Java 的ping 方法

 
import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.regex.Pattern;
public class Ping {
    // The default daytime port
    static int DAYTIME_PORT = 13;
    // The port we'll actually use
    static int port = DAYTIME_PORT;
    private String host;
    public String getHost() {
        return host;
    }
    public void setHost(String host) {
        this.host = host;
    }
   
    public void setPort(int port){
        this.port = port;
    }
    //    private String
    // Representation of a ping target
    //
    static class Target {
        InetSocketAddress address;
        SocketChannel channel;
        Exception failure;
        long connectStart;
        long connectFinish = 0;
        boolean shown = false;
        boolean pingResult = false;
        Target(String host) {
            try {
                address = new InetSocketAddress(InetAddress.getByName(host), port);
            } catch