Java: 无法初始化 InetAddress

Question

出于某种原因，我似乎无法初始化 InetAddress 对象，我查看了文档，它与我的使用方式完全一样。

 InetAddress firstMachineAddress = InetAddress.getByName("129.26.70.95");
 InetAddress secondMachineAddress = InetAddress.getByName("129.26.70.108");

Eclipse 说：

Default constructor cannot handle exception type UnknownHostException thrown by implicit super constructor. Must define an explicit constructor

这到底是怎么回事？

Answer 1

您是否正在处理您调用的方法抛出的 UnknownHostException？

InetAddress firstMachineAddress;
try {
    firstMachineAddress = InetAddress.getByName("129.26.70.95");
} catch (UnknownHostException e) {
    // print exception, throw error,
    // try something else etc.
}

Answer 2

您的代码似乎在 class 的构造函数中，该构造函数由另一个 class 扩展，如下所示：

import java.net.*;

class SuperclassWithUnknownHostException {
    public SuperclassWithUnknownHostException() throws UnknownHostException {
        InetAddress firstMachineAddress = InetAddress.getByName("129.26.70.95");
        InetAddress secondMachineAddress = InetAddress.getByName("129.26.70.108");
    }
}

class SubclassCannotHandleException extends SuperclassWithUnknownHostException {

}

您需要将默认构造函数添加到引发异常的子class：

class SubclassCannotHandleException extends SuperclassWithUnknownHostException {
    public SubclassCannotHandleException() throws UnknownHostException {

    }
}

Answer 3

inetAddress 对象抛出一个异常，因此您需要围绕它包装一个 try-catch 或让您的方法也抛出异常。另外我相信你会收到错误，因为有一个你没有处理的异常返回。 getByName() 方法使用网址名称的字符串参数，例如 www.google.com 或 www.amazon.com 等等。

try{
        InetAddress Address = InetAddress.getByName("www.google.com"); 
        System.out.println(Address);
    }catch(UnknownHostException e){
        e.printStackTrace();
    }

这显示 www.google.com/64.233.177.147

Java: 无法初始化 InetAddress

Java: Cannot initialize InetAddress

java

inetaddress