第二章 Socket用法详解

 1 Socket() 
 2 //Creates an unconnected socket, with the system-default type of SocketImpl.
 3  
 4 Socket(InetAddress address, int port) 
 5 //Creates a stream socket and connects it to the specified port number at the  
 6 //specified IP address.
 7  
 8 Socket(InetAddress host, int port, boolean stream) 
 9 //Deprecated.  
10 //Use DatagramSocket instead for UDP transport.
11  
12 Socket(InetAddress address, int port, InetAddress localAddr, int localPort) 
13 //Creates a socket and connects it to the specified remote address on the 
14 //specified remote port.
15  
16 Socket(Proxy proxy) 
17 //Creates an unconnected socket, specifying the type of proxy, if any, that 
18 //should be used regardless of any other settings.
19  
20 Socket(SocketImpl impl) 
21 //Creates an unconnected Socket with a user-specified SocketImpl.
22  
23 Socket(String host, int port) 
24 //Creates a stream socket and connects it to the specified port number on the  
25 named host.
26  
27 Socket(String host, int port, boolean stream) 
28 //Deprecated.  
29 //Use DatagramSocket instead for UDP transport.
30  
31 Socket(String host, int port, InetAddress localAddr, int localPort) 
32 //Creates a socket and connects it to the specified remote host on the specified 
33 //remote port. 

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

public class PortScanner {

    public static void main(String[] args) {
        String host="localhost";
        new PortScanner().scan(host);

    }
    public void scan(String host){
        Socket socket=null;
        for(int port=1;port<=1024;port++){
            try{
                socket=new Socket(host,port);
                System.out.println("There is a server on port "+port);
            }catch(IOException e){
                System.out.println("Can‘t connect to port "+port);
            }finally{
                if(socket!=null){
                    try {
                        socket.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }
        }
    }

}

Socket socket = new Socket();
//SocketAddress 提供不可变对象，供套接字用于绑定、连接或用作返回值。
SocketAddress remoteAddr = new InetSocketAddress("localhost",8000);
//超时未连接时，会抛出超时异常。
socket.connect(remoteAddr,60000);//毫秒为单位，0表示用于不超时

 Socket(InetAddress address,int port,InetAddress localAddress,int localPort)
 Socket(String host,int port,int port,InetAddress localAddress,int localPort)

 1 InetAddress getInetAddress() 
 2 //Returns the address to which the socket is connected.
 3  
 4 InputStream getInputStream() 
 5 //Returns an input stream for this socket.
 6 
 7 OutputStream getOutputStream() 
 8 //Returns an output stream for this socket. 
 9  
10 int getPort() 
11 //Returns the remote port number to which this socket is connected. 
12  
13 InetAddress getLocalAddress() 
14 //Gets the local address to which the socket is bound.
15  
16 int getLocalPort() 
17 //Returns the local port number to which this socket is bound. 

if(socket!=null){
    try {
        socket.close();
    } catch (IOException e) {
        e.printStackTrace();
        }
    }
}

boolean isBound() 
//Returns the binding state of the socket.
 
boolean isClosed() 
//Returns the closed state of the socket.
 
boolean isConnected()  
//Returns the connection state of the socket.