Socket通信

开篇

为什么要研究Socket？网络上的两个程序通过一个双向的通信连接实现数据的交换，这个连接的一端称为一个socket。socket本质是编程接口(API)，对TCP/IP的封装，TCP/IP也要提供可供程序员做网络开发所用的接口，这就是Socket编程接口；HTTP是轿车，提供了封装或者显示数据的具体形式；Socket是发动机，提供了网络通信的能力[百度百科]。

实现

服务端

package com.yzz.java.socket;

import java.io.*;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.UnknownHostException;

/**
 * Created by yzz on 2017/10/12.
 * mail:yzzstyle@163.com
 */

public class Server {
    private static Server server = new Server();
    private ServerSocket serverSocket;

    private Server(){
        try {
            InetAddress address = InetAddress.getByName("192.168.1.105");
            serverSocket = new ServerSocket(8087,1,address);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * 获取服务
     * @return
     */
    public static Server getServer(){
        return server;
    }

    public void readRequest(){
        try {
            Socket socket = serverSocket.accept();
            InputStream inputStream = socket.getInputStream();
            OutputStream outputStream = socket.getOutputStream();
            BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
            int i = 0;
            StringBuffer sb = new StringBuffer();
            //Thread.sleep(1000);
            if (reader.ready()) {
                while (i != -1) {
                    i = reader.read();
                    sb.append((char) i);
                }
            }
            System.out.println("收到客户端消息："+sb.toString());
            Thread.currentThread().sleep(500);
            sendResponse(outputStream);
            reader.close();
            socket.close();

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public void sendResponse(OutputStream outputStream){
        try {
            PrintWriter writer = new PrintWriter(outputStream,true);
            writer.write(System.currentTimeMillis()+"yzz");
            Thread.currentThread().sleep(500);
            writer.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

客户端

package com.yzz.java.socket;

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

/**
 * Created by yzz on 2017/10/12.
 * mail:yzzstyle@163.com
 */

public class Client {
    private int port;
    private String address;

    public Client(int port,String address) {
        this.port = port;
        this.address = address;
    }

    private Socket getConnection(){
        try {
            return new Socket(address,port);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

    public void sendRequest(){
        try {
            Socket socket = getConnection();
            OutputStream outputStream = socket.getOutputStream();
            InputStream inputStream = socket.getInputStream();
            PrintWriter writer = new PrintWriter(outputStream,true);
            writer.write(System.currentTimeMillis()+"yzz-client");
            Thread.currentThread().sleep(500);
            getResponse(inputStream);
            writer.close();
            socket.close();
            Thread.currentThread().sleep(500);

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public void getResponse(InputStream inputStream){
        try {
            boolean isOver = true;
            while (isOver) {
                BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
                Thread.sleep(1000);
                int i = 0;
                StringBuffer sb = new StringBuffer();
                if (reader.ready()) {
                    while (i != -1) {
                        i = reader.read();
                        sb.append((char) i);
                    }
                }

                System.out.println("收到服务端消息："+sb.toString());
                isOver = false;
                Thread.currentThread().sleep(1000);
            }
        }catch (Exception e){
            e.printStackTrace();
        }
    }
}

总结

这里的实现过于简单，很多问题没有考虑，当客户端连接服务器过多，就会出现java.net.ConnectException: Connection refused: connect的异常，所以我们要限制socket连接的个数。