds against known ip address(local loopback)") {
When("Ping is executed")
val ping = new Ping
ping.start("127.0.0.1")
Then("Ping should succeed")
assert(ping.isReachable)
}
}
feature("Ping") {
scenario("Ping fails against unknown ip address") {
When("Ping is executed")
val ping = new Ping
ping.start("3.99.156.254")
Then("Ping should fail")
assert(!ping.isReachable)
}
}
}
