server端

package socket.demo;

import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;


public class SocketServer {
    public static void main(String args[]){
        int port=5533;
        try {
            ServerSocket server=new ServerSocket(port);
            Socket socket=server.accept();
            System.out.println("server waiting");
            InputStream input=socket.getInputStream();
            byte[] bytes=new byte[1024];
            int length;
            StringBuilder sbBuilder=new StringBuilder();
            while((length=input.read(bytes))!=-1)   {
                sbBuilder.append(new String(bytes,0,length,"UTF-8"));
            }
            System.out.println("get msg from client"+sbBuilder);
            
            OutputStream out=socket.getOutputStream();
            out.write("i'm server,got your msg".getBytes());
            input.close();
            out.close();
            socket.close();
            server.close();
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        
    }

}

客户端:写完后，要立即关闭输出流（outputstream）

/**
* @author jy
*/
package socket.demo;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;
import java.net.UnknownHostException;


public class SocketClient {

   /**
    * @param args
    *<p>Description: </p>  
    */
   public static void main(String[] args) {

       int port=5533;
       String ip="127.0.0.1";
       try {
           Socket socket=new Socket(ip,port);
           String msg="hello";
           OutputStream out=socket.getOutputStream();
           out.write(msg.getBytes());
           socket.shutdownOutput();
           
           InputStream in=socket.getInputStream();
           byte[] bytes=new byte[1024];
           StringBuilder sbBuilder=new StringBuilder();
           int len;
           while((len=in.read(bytes))!=-1){
               sbBuilder.append(new String(bytes,0,len,"UTF-8"));
           }
           System.out.println("client got msg from server"+sbBuilder);
           //out.close();
           in.close();
           socket.close();
       } catch (UnknownHostException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (IOException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }
   }

}