Socket通常也称做”套接字“，用于描述IP地址和端口，废话不多说，它就是网络通信过程中端点的抽象表示。值得一提的是，Java在包java.net中提供了两个类Socket和ServerSocket，分别用来表示双向连接的客户端和服务端。这是两个封装得非常好的类，使用起来很方便！
下面将首先创建一个SocketServer的类作为服务端如下，该服务端实现了多线程机制，可以在特定端口处监听多个客户请求，一旦有客户请求，Server总是会创建一个服务纯种来服务新来的客户，而自己继续监听。程序中accept()是一个阻塞函数，所谓阻塞性方法就是说该方法被调用后将等待客户的请求，直到有一个客户启动并请求连接到相同的端口，然后accept()返回一个对应于客户的Socket。这时，客户方和服务方都建立了用于通信的Socket，接下来就是由各个Socket分别打开各自的输入、输出流。
package HA.Socket;
import java.io.*;
import java.net.*;
public class SocketServer {
ServerSocket sever;
public SocketServer(int port){
try{
sever = new ServerSocket(port);
}catch(IOException e){
e.printStackTrace();
}
}
public void beginListen(){
while(true){
try{
final Socket socket = sever.accept();
new Thread(new Runnable(){
public void run(){
BufferedReader in;
try{
in = new BufferedReader(new InputStreamReader(socket.getInputStream(),"UTF-8"));
PrintWriter out = new PrintWriter(socket.getOutputStream());
while (!socket.isClosed()){
String str;
str = in.readLine();
out.println("Hello!world!! " + str);
out.flush();
if (str == null || str.equals("end"))
break;
System.out.println(str);
}
socket.close();
}catch(IOException e){
e.printStackTrace();
}
}
}).start();
}catch(IOException e){
e.printStackTrace();
}
}
}
}
import java.io.*;
import java.net.*;
public class SocketClient {
static Socket client;
public SocketClient(String site, int port){
try{
client = new Socket(site,port);
System.out.println("Client is created! site:"+site+" port:"+port);
}catch (UnknownHostException e){
e.printStackTrace();
}catch (IOException e){
e.printStackTrace();
}
}
public String sendMsg(String msg){
try{
BufferedReader in = new BufferedReader(new InputStreamReader(client.getInputStream()));
PrintWriter out = new PrintWriter(client.getOutputStream());
out.println(msg);
out.flush();
return in.readLine();
}catch(IOException e){
e.printStackTrace();
}
return "";
}
public void closeSocket(){
try{
client.close();
}catch(IOException e){
e.printStackTrace();
}
}
public static void main(String[] args) throws Exception{
}
}
接下来就是来测试Socket通信了！package HA.Socket;
先运行TestSocketServer类，打开服务端，在12345端口处监听！
package HA.Socket;
public class TestSocketServer {
public static void main(String[] argvs){
SocketServer server = new SocketServer(12345);
server.beginListen();
}
}
再运行TestSocketClient类：
package HA.Socket;
public class TestSocketClient {
public static void main(String[] args){
SocketClient client = new SocketClient("127.0.0.1",12345);
System.out.println(client.sendMsg("nimei1"));
client.closeSocket();
SocketClient client1 = new SocketClient("127.0.0.1",12345);
System.out.println(client1.sendMsg("nimei1111"));
client1.closeSocket();
SocketClient client11 = new SocketClient("127.0.0.1",12345);
System.out.println(client11.sendMsg("nimei11111111"));
client11.closeSocket();
SocketClient client111 = new SocketClient("127.0.0.1",12345);
System.out.println(client111.sendMsg("nimei11111111111111111"));
client111.closeSocket();
}
}
输出结果如下：
服务端：
Client is created! site:127.0.0.1 port:12345
Hello!world!! nimei1
Client is created! site:127.0.0.1 port:12345
Hello!world!! nimei1111
Client is created! site:127.0.0.1 port:12345
Hello!world!! nimei11111111
Client is created! site:127.0.0.1 port:12345
Hello!world!! nimei11111111111111111
客户端：
nimei1
nimei1111
nimei11111111
nimei11111111111111111
