java socket 编程入门

摘要: 在eclipse里实现一个server类和client类，它们在本机上进行通信。

Server类需要做的是：

1.用ServerSocket指定端口,不妨指定为8888，只要保证这个端口好在本机中未被占用即可，代码如下：

ServerSocket serverSocket = new ServerSocket(8888);

2.接受并监听发送请求的的客户端Socket,代码如下：

Socket socket = serverSocket.accept();

3.用输入流接受客户端的数据：

InputStream is = socket.getInputStream();

InputStreamReader isr = new InputStreamReader(is);

BufferedReader br = new BufferedReader(isr);

String clientSay = br.readLine();

System.out.println("Client Say:"+clientSay);

socket.shutdownInput();

4.处理完之后，用输出流给客户端的字母变为大写的在传回去：

OutputStream os = socket.getOutputStream();

PrintWriter pw = new PrintWriter(os);

pw.print(clientSay.toUpperCase());

pw.flush();

5.关闭资源：

pw.print(clientSay.toUpperCase());
pw.flush();
pw.close();
os.close();
br.close();
isr.close();
is.close();

完整程序如下：

package com.net;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;

public class Server {
public static void main(String[] args)
{
try {
ServerSocket serverSocket = new ServerSocket(8888);

Socket socket = serverSocket.accept();
//接受客户端的信息
InputStream is = socket.getInputStream();

InputStreamReader isr = new InputStreamReader(is);

BufferedReader br = new BufferedReader(isr);

String clientSay = br.readLine();
//	while(clientSay!=null)
//	{
System.out.println("Client Say:"+clientSay);
//clientSay= br.readLine();
//}
socket.shutdownInput();
//发送信息给客户端
OutputStream os = socket.getOutputStream();

PrintWriter pw = new PrintWriter(os);

pw.print(clientSay.toUpperCase());
pw.flush();
pw.close();
os.close();
br.close();
isr.close();
is.close();
socket.close();
serverSocket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}

Client类所做的事：

1.创建socket,指定主机地址，和端口号：

Socket socket = new Socket("127.0.0.1", 8888);

2.用输出流给指定的主机在控制台输入索要发送字母：

OutputStream os = socket.getOutputStream();

PrintWriter pw = new PrintWriter(os);

BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

String sendInfo = br.readLine();

pw.println(sendInfo);//注意换行，不然会出错，至于原因目前还不清楚，纠结。。。

pw.flush();

3.用输入流接受主机发过来的数据：

InputStream is = socket.getInputStream();

InputStreamReader isr = new InputStreamReader(is);

BufferedReader br1 = new BufferedReader(isr);

String serverSay = br1.readLine();

System.out.println("Server Say:"+serverSay);

4.关闭资源：

br.close();
pw.close();
os.close();
socket.close();

完整代码：

package com.net;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.Socket;
import java.net.UnknownHostException;

public class Client {
public static void main(String[] args)
{
try {
Socket socket = new Socket("127.0.0.1", 8888);

//给服务器发送消息
OutputStream os = socket.getOutputStream();

PrintWriter pw = new PrintWriter(os);
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
String sendInfo = br.readLine();
//while(sendInfo!=null)
//{
pw.println(sendInfo);
//}

pw.flush();
//接受服务端信息
InputStream is = socket.getInputStream();

InputStreamReader isr = new InputStreamReader(is);

BufferedReader br1 = new BufferedReader(isr);

String serverSay = br1.readLine();

System.out.println("Server Say:"+serverSay);
br.close();
pw.close();
os.close();
socket.close();

} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}

希望能给有需要的人到来帮助，有不当之处，还请大家多包涵，与指教。