在扩展类上添加“抛出”？

Question

I'm making a simple application with the Socket API, but have run into a small issue that I haven't found the answer for.

The application is supposed to be multi-threaded, so that the main method starts both the server and client threads.

public class UDPClientServer1 extends Thread

However, since the the Socket classes need to throw some specific exceptions, I must also do this:

public void runClient() throws SocketException, UnknownHostException, IOException

and similarly for the runServer() method.

Not that there's anything wrong with that, but is there a more elegant solution? Something along the lines of :

public class UDPClientServer1 extends Thread, throws Exception

Answer 1

Ideally you may want to wrap the exception that your throw, either converting it to a RuntimeException if the error is unrecoverable, or at least a more appropriate / encapsulated exception.

Eg

public void runClient throws ClientException
{
    try
    {
        // do something
    } catch (Exception e)
    {
        log.error("Exception encountered in client",e);
        throw new ClientException("Unrecoverable client exception encountered",e);
        // or: throw new RuntimeException("Unrecoverable client exception",e);
    }
}

ClientException in the above is your own exception that you would need to create. Its purpose is to encapsulate the implementation details of corresponding exceptions from any calling code.

Using a RuntimeException , however, may be more appropriate if there is no reasonable way for the calling code to respond to the exception. When throwing a RuntimeException you do not have to declare it in the method signature and calling code does not need to explicitly handle it (although it should be handled at some point).