Socket编程——客户端，服务器端的读写操作

URL网络编程，最大的特征就是一对一的响应！

1：客户端“写”，服务器端用于“读”

 package coreBookSocket2;

 import java.io.InputStreamReader;
 import java.io.Reader;
 import java.net.ServerSocket;
 import java.net.Socket;

 /*
  * 这边为服务器端的读取
  */

 /*
  * 1：首先建立一个ServerSocket监听在端口8888上面，服务器端只需要定义和客户端相同的端口号即可
  * 2：服务器端尝试接受来自客户端的请求
  * 3：和客户端连接好了之后，就可以读取来自客户端的输入信息
  * 4：定义一个StringBuilder对象用来保存来自客户端的信息
  * 5：关闭Reader，client,server等占用资源的对象
  */
 public class clientWtiteserverOpen {

     public static void main(String[] args) throws Exception{
         ServerSocket server=new ServerSocket(8888);
         Socket client =server.accept();
         Reader reader=new InputStreamReader(client.getInputStream());        //客户端获取自己的输入流
         char[] ch=new char[64];
         int len;
         StringBuilder sb=new StringBuilder();
         while( ( len=reader.read(ch) )!=-1)
         {
             sb.append(ch, 0, len);
         }
         System.out.println("From Client:"+sb);
         reader.close();
         client.close();
         server.close();
     }
 }

 package coreBookSocket2;

 import java.io.IOException;
 import java.io.OutputStreamWriter;
 import java.io.Writer;
 import java.net.Socket;
 import java.net.UnknownHostException;
 /*
  * 这边为客户端的写出
  */

 /*
  * 1：首先建立一个客户端的监听端口和IP地址，用相同的端口号与服务器端建立连接
  * 2：从客户端向服务器端写出数据
  */
 public class clientWriteserverOpen2 {
     public static void main(String[] args) throws UnknownHostException, IOException {

         Socket client=new Socket("127.0.0.1", 8888);
         Writer writer=new OutputStreamWriter(client.getOutputStream());
         writer.write("Hello server");
         writer.flush();
         writer.close();
         client.close();

     }

 }

2：客户端先写后读，服务器端先读后写

服务器端：

 package ClientAndServerWriteBoth;

 import java.io.IOException;
 import java.io.InputStreamReader;
 import java.io.OutputStreamWriter;
 import java.io.Reader;
 import java.io.Writer;
 import java.net.ServerSocket;
 import java.net.Socket;

 /*
  * 服务器端的编写
  *  服务器端是先读后写，那么客户端必定是先写后读
  */

 public class server {
     public static void main(String[] args) throws IOException {

         ServerSocket server=new ServerSocket(6666);
         Socket client=server.accept();

         Reader reader=new InputStreamReader(client.getInputStream());
         char[] ch=new char[20];
         int len;
         StringBuilder sb=new StringBuilder();
         String temp;
         int index;

         while(( len=reader.read(ch)) !=-1)
         {
             temp=new String(ch, 0, len);
             if( (index = temp.indexOf("eof")) != -1)//遇到eof时就结束接收,    这个地方没有怎么看明白？为什么到eof就结束？
             {
                 sb.append(temp.substring(0, index));
                 break;
             }
             sb.append(temp);
         }
         System.out.println("---From Client:  "+sb);

         Writer writer=new OutputStreamWriter(client.getOutputStream());
         writer.write("Hello Client I'm server! ");
         writer.flush();
         writer.close();
         reader.close();
         client.close();
         server.close();
     }
 }

客户端：

 package ClientAndServerWriteBoth;

 import java.io.IOException;
 import java.io.InputStreamReader;
 import java.io.OutputStreamWriter;
 import java.io.Reader;
 import java.io.Writer;
 import java.net.Socket;
 import java.net.UnknownHostException;

 /*
  * 客户端的编写，客户端先写后读
  * 1:客户端设定特定的端口号与服务器端连接
  */

 public class client {
     public static void main(String[] args) throws UnknownHostException, IOException {

         Socket client=new Socket("127.0.0.1", 6666);
         Writer writer=new OutputStreamWriter(client.getOutputStream());
         writer.write("Hello server， I'm your father,client!  哈哈哈哈哈");
         writer.flush();
         //写完了开始读

