java基础之socket

Socket应用中最常用的几个API:

 

Accept：

 

用于产生"阻塞"，直到接受到一个连接，并且返回一个客户端的Socket对象实例。"阻塞"是一个术语，它使程序运行暂时"停留"在这个地方，直到一个会话产生，然后程序继续；通常"阻塞"是由循环产生的。

 

getInputStream

 

获得网络连接输入，同时返回一个InputStream对象实例，。

 

getOutputStream

 

连接的另一端将得到输入，同时返回一个OutputStream对象实例。

 

开发一个最简单的client-server模型，少说废话，直接上实例：

 

服务器端：

 

 

import java.net.*; 
import java.io.*; 

public class Server 
{ 
private ServerSocket ss; 
private Socket socket; 
private BufferedReader in; 
private PrintWriter out; 

public Server() 
{ 
try 
{ 
ss = new ServerSocket(10000); 

while (true) 
{ 
socket = ss.accept(); //服务器端程序运行到这里会阻塞，直到指定端口上有连接申请，程序才会继续向下执行。
in = new BufferedReader(new InputStreamReader(socket.getInputStream())); 
out = new PrintWriter(socket.getOutputStream(),true); 

String line = in.readLine(); 
out.println("you input is :" + line); 
out.close(); 
in.close(); 
socket.close(); 
} 
ss.close(); 
} 
catch (IOException e) 
{} 
} 

public static void main(String[] args) 
{ 
new Server(); 
} 
} 

 

 

客户端：

 

 

import java.io.*; 
import java.net.*; 

public class Client 
{ 
Socket socket; 
BufferedReader in; 
PrintWriter out; 

public Client() 
{ 
try 
{ 
socket = new Socket("xxx.xxx.xxx.xxx", 10000); 
in = new BufferedReader(new InputStreamReader(socket.getInputStream())); 
out = new PrintWriter(socket.getOutputStream(),true); 
BufferedReader line = new BufferedReader(new InputStreamReader(System.in)); //将键盘中输入的内容包装成BufferedReader对象。

out.println(line.readLine()); //输出到服务器端。
line.close(); 
out.close(); 
in.close(); 
socket.close(); 
} 
catch (IOException e) 
{} 
} 

public static void main(String[] args) 
{ 
new Client(); 
} 
} 

 

 

如何完成多个客户端同时连接服务器端呢？看下面的实例：

 

 

import java.io.*; 
import java.net.*; 

public class Server extends ServerSocket 
{ 
private static final int SERVER_PORT = 10000; 

public Server() throws IOException 
{ 
super(SERVER_PORT); 

try 
{ 
while (true) 
{ 
Socket socket = accept(); 
new CreateServerThread(socket); //为每一个客户端创建一个线程来进行连接
} 
} 
catch (IOException e) 
{} 
finally 
{ 
close(); 
} 
} 
//--- CreateServerThread 
class CreateServerThread extends Thread 
{ 
private Socket client; 
private BufferedReader in; 
private PrintWriter out; 

public CreateServerThread(Socket s) throws IOException 
{ 
client = s; 

in = new BufferedReader(new InputStreamReader(client.getInputStream(), "GB2312")); 
out = new PrintWriter(client.getOutputStream(), true); 
out.println("--- Welcome ---"); 
start(); 
} 

public void run() 
{ 
try 
{ 
String line = in.readLine(); 

while (!line.equals("bye")) //如果客户端发送了"bye"字符串，则服务器端与该客户端的连接关闭。
{ 
String msg = createMessage(line); 
out.println(msg); 
line = in.readLine(); 
} 
out.println("--- See you, bye! ---"); 
client.close(); 
} 
catch (IOException e) 
{} 
} 

private String createMessage(String line) 
{ 
xxxxxxxxx; 
} 
} 

public static void main(String[] args) throws IOException 
{ 
new Server(); 
} 
} 

 

 

