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[英]difficulty in getting remote ip address from socket in java/android
[英]Getting ip address and putting it to socket -java
InetAddress ipAddr;
我要在這里做的是我需要獲取IP地址,然后將其放入套接字
public class L implements ActionListener{
public void actionPerformed(final ActionEvent e){
try {
s = new Socket(ipAddr.getHostAddress(), 6111);
DataOutputStream dout = new DataOutputStream(s.getOutputStream());
dout.writeUTF("L");
dout.writeUTF(" ");
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
我遇到此錯誤消息
線程“ AWT-EventQueue-0”中的異常java.lang.NullPointerException
之所以出現此錯誤,是因為您嘗試在null引用上調用method。 您需要先初始化ipAddr
然后才能使用它來調用此答案稍后介紹的方法。
s = new Socket(ipAddr.getHostAddress(), 6111); // your code doesn't initialise ipAddr.
當前,從您的問題尚不清楚您想要哪個IPAddress。 因此,我假設您正在尋找系統的回送地址(默認)。 有幾種初始化InetAddress的選項,如下所示:
String url = "localhost";
byte addr[] = {127, 0, 0, 1}; // loopback address
InetAddress ip1 = InetAddress.getByName(url);
InetAddress ip2 = InetAddress.getByAddress(addr);
InetAddress ip3 = InetAddress.getLocalHost();
// proceed with your sample code by using any of these InetAddress references
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