英文:
Java InetAddress.getByName returns hostname/ip but it causes ping to fail
问题
我正在使用Corretto Java 11 JDK。
以下是我的方法：
public static boolean sendPingRequest(String host)
{
boolean value = false;
try
{
InetAddress myip = InetAddress.getByName(host);
System.out.println("发送Ping请求到：" + myip);
if (myip.isReachable(5000))
{
System.out.println("主机：" + host + " 可达");
value = true;
}
else
{
System.out.println("主机：" + host + " 不可达");
}
}
catch (UnknownHostException e)
{
System.out.println("无法访问此主机：" + e.getMessage());
e.printStackTrace();
}
catch (IOException e)
{
System.out.println("IO异常：" + e.getMessage());
}
return value;
}
当我在这里调用该方法时，它失败了：
String myHost = "www.google.com";
sendPingRequest(myHost);
发送Ping请求到www.google.com/108.177.111.106
主机：www.google.com 不可达
进程以退出代码0结束
从阅读文档中看来，InetAddress.getByName方法返回这个，但除非我能让它显示主机为IP 108.177.111.106，否则它每次都会失败。
英文:
I am using correto java 11 JDK
Here is my method:
public static boolean sendPingRequest(String host)
{
boolean value = false;
try
{
InetAddress myip = InetAddress.getByName(host);
System.out.println("Sending Ping Request to " + myip);
if (myip.isReachable(5000))
{
System.out.println("Host: " + host + " is reachable");
value = true;
}
else
{
System.out.println("Host: " + host + " is unreachable");
}
}
catch (UnknownHostException e)
{
System.out.println("I can't reach this host: " + e.getMessage());
e.printStackTrace();
}
catch (IOException e)
{
System.out.println("IO Exception" + e.getMessage());
}
return value;
}
When I can the method here it fails
String myHost = "www.google.com";
sendPingRequest(myHost);
Sending Ping Request to www.google.com/108.177.111.106
Host: www.google.com is unreachable
Process finished with exit code 0
From reading the documentation it looks like InetAddress.getByName method returns this but it will fail every time unless I can get it to show the host to be the IP 108.177.111.106.
答案1
得分: 1
我无法重现您的问题。这是我尝试过的：
public class Main {
public static void main(String[] args) {
System.out.println(sendPingRequest("www.google.com"));
System.out.println(sendPingRequest("74.125.195.106"));
System.out.println(sendPingRequest("108.177.111.106"));
}
public static boolean sendPingRequest(String host) {
boolean value = false;
try {
InetAddress myip = InetAddress.getByName(host);
System.out.println("正在发送 Ping 请求至 " + myip);
if (myip.isReachable(5000)) {
System.out.println("主机：" + host + " 是可达的");
value = true;
} else {
System.out.println("主机：" + host + " 是不可达的");
}
} catch (UnknownHostException e) {
System.out.println("我无法访问此主机：" + e.getMessage());
e.printStackTrace();
} catch (IOException e) {
System.out.println("IO 异常：" + e.getMessage());
}
return value;
}
}
输出为：
正在发送 Ping 请求至 www.google.com/74.125.195.105
主机：www.google.com 是可达的
true
正在发送 Ping 请求至 /74.125.195.106
主机：74.125.195.106 是可达的
true
正在发送 Ping 请求至 /108.177.111.106
主机：108.177.111.106 是可达的
true
也许您当时遇到了网络问题？
英文:
I can't reproduce your issue. Here's what I tried:
public class Main {
public static void main(String[] args) {
System.out.println(sendPingRequest("www.google.com"));
System.out.println(sendPingRequest("74.125.195.106"));
System.out.println(sendPingRequest("108.177.111.106"));
}
public static boolean sendPingRequest(String host) {
boolean value = false;
try {
InetAddress myip = InetAddress.getByName(host);
System.out.println("Sending Ping Request to " + myip);
if (myip.isReachable(5000)) {
System.out.println("Host: " + host + " is reachable");
value = true;
} else {
System.out.println("Host: " + host + " is unreachable");
}
} catch (UnknownHostException e) {
System.out.println("I can't reach this host: " + e.getMessage());
e.printStackTrace();
} catch (IOException e) {
System.out.println("IO Exception" + e.getMessage());
}
return value;
}
}
and the output is
Sending Ping Request to www.google.com/74.125.195.105
Host: www.google.com is reachable
true
Sending Ping Request to /74.125.195.106
Host: 74.125.195.106 is reachable
true
Sending Ping Request to /108.177.111.106
Host: 108.177.111.106 is reachable
true
Perhaps you were having network issues?
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