         Reader reader=new InputStreamReader(client.getInputStream());
         char[] ch=new char[20];
         int len;
         StringBuffer sb=new StringBuffer();
         String temp;
         int index;

         while( (len=reader.read(ch))!=-1)
         {
             temp=new String(ch, 0, len);
                     if(( index=temp.indexOf("eof"))!=-1)
                     {
                         sb.append(temp.substring(0, index));
                         break;
                     }
             sb.append(new String(ch, 0, len));
         }
         System.out.println("---From Server:  "+sb);
         writer.close();
         reader.close();
         client.close();
     }
 }

3：一个服务器端，对应多个客户端的连接

一个服务器端和多个客户端连接最好的方式就是用线程，因为服务器端接受客户端的连接的accept（）方法是阻塞式的。

服务器端：

 package oneServerForLotsClient;

 import java.io.IOException;
 import java.io.InputStreamReader;
 import java.io.OutputStreamWriter;
 import java.io.Reader;
 import java.io.Writer;
 import java.net.ServerSocket;
 import java.net.Socket;
 /*
  * 这边主要是服务器的demo的编写
  * 1：仍然是准备工作，让服务器端和客户端之间建立相同的端口号，实现连接。
  * 2:----因为客户端那边是多个对象连接服务器端，因此需要一个死循环让服务器一直接受连接客户端的连接请求！！！
  *                 建立一个新的线程去处理客户端的请求
  *3:服务器端首先是“读取” 客户端发送过来的信息
  */

 public class Server
 {
     public static void main(String[] args) throws IOException
     {

         ServerSocket server=new ServerSocket(6868);
         while(true)
             {
             Socket client=server.accept();
             new Thread(new Task(client) ).start();
             }
     }
 }

 package oneServerForLotsClient;

 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStreamReader;
 import java.io.OutputStreamWriter;
 import java.io.Writer;
 import java.net.Socket;
 /*
  * 这个类主要是用来处理新的线程，实现Runnable接口
  * 1：首先定一个构造方法，主要是为了初始化client对象
  * 2：同时重写run（）方法，这个方法主要开启新的方法用于 “ 读” 数据，和 “写” 数据的处理
  */

 public class Task implements Runnable {

     private  Socket client;

     public Task(Socket client)
     {
         this.client=client;
     }

     @Override
     public void run() {
         try {
             handlerSocket();
         } catch (IOException e) {
             e.printStackTrace();
         }
     }

     private void handlerSocket() throws IOException {
         BufferedReader br = new BufferedReader(new InputStreamReader(client.getInputStream()));
         StringBuilder sb = new StringBuilder();
         String temp;
         int index;
         while ((temp=br.readLine()) != null) {
            System.out.println(temp);
            if ((index = temp.indexOf("eof")) != -1) {//遇到eof时就结束接收
             sb.append(temp.substring(0, index));
                break;
            }
            sb.append(temp);
         }
         System.out.println("from client: " + sb);
         //读完后写一句
       Writer writer = new OutputStreamWriter(client.getOutputStream());
         writer.write("Hello Client.");
         writer.write("eof\n");
         writer.flush();
         writer.close();
         br.close();
         client.close();  

     }

 }

客户端

 package oneServerForLotsClient;

 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStreamReader;
 import java.io.OutputStreamWriter;
 import java.io.Writer;
 import java.net.Socket;
 import java.net.UnknownHostException;

 public class Client {
     public static void main(String[] args) throws UnknownHostException, IOException {

         Socket client=new Socket("127.0.0.1", 6868);

         Writer writer=new OutputStreamWriter(client.getOutputStream());
         writer.write("Hello,Server. My name is client! ");
         writer.write("eof\n");
         writer.flush();

         //写完了就开始读

         BufferedReader reader=new BufferedReader(new InputStreamReader(client.getInputStream()));
         StringBuffer buffer=new StringBuffer();
         String temp;
           int index;
           while ((temp=reader.readLine()) != null) {
              if ((index = temp.indexOf("eof")) != -1) {
                 buffer.append(temp.substring(0, index));
                 break;
              }
              buffer.append(temp);
           }
           System.out.println("from server: " + buffer);
           writer.close();
           reader.close();
           client.close(); 

     }

 }