ServerSocket serverSocket=new ServerSocket(8888);

  BufferReader reader = new BufferedReader(
                  new InputStreamReader(socket.getInputStream()));
  PrintWriter writer = new PrintWriter(
                  new OutputStreamWriter(socket.getOutputStream()));

import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Scanner;
/**
* Created by Mezereon on 2017/3/1.
*/
public class TCPServer {
 private Socket socket;
 private ServerSocket serverSocket;
 private BufferedReader reader;
 private PrintWriter writer;
 private Scanner scanner = new Scanner(System.in);
 //開啟服務(wù)
 public void run() throws IOException {
     startTheSocket();
 }
 public void startTheSocket() throws IOException {
   serverSocket=new ServerSocket(18080); //打開18080端口等待連接
   acceptTheSocket();//接受連接并且初始化Socket，reader，writer
   openTheNewThreadToGetMessageFromClient();
   while(true) {   
      getYourMessage();//獲取鍵盤數(shù)據(jù)并作為輸入
   }
 }
 //接受連接并且初始化Socket，reader，writer
 private void acceptTheSocket() throws IOException {
   socket=serverSocket.accept();//阻塞方法，用于接受Socket連接
   System.out.println("Some one connect me ，it is "+socket.getLocalSocketAddress());//打印地址
   System.out.println("It's port is "+socket.getPort());//打印端口號(hào)
   reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));//獲得輸入流
   writer = new PrintWriter(new OutputStreamWriter(socket.getOutputStream()));//獲得輸出流
 }
 //掃描鍵盤并輸入數(shù)據(jù)
 private void getYourMessage() throws IOException {
   String yourMessage = scanner.nextLine();
   checkYourMessage(yourMessage);//檢查發(fā)送給客戶端的信息
   writer.println(yourMessage);//發(fā)送信息
   writer.flush();//flush方法用于清空緩沖區(qū)，注意的是如果不flush你的信息可能發(fā)不出去一直存留在緩沖區(qū)
 }
 //用于檢查是否退出
 private void checkYourMessage(String yourMessage) throws IOException {
   //關(guān)閉各種
   if (yourMessage.equals("exit")) {
     socket.close();
     writer.close();
     reader.close();
     System.exit(0);
   }
 }
 //開啟一個(gè)新的線程來監(jiān)聽客戶端發(fā)來的信息
 private void openTheNewThreadToGetMessageFromClient() throws IOException {
   //開啟一個(gè)新的線程
   new Thread(new Runnable() {
     @Override
     public void run() {
       getTheMessageFromClient();
     }
   }).start();

 }
 //不斷循環(huán)來獲取客戶端發(fā)來的信息
 private void getTheMessageFromClient() {
   while(true) {
     String messageFromClient = null;
     try {
       messageFromClient = reader.readLine();
     } catch (IOException e) {
       e.printStackTrace();
     }
     printTheMessage(messageFromClient);//打印客戶端發(fā)來的信息
   }
 }
 //打印客戶端發(fā)來的信息
 private void printTheMessage(String messageFromClient) {
   if(messageFromClient!=null)
     System.out.println("He say:"+messageFromClient);
 }    
}

import java.io.*;
import java.net.Socket;
import java.util.Scanner;

/**
 * Created by Mezereon on 2017/2/27.
 */
public class TCPClient {

  private Socket socket;
  private BufferedReader reader ;
  private PrintWriter writer;
  private Scanner scanner = new Scanner(System.in);

  //開啟Socket來連接
  public void run() throws IOException{
      startTheSocket();
  }

  //開始連接服務(wù)端
  private void startTheSocket() throws IOException{
      toConnectTheServer();//創(chuàng)建Socket并初始化
      openTheThreadToReceiveInfoFromServer();//開啟一個(gè)新的線程來接受服務(wù)端發(fā)來的信息

      //一個(gè)循環(huán)，用于讀取鍵盤的輸入
      while(true) {
        String yourMessage = scanner.nextLine();
        //不為空則發(fā)送信息
        if(yourMessage!=null) {
          writer.println(yourMessage);
          writer.flush();//記得flush清空緩沖區(qū)
        }
        //判斷是否退出
        if (yourMessage.equals("exit")) {
          disConnect();
          System.exit(0);
        }
      }
  }

  //創(chuàng)建一個(gè)Socket來連接本機(jī)的18080端口的服務(wù)端并初始化reader和writer
  private void toConnectTheServer() throws IOException {
    socket=new Socket("127.0.0.1",18080);
    reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
    writer = new PrintWriter(new OutputStreamWriter(socket.getOutputStream()),true);
  }

  private void openTheThreadToReceiveInfoFromServer() throws IOException {
    new Thread(new Runnable() {
      @Override
      public void run() {
        try {
          printMessage();//打印從服務(wù)端收到的信息
        } catch (IOException e) {
          e.printStackTrace();
        }
      }
    }).start();
  }

  //循環(huán)不斷讀取服務(wù)端的信息
  private void printMessage() throws IOException {
    while (true) {
      String messageFromServer = null;
      try {
        messageFromServer = reader.readLine();//讀取信息
        System.out.println("He say:" + messageFromServer);//打印信息
      } catch (IOException e) {
        e.printStackTrace();
      } catch (NullPointerException e) {

      }
      if(messageFromServer.equals("exit")){
        disConnect();//關(guān)閉連接
        System.exit(0);
      }
    }
  }

  //關(guān)閉各種
  private void disConnect() throws IOException {
    socket.close();
    reader.close();
    writer.close();
  }

}