深入理解Java Socket通信

package IO;

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

/**
 * Created by zhengbin06 on 2017/2/2.
 */
public class Client {
  public static void main(String[] args) {
    String msg = "Client Data";
    try {
      Socket socket = new Socket("127.0.0.1", 9090);

      // 先写、再读
      PrintWriter printWriter = new PrintWriter(socket.getOutputStream());
      // 发送数据
      printWriter.println(msg);
      printWriter.flush();
      // 获得服务端返回的数据
      BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
      String line = bufferedReader.readLine();
      System.out.println("received from server: " + line + "\ttime=" + new Date().getTime());
      // 关闭资源
      printWriter.close();
      bufferedReader.close();
      socket.close();
    } catch (IOException e) {
      e.printStackTrace();
    }
  }
}

package IO;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Date;

/**
 * Created by zhengbin06 on 2017/2/2.
 */
public class Server {
  private static Socket socket = null;
  private static ServerSocket serverSocket = null;
  public static void main(String[] args) throws IOException {
    BufferedReader bufferedReader = null;
    PrintWriter printWriter = null;
    try {
      // 创建一个ServerSocket监听9090端口
      serverSocket = new ServerSocket(9090);
      while (true) {
        System.out.println("开始等待请求。。。。");
        // 等待请求
        // 监听并接受到此套接字的连接。此方法在连接传入之前一直阻塞。
        socket = serverSocket.accept();
        System.out.println("接收到请求:" + socket.toString() + "\ttime=" + new Date().getTime());
        // 接收到请求后使用socket进行通信, 创建BufferedReader用于读取数据
        bufferedReader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
        String line = bufferedReader.readLine();
        System.out.println("received from client: " + line + "\ttime=" + new Date().getTime());
  
        // 创建PrintWriter, 用于发送数据
        printWriter = new PrintWriter(socket.getOutputStream());
        printWriter.println("received data: " + line + "\ttime=" + new Date().getTime());
        printWriter.flush();
      }
    } finally {
      // 关闭所有资源
      bufferedReader.close();
      printWriter.close();
      socket.close();
      serverSocket.close();
    }
  }
}