服务器端如何广播消息：

 

import java.io.*; 
import java.net.*; 
import java.util.*; 
import java.lang.*; 

public class Server extends ServerSocket 
{ 
private static ArrayList User_List = new ArrayList(); 
private static ArrayList Threader = new ArrayList(); 
private static LinkedList Message_Array = new LinkedList(); 
private static int Thread_Counter = 0; 
private static boolean isClear = true; 
protected static final int SERVER_PORT = 10000; 
protected FileOutputStream LOG_FILE = new FileOutputStream("d:/connect.log", true); 

public Server() throws FileNotFoundException, IOException 
{ 
super(SERVER_PORT); 
new Broadcast(); 

//append connection log 
Calendar now = Calendar.getInstance(); 
String str = "[" + now.getTime().toString() + "] Accepted a connection\015\012"; 
byte[] tmp = str.getBytes(); 
LOG_FILE.write(tmp); 

try 
{ 
while (true) 
{ 
Socket socket = accept(); 
new CreateServerThread(socket); 
} 
} 
finally 
{ 
close(); 
} 
} 

public static void main(String[] args) throws IOException 
{ 
new Server(); 
} 

//--- Broadcast 
class Broadcast extends Thread 
{ 
public Broadcast() 
{ 
start(); 
} 

public void run() 
{ 
while (true) 
{ 
if (!isClear) 
{ 
String tmp = (String)Message_Array.getFirst(); 

for (int i = 0; i < Threader.size(); i++) 
{ 
CreateServerThread client = (CreateServerThread)Threader.get(i); 
client.sendMessage(tmp); 
} 

Message_Array.removeFirst(); 
isClear = Message_Array.size() > 0 ? false : true; 
} 
} 
} 
} 

//--- CreateServerThread 
class CreateServerThread extends Thread 
{ 
private Socket client; 
private BufferedReader in; 
private PrintWriter out; 
private String Username; 

public CreateServerThread(Socket s) throws IOException 
{ 
client = s; 
in = new BufferedReader(new InputStreamReader(client.getInputStream())); 
out = new PrintWriter(client.getOutputStream(), true); 
out.println("--- Welcome to this chatroom ---"); 
out.println("Input your nickname:"); 
start(); 
} 

public void sendMessage(String msg) 
{ 
out.println(msg); 
} 

public void run() 
{ 
try 
{ 
int flag = 0; 
Thread_Counter++; 
String line = in.readLine(); 

while (!line.equals("bye")) 
{ 
if (line.equals("l")) 
{ 
out.println(listOnlineUsers()); 
line = in.readLine(); 
continue; 
} 

if (flag++ == 0) 
{ 
Username = line; 
User_List.add(Username); 
out.println(listOnlineUsers()); 
Threader.add(this); 
pushMessage("[< " + Username + " come on in >]"); 
} 
else 
{ 
pushMessage("<" + Username + ">" + line); 
} 

line = in.readLine(); 
} 

out.println("--- See you, bye! ---"); 
client.close(); 
} 
catch (IOException e) 
{} 
finally 
{ 
try 
{ 
client.close(); 
} 
catch (IOException e) 
{} 

Thread_Counter--; 
Threader.remove(this); 
User_List.remove(Username); 
pushMessage("[< " + Username + " left>]"); 
} 
} 


private String listOnlineUsers() 
{ 
String s ="-+- Online list -+-\015\012"; 

for (int i = 0; i < User_List.size(); i++) 
{ 
s += "[" + User_List.get(i) + "]\015\012"; 
} 

s += "-+---------------------+-"; 
return s; 
} 

private void pushMessage(String msg) 
{ 
Message_Array.addLast(msg); 
isClear = false; 
} 
} 
} 

 

 

 

评论

2 楼 liangsaifei 2013-01-06  

很不错，分享了。留着以后复习用！

1 楼 HelloOOOOO 2012-12-05  

   写的很不错后面有没有做去个可以用的程序来 ？[size=xx-large][/size]