Java网络编程 连接测试以及异常介绍

获取Socket的信息
getInetAddress():获得远程服务器的IP地址
getPort():获得远程服务器的端口
getLocalAddress():获得客户本地的IP地址
getLocalPort():获得客户本地的端口
getInputStream:获得输入流。如果Socket还没有连接，或者已经关闭，或者已经通过shutdownInout()方法关闭输入流，那么此方法会抛出IOException。
getOutputStream():获得输出流。如果Socket还没有连接，或者已经关闭，或者已经通过shutdownOutpit()方法关闭输出流，那么此方法会抛出IOException。

下面代码能够扫描主机从1到1024之间的端口。
PortScanner

import java.io.IOException;
import java.net.Socket;

public class PortScanner {
	
	public static void main(String args[]) {
		String host = "localhost";
		if (args.length > 0 ) {
			host = args[0];
		}
		new PortScanner().scan(host);
	}
	public void scan(String host) {
		Socket socket = null;
		for (int port = 0; port < 1024; port++) {
			try {
				socket = new Socket(host, port);
				System.out.println("There is a server on Port " + port);
				
			} catch (IOException e) {
				// TODO: handle exception
				System.out.println("Can't connect to port " + port);
				
			}finally
			{
				try {
					if (socket != null) {
						socket.close();
					}
				} catch (IOException e2) {
					// TODO: handle exception
					e2.printStackTrace();
				}
			}
		}
	}

}

下面代码主要介绍各种异常

ConnectTester

import java.io.IOException;
import java.net.BindException;
import java.net.ConnectException;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.SocketAddress;
import java.net.SocketTimeoutException;
import java.net.UnknownHostException;

public class ConnectTester {

	 public static void main(String args[]){
		    String host="www.baidu.com";
		    int port=80;
		    if(args.length>1){
		        host = "www.javathinker.org";
		        port= 80;
		    }
		    new ConnectTester().connect(host,port);
		  }
		  public void connect(String host,int port){
		    SocketAddress remoteAddr=new InetSocketAddress(host,port);
		    Socket socket=null;
		    String result="";
		    try {
		        long begin=System.currentTimeMillis();
		        socket = new Socket();
		        socket.connect(remoteAddr,1000); 
		        long end=System.currentTimeMillis();
		        result=(end-begin)+"ms";  
		    }catch (BindException e) {
		        result="Local address and port can't be binded";
		    }catch (UnknownHostException e) {
		        result="Unknown Host";
		    }catch (ConnectException e) {
		        result="Connection Refused";
		    }catch (SocketTimeoutException e) {
		        result="TimeOut";
		    }catch (IOException e) {
		        result="failure";
		    } finally {
		        try {
		            if(socket!=null)socket.close();
		        } catch (IOException e) {
		            e.printStackTrace();
		        }
		    }
		    System.out.println(remoteAddr+" : "+result);
		  }